ALKALI-SILICAREACTION INPORTLAND CEMENTCONCRETE:TESTING METHODSANDMITIGATIONALTERNATIVES

RESEARCH REPORT ICAR - 301-1f

Sponsored by the Aggregates Foundation

for Technology, Research and Education

Copyright

by

Wissam Elias Touma

2000

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ALKALI-SILICA REACTION IN PORTLAND CEMENT CONCRETE:

TESTING METHODS AND MITIGATION ALTERNATIVES

by

Wissam Elias Touma, B.S., M.S.

Dissertation

Presented to the Faculty of the Graduate School of The University of Texas at Austin

in Partial Fulfillment of the Requirements

for the Degree of

DOCTOR OF PHILOSOPHY

The University of Texas At Austin

August 2000

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ALKALI-SILICA REACTION IN PORTLAND

CEMENT CONCRETE: TESTING METHODS AND MITIGATION

ALTERNATIVES

Approved by Dissertation Committee:

_________________________ Ramon L. Carrasquillo, Co-Supervisor _________________________ David W. Fowler, Co-Supervisor

_________________________ John E. Breen

_________________________ Michael E. Kreger

_________________________ Harovel G. Wheat

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This dissertation is dedicated to my lovely wife Joanna with love and admiration and to my Family with thanks and appreciation.

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ACKNOWLEDGMENTS

First, I would like to thank God for his blessings, protection, and love.

I would also like to express my gratitude to my supervisors, Dr. Ramon

Carrasquillo and Dr. David Fowler for their assistance throughout this research

project. Great thanks also to all the professors that served as members on my

committee.

My greatest thanks and love to my parents Elias and Rose Touma. Thank you for

the financial and spiritual support. I could not have reached this far without you. I am

forever grateful and indebted for your kindness and generosity. Also great thanks for

all my brothers and sisters and their families.

Last but not least, I would like to acknowledge my lovely wife, Joanna, to whom I

owe my life, my love, and my soul. This dissertation is dedicated to my wife who has

always been supportive and loving. I love you with all my heart and hope that our

life together will be filled with love and success.

Wissam E. Touma August 2000

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ALKALI-SILICA REACTION IN PORTLAND CEMENT CONCRETE:

TESTING METHODS AND MITIGATION ALTERNATIVES

Publication No.

Wissam Elias Touma, Ph.D. The University of Texas at Austin, 2000

Supervisors: David W. Fowler Ramon L. Carrasquillo

Identifying the susceptibility of an aggregate to the alkali-silica reaction (ASR)

before using it in concrete is one of the most efficient practices for preventing

damage and failure. Several tests have been developed for identifying aggregates

subject to ASR, but each has its limitations. A three-year research study was initiated

on January 1, 1998 at the University of Texas at Austin for investigating ASR in

portland cement concrete. The scope of the study was essentially three fold: (1)

investigate the predictive ability of ASTM C 1260 and C 1293, (2) develop more

accurate and more efficient modifications of these procedures, and (3) investigate

ASR mitigation alternatives.

Aggregate samples from 14 sources from around the United States were acquired

for the investigation. Aggregates were used in an extensive testing program, during

which guidelines for predicting the potential alkali-silica reactivity of aggregates

were developed and recommendations for minimizing concrete damage due to ASR

were formulated. This dissertation includes an extensive review of the state-of-the-

art of ASR, an illustration of the results generated, and a discussion of the

conclusions obtained throughout this study.

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TABLE OF CONTENTS

Chapter Page

CHAPTER ONE - INTRODUCTION 1.1 GENERAL ............................................................................................. 1 1.2 BACKGROUND AND PROJECT JUSTIFICATION ............................................ 1 1.2.1 ASR Survey ..................................................................................................... 1 1.2.2 Testing Procedures ......................................................................................... 3 1.2.3 Mitigation Alternatives ................................................................................... 5 1.3 PROJECT OBJECTIVE .......................................................................................... 6 1.4 WORK PLAN .......................................................................................................... 7 1.5 BENEFITS .............................................................................................................. 9 CHAPTER TWO – ALKALI-SILICA REACTION MECHANISMS 2.1 GENERAL DEFINITION ..................................................................................... 11 2.2 CONTRIBUTION OF THE SILICA TO THE REACTION ................................. 12 2.3 ALKALI CONTRIBUTION TO THE REACTION …….……………………...14 CHAPTER THREE – REVIEW OF SELECTIVE RESEARCH 3.1 INTRODUCTION ............................................................................................... 16 3.2 TESTING FOR POTENTIAL REACTIVITY OF AGGREGATES ................... 16 3.2.1 Petrographic Examination: ASTM C 295 .................................................. 17 3.2.2 Chemical Method: ASTM C 289 .............................................................. 18 3.2.3 Mortar Bar Method: ASTM C 227 ............................................................. 18 3.2.4 Accelerated Mortar Bar Method: ASTM C 1260 ....................................... 21 3.2.5 Autoclave Mortar Bar Methods .................................................................. 22 3.2.6 Concrete Prism Method: CAN/CSA-A23.2-14A (ASTM C 1293) ............ 23 3.2.7 Accelerated Concrete Prism Method (Used in Quebec) ............................. 24 3.2.8 The Duggan Test ....................................................................................... 24 3.2.9 Conclusions of the Survey by Fournier and Bérubé ................................... 24 3.3 ASR MITIGATION MEASURES ...................................................................... 27 3.3.1 Minimizing Alkalis ..................................................................................... 29 3.3.2 Effectiveness of Supplementary Cementing Materials ............................. 30 3.3.3 Control Mechanisms of Supplementary Cementitious Materials ............... 57 3.4 FINAL REMARKS ............................................................................................. 59 CHAPTER FOUR – REVIEW OF INTERNATIONAL EXPERIENCE WITH ASR 4.1 INTRODUCTION ................................................................................................ 60 4.2 RILEM SURVEY ................................................................................................. 60 4.2.1 Specific RILEM Survey Conclusions Related to Testing ........................... 62 4.3 ASR IN AUSTRALIA .......................................................................................... 73 4.3.1 Evaluating the Reactivity of Aggregates ..................................................... 63 4.3.2 ASR Preventive Measures ........................................................................... 68 4.4 ASR IN BEIJING ................................................................................................. 69 4.5 ASR IN CANADA ............................................................................................... 70

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4.5.1 Evaluating the Reactivity of Aggregates ..................................................... 70 4.5.1.1 “Testing Concrete for AAR in NaOH and NaCl Solutions at 380C and 800C” ............................................................................ 71 4.5.1.2 “Effectiveness of High-Volume Fly Ash Concrete in Controlling Expansion Due to Alkali-Silica Reaction” ..................................... 73 4.5.1.3 Inter-Laboratory Test Evaluation ....................................................... 76 4.5.2 ASR Preventive Measures ........................................................................... 77 4.5.2.1 Field Performance .............................................................................. 78 4.5.2.2 Laboratory Studies ............................................................................. 78 4.5.2.3 Preventive Measures .......................................................................... 80 4.6 ASR IN CHINA ............................................................................................. 81 4.6.1 Evaluating the Reactivity of Aggregates ..................................................... 81 4.6.2 ASR Preventive Measures ........................................................................... 82 4.7 ASR IN FRANCE ................................................................................................. 82 4.7.1 Evaluating the Reactivity of Aggregates ..................................................... 82 4.7.2 ASR Preventive Measures ........................................................................... 84 4.7.2.1 Alkali Content of the Concrete .......................................................... 86 4.7.2.2 Acceptable Level of Risk and Environmental Conditions ................. 86 4.8 ASR IN THE NETHERLANDS ........................................................................... 91 4.8.1 Evaluating the Reactivity of Aggregates ..................................................... 92 4.8.2 ASR Preventive Measures ........................................................................... 92 4.9 ASR IN KOREA ................................................................................................... 93 4.10 ASR IN NORWAY ............................................................................................. 93 4.10.1 Evaluating the Reactivity of Aggregates ................................................... 93 4.10.1.1 Petrographic Analysis ...................................................................... 94 4.10.1.2 NBRI Accelerated Mortar Bar Test (C 1260) .................................. 94 4.10.1.3 The Concrete Prism Test .................................................................. 95 4.10.1.4 Testing Protocol ............................................................................... 95 4.10.2 ASR Preventive Measures ......................................................................... 95 4.11 ASR IN PORTUGAL ......................................................................................... 95 4.12 ASR IN NEW ZEALAND .................................................................................. 96 4.13 ASR IN HONG KONG ...................................................................................... 97 4.14 ASR IN TAIWAN .............................................................................................. 97 4.15 ASR IN ITALY .................................................................................................. 98 4.16 ASR IN ICELAND ............................................................................................. 99 4.17 ASR IN THE UNITED KINGDOM OF BRITAN ............................................. 99 4.18 ASR IN THE UNITED STATES OF AMERICA ............................................ 102

4.18.1 DOT Survey ............................................................................................ 103 4.18.2 Strategic Highway Research Program (SHRP) ....................................... 103 4.18.3 ASR in North Carolina ............................................................................. 109 4.18.4 ASR in Virginia ........................................................................................ 109 4.18.5 ASR in South Dakota (Polynomial and Avrami) .................................... 111 4.18.6 Mid-Atlantic Regional Technical Committee .......................................... 112 4.18.7 AASHTO ASR Lead State Team ............................................................. 114 4.18.8 Portland Cement Association ................................................................... 115

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4.18.9 The National Aggregate Association ....................................................... 115 4.18.10 Lithium as A Preventive Measure .......................................................... 117

4.19 ASR IN DENMARK ........................................................................................ 119 4.19.1 Alkali Content of the Concrete ................................................................ 119 4.19.2 Environmental Classification .................................................................. 120 4.19.3 Aggregate Specification .......................................................................... 120 4.19.4 Concrete Specification ............................................................................ 121 4.20 FINAL REMARKS ........................................................................................... 122 CHAPTER FIVE – TESTING MATERIALS 5.1 AGGREGATE SELECTION ............................................................................. 123 5.2 OTHER TESTING MATERIALS ...................................................................... 126 CHAPTER SIX – LABORATORY TESTING PROCEDURES 6.1 INTRODUCTION .............................................................................................. 132 6.2 STAGE 1: AGGREGATE TESTING AND PREPARATION .......................... 132 6.3 STAGE 2: TESTING FOR THE POTENTIAL ALKALI-SILICA REACTIVITY OF AGGREGATES ............................................... 135 6.3.1 Aggregate Testing Using ASTM C 227 .................................................... 135 6.3.2 Aggregate Testing Using ASTM C 1260 .................................................. 135 6.3.3 Aggregate Testing Using ASTM C 1293 .................................................. 142 6.4 STAGE 3: ASR MITIGATION ALTERNATIVES ........................................... 147 6.5 SUMMARY OF THE TESTING PROGRAM ................................................... 149 CHAPTER SEVEN – MIXTURE PROPORTIONS 7.1 ASTM C 227 MIXTURE PROPORTIONS ....................................................... 150 7.2 ASTM C 1260 MIXTURE PROPORTIONS ................................................... 151 7.3 ASTM C 1293 MIXTURE PROPORTIONS ................................................... 160 CHAPTER EIGHT – MISCELLANEOUS TESTING RESULTS 8.1 INTRODUCTION .............................................................................................. 169 8.2 PHYSICAL PROPERTY TESTS RESULTS ................................................... 169 8.3 PETROGRAPHIC EXAMINATION, CHEMICAL ANALYSIS AND FIELD PERFORMANCE DOCUMENTATION ............................................ 169 8.4 ASTM C 227 RESULTS OF TESTING .......................................................... 173 CHAPTER NINE – ASTM C 1260 RESULTS AND DISCUSSION 9.1 ASTM C 1260 ..................................................................................................... 178 9.2 ASTM C 1260 PERFORMED NY THE NAA ................................................... 183 9.3 MODIFIED C 1260: EXPANSION UP TO 56 DAYS ...................................... 185 9.4 MODIFIED C 1260: ADJUSTING WATER CONTENT TO ACCOUNT FOR AGGREGATES ABSORPTION ............................................................... 189 9.5 MODIFIED C 1260: USING A POLYNOMIAL FITTING PROCEDURE FOR INTERPRETATION OF RESULTS ......................................................... 193 9.6 MODIFIED C 1260: USING KOLMOGOROV-AVRAMI-MEHL-

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JOHNSTON’S MODEL FOR INTERPRETATION OF RESULTS ................. 194 9.6.1 K-A-M-J’s Model Applied To NAA Data ................................................ 196 9.6.2 K-A-M-J’s Model Applied To Virginia’s Data ......................................... 297 9.7 MODIFIED C 1260: CHANGING THE MOLARITY OF THE TESTING SOLUTION ........................................................................................................ 298 CHAPTER TEN – ASTM C 1293 RESULTS AND DISCUSSION 10.1 ASTM C 1293 ................................................................................................... 210 10.2 MODIFIED C 1293: PRISMS STORED IN A 1N NAOH SOLUTION AT 800C ........................................................................................................... 217 10.3 MODIFIED C 1293: PRISMS STORED IN A 1N NAOH SOLUTION AT 380C ........................................................................................................... 227 10.4 MODIFIED C 1293: PRISMS STORED OVER WATER, AT 100% R.H. AND 600C ................................................................................................... 235 10.5 SUMMARY: STANDARD AND MOFIFIED C 1293 TESTING PROCEDURES ........................................................................................... 241 CHAPTER ELEVEN – INVESTIGATION OF MITIGATION ALTERNATIVES USING ASTM C 1260 11.1 INTRODUCTION ............................................................................................ 243 11.2 EFFECT OF CLASS C FLY ASH USING C 1260 .......................................... 243 11.3 EFFECT OF CLASS F FLY ASH USING C 1260 ............................................ 249 11.4 EFFECT OF SILICA FUME USING C 1260 .................................................. 255 11.5 EFFECT OF GRANULATED SLAG USING C 1260 ...................................... 260 11.6 EFFECT OF CALCINED CLAY USING C 1260 ........................................... 266 11.7 EFFECT OF AIR ENTRAINMNT USING C 1260 ........................................... 274 11.8 EFFECT OF WATER-CEMENT RATIO USING C 1260 .............................. 279 11.9 EFFECT OF LITHIUM NITRATE (LiNO3) USING C 1260 ............................ 285 11.10 SUMMARY OF MITIGATION ALTERNATIVES INVESTIGATION USING C 1260 .............................................................................................. 292 11.11 EFFECTIVENESS OF THE MITIGATION ALTERNATIVES AT DIFFERENT CEMENT ALKALI CONTENT ............................................. 294 11.11.1 Effect of Class C Fly Ash Coupled with Various Cement Alkali Contents ................................................................................................ 305 11.11.2 Effect of Class F Fly Ash Coupled with Various Cement Alkali Contents ................................................................................................ 306 11.11.3 Effect of Granulated Slag Coupled with Various Cement Alkali Contents ................................................................................................ 307 11.11.4 Effect of Silica Fume Coupled with Various Cement Alkali Contents ................................................................................................ 308 11.11.5 Effect of Air Entrainment Coupled with Various Cement Alkali Contents ................................................................................................ 309 11.11.6 Effect of Calcined Clay Coupled with Various Cement Alkali Contents ................................................................................................ 309 11.12 EVALUATION OF THE MITIGATION ALTERNATIVES C 1260

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RESULTS USING K-A-M-J’S MODEL ....................................................... 310 11.13 EVALUATION OF THE MITIGATION ALTERNATIVES C 1260 RESULTS USING K-A-M-J’S MODEL ....................................................... 319 11.14 ASTM C 1260 INVESTIGATION OF MITIGATION ALTERNATIVES: SUMMARY ................................................................... 325 11.15 COMPARISON OF THE MITIGATION ALTERNATIVES ........................ 327 CHAPTER TWELVE – INVESTIGATION OF MITIGATION ALTERNATIVES USING ASTM C 1293 12.1 INTRODUCTION ............................................................................................ 331 12.2 INVESTIGATION OF MITIGATION ALTERNATIVES USING C 1293 ................................................................................................ 334 12.2.1 Effect Of Class C Fly Ash Using C 1293 ................................................ 334 12.2.2 Effect Of Class F Fly Ash Using C 1293 .................................................. 338 12.2.3 Effect Of Silica Fume Using C 1293 ....................................................... 342 12.2.4 Effect Of Granulated Slag Using C 1293 .................................................. 346 12.2.5 Effect Of Calcined Clay Using C 1293 ................................................... 350 12.2.6 Effect Of Lithium Nitrate (Lino3) Using C 1293 ...................................... 355 12.2.7 Effect Of Air Entrainmnt Using C 1293.................................................... 360 12.3 COMPARISON BETWEEN ONE YEAR C 1293 RESULTS AND 13-WEEK ACCELERATED C 1293 RESULTS ............................................ 367 12.4 INVESTIGATION OF MITIGATION ALTERNATIVES USING ACCELERATED C 1293 ................................................................. 368 12.4.1 Effect Class C Fly Ash Accelerated C 1293 ........................................... 369 12.4.2 Effect Class F Fly Ash Accelerated C 1293 .............................................. 373 12.4.3 Effect Silica Fume Accelerated C 1293 .................................................. 378 12.4.4 Effect Granulated Slag Accelerated C 1293 .............................................. 383 12.4.5 Effect Calcined Clay Accelerated C 1293 ............................................... 388 12.4.6 Effect Lithium Nitrate Accelerated C 1293 ............................................... 393 12.4.7 Effect Air Entrainmnt Accelerated C 1293 ............................................... 398 12.4.8 Effect Of Lowering The Cement Alkali Content Using Accelerated C 1293 ............................................................................... 403 12.4.9 Comparison Betwwn The Effectiveness Of The Different Mitigation Alternatives ............................................................................ 408 12.4.10 Summary Of The Evaluation Of The Mitigation Alternatives Using The Accelerated Concrete Prism Test ....................................... 411 12.5 INVESTIGATION OF MITIGATION ALTERNATIVES USING ACCELERATED c 1293 RESULTS AND CEMENTS WITH DIFFERENT Na2Oequiv. CONTENTS ...................................................................................... 413 12.6 SUMMARY AND SPECIFICATION ............................................................. 418 CHAPTER THIRTEEN – COMPARISON BETWEEN C 1260, C 1293, PETROGRAPHIC ANALYSIS, AND FIELD INVESTIGATION RESULTS 13.1 INTRODUCTION ............................................................................................ 420 13.2 ASTM C 1260, ASTM C 1293, PETROGRAPHIC EXAMINATION

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AND FIELD PERFORMANCE ....................................................................... 420 13.3 ASTM C 1260 MITIGATION ALTERNATIVES VS. C 1293 MITIGATION ALTERNATIVES ................................................................... 427

13.4 EVALUATING THE EFFECT OF CEMENT TOTAL ALKALI CONTENT USING ASTM C 1260 AND ACCELERATED C 1293 ............. 435 13.5 EVALUATING THE EFFECTIVENESS OF MITIGATION ALTERNATIVES WITH A 0.80% Na2Oequiv. CEMENT USING ASTM C 1260 AND ACCELERATED C 1293 ................................................ 437

CHAPTER FOURTEEN – GUIDELINES AND RECOMMENDATIONS 14.1 INTRODUCTION ............................................................................................ 438 14.2 PREDICTING THE POTENTIAL ALKALI-SILICA REACTIVITY OF AGGREGATES ......................................................................................... 439 14.2.1 Field Performance Record ....................................................................... 439 14.2.2 Laboratory Testing .................................................................................. 442 14.3 MINIMIZING POTENTIAL FOR ASR-RELATED DAMAGE ..................... 445 14.4 COST OF USING THE DIFFERENT MITIGATION ALTERNATIVES ............................................................................................... 448 14.5 CONCLUDING REMARKS ............................................................................ 449 CHAPTER FIFTEEN – SUMMARY OF CONCLUSIONS 15.1 INTRODUCTION ............................................................................................ 452 15.2 ASSESSING AGGREGATE REACTIVITY ................................................... 452 15.3 EFFECTIVE MITIGATION ALTERNATIVES .............................................. 456 15.4 FINAL REMARKS .......................................................................................... 463 APPENDIX A – EFFECT OF CHANGING THE CURING SOLUTION MOLARITY ON THE RESULTS OF ASTM C 1260 ...................... 464 APPENDIX B – VARIABLES FOR THE K-A-M-J MODEL USING C 1260 EXPANSIONS UP TO 28 DAYS ......................................................... 473 APPENDIX C - EFFECTIVE LEVELS OF CEMENT REPLACEMENT

WITH CLASS C FLY ASH, CLASS F FLY ASH, AND SILICA FUME EVALUATED USING THE K-M-A-J’S MODEL FOR A6-NM, A4-ID, A2-WY, C2-SD, AND B4-VA .……………...480

APPENDIX D – PETROGRAPHIC ANALYSIS AND FIELD PERFORMANCE DOCUMENTATION OF AGGREGATES ...................................... 484 REFERENCES ........................................................................................................... 501 VITA ........................................................................................................... 521

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LIST OF TABLES Table Page 3.1 Testing Methods for Potential Aggregate Reactivity .................................................... 25 3.2 Most Widely Used Aggregate Tests for Identifying ASR Reactivity ........................... 26 3.3 Alkali Contribution from Fly Ash: Concrete with Cristobalite ..................................... 38 3.4 Chemical Compositions of three Investigated Ashes .................................................... 39 3.5 Tallowa Dam Cement and Fly Ash Properties .............................................................. 42 3.6 Composition of Class C Fly Ashes (Kakodkar et al., 1997).......................................... 45 3.7 Composition of Selective Natural Pozzolans Tested By Johnston et al ........................ 48 3.8 Properties of Investigated Fly Ashes (Chen et al. 1993) ............................................... 51 3.9 Properties of Investigated Silica Fume, Natural Pozzolan, and Slag ............................ 51 3.10 Effective Levels of Replacements for Materials Effective in Mitigating the ASR Damage .................................................................................................................. 52 3.11 Example for Specifying Fly Ash with Reactive Aggregates ....................................... 56 3.12 Slag Specification Example ......................................................................................... 57 4.1 Survey Results (published by RILEM in 1996) .......................................................... 61 4.2 Classification of Aggregates by Different Test Methods (Shayan 1992) .................... 66 4.3 Properties of Aggregates Investigated (Fournier, Bilodeau, and Malhotra 1994) ....... 74 4.4 Proposed Limits for different Testing Conditions (Fournier et al. 1994) .................... 75 4.5 Recommended Procedures and Limits to Detect Alkali-Reactive Aggregates (Berube 1992) ........................................................................................... 79 4.6 Maximum Alkali Content (Tang et al., 1996) ............................................................. 82 4.7 Summary of the Different AFNOR Testing Procedures (Le Roux et al. 1996) .......... 85 4.8 Level of Prevention as Determined by the Category and Exposure of the Structure (Le Roux et al. 1996) .......................................................................................................... 86 4.9 Methodology Used for Level B Prevention (Le Roux et al. 1996) ............................. 87 4.10 Aggregate Sources Investigated Throughout the Study (Starks 1993) ..................... 105 4.11 Results of the C 1260 Test (Starks, 1993) ................................................................. 107 4.12 Investigated Aggregate Source, Field Performance, and C 227 Results (Lane, 1994)110 4.13 Recommended Testing Procedures and Limits (Mid-Atlantic RTC, 1993) .............. 113 4.14 Recommended Mitigation Alternatives and Methods of Validation (RTC 1993) ... 113 4.15 Recommended Testing Procedures and Limits (Lead State Team, 1999) ................. 114 4.16 Recommended Mitigation Alternatives and Methods of Validation (Lead State Team, 1999) ............................................................................................................. 115 4.17 C 1260 and C 1293 Results of Testing Performed by NAA (NAA, 1999) ............... 118 4.18 Alkali Content Groups (Chatterji et al. 1992) ........................................................... 119 4.19 Sand Classification (Chatterji et al. 1992) ................................................................. 120 4.20 Coarse Aggregate Classification (Chatterji et al. 1992) ............................................ 120 4.21 Specifications for Concrete (Chatterji et al. 1992) .................................................... 121 5.1 Aggregates Representing the Complete Spectrum of ASR Reactivity ...................... 123 5.2 Aggregates and Aggregate Sources Selected for the Study ...................................... 125 5.3 Chemical and Physical Properties of Type I/II Cement with High Alkali Content ... 127 5.4 Chemical and Physical Properties of Type I/II Cement with Low Alkali Content ... 128 5.5 Chemical Properties of Granualted Slag ................................................................... 128 5.6 Chemical and Physical Properties of Calcined Clay ................................................. 129

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5.7 Chemical and Physical Properties of the Class C Fly Ash ........................................ 130 5.8 Chemical and Physical Properties of the Class F Fly Ash ........................................ 130 5.9 Properties of Chemical Admixtures .......................................................................... 131 6.1 Aggregate Testing Performed .................................................................................... 132 6.2 ASTM C 227 and C1260 Aggregate Grading Requirements .................................... 133 6.3 ASTM C 1293 Coarse Aggregate Grading Requirements ........................................ 133 6.4 Aggregates and Test Combinations Used to Investigate Mitigation Alternatives ..... 148 6.5 Summary of the Testing Program .............................................................................. 149 7.1 Proportions and Mortar Properties for C 227 Mixtures ............................................. 150 7.2 Mortar Mixtures Used for ASTM C 1260, C 1260M1, C 1260M2, C 1260 M3, AND C 1260M4 ........................................................................................................ 151 7.3 Mortar Mixtures Used to Evaluate the Effect of Class C Fly Ash ............................ 152 7.4 Mortar Mixtures Used to Evaluate the Effect of Class F Fly Ash ............................. 153 7.5 Mortar Mixtures Used to Evaluate the Effect of Silica Fume ................................... 153 7.6 Mortar Mixtures Used to Evaluate The Effect of Granulated Slag ........................... 154 7.7 Mortar Mixtures Used to Evaluate the Effect of Lithium Nitrate ............................. 155 7.8 Mortar Mixtures Used to Evaluate the Effect of Entrained Air ................................ 156 7.9 Mortar Mixtures Used to Evaluate the Effect Calcined Clay .................................... 157 7.10 Mortar Mixtures Used to Evaluate the Effect of W/C ............................................... 158 7.11 Mortar Mixtures Used to Count for the Absorption of Aggregates .......................... 159 7.12 Concrete Mix Proportions for ASTM C 1293 and Modified C 1293 ........................ 161 7.13 Concrete Mixtures Used to Investigate the Effect of Air Entrainment ..................... 162 7.14 Concrete Mixtures Used to Investigate the Effect of Silica Fume ............................ 163 7.15 Concrete Mixtures Used to Investigate the Effect of Class C Fly Ash ..................... 164 7.16 Concrete Mixtures Used to Investigate the Effect of Class F Fly Ash ...................... 165 7.17 Concrete Mixtures Used to Investigate the Effect of Granulated Slag ...................... 166 7.18 Concrete Mixtures Used to Investigate the Effect of Calcined Clay ......................... 167 7.19 Concrete Mixtures Used to Investigate the Effect of Lithium Nitarte ....................... 168 8.1 Physical Properties of Aggregates investigated ........................................................ 170 8.2 Chemical Analysis of Aggregates ............................................................................. 171 8.3 Summary of Available Documentation on Aggregates Investigated ........................ 172 8.4 ASTM C 227 Expansion Results for Aggregates investigated .................................. 173 9.1 ASTM C 1260 Expansion Test Results ..................................................................... 179 9.2 ASTM C 1260 Performed by NAA ........................................................................... 183 9.3 Differences Between NAA Results and Results Generated in this Study ................. 183 9.4 Variations from the Mean of the NAA and the C 1260 Results Generated Through this Study .................................................................................. 184 9.5 Expansions up to 56 days in 1N NaOH Curing Solution .......................................... 185 9.6a C 1260 Expansions for Mixtures Adjusted for Aggregate Absorption ..................... 190 9.6b Expansions of Category A Aggregates (Different Molarity Solutions) .................... 199 9.7 Expansions of Category B, C, & D Agg. (Different Molarity Solutions) ................. 200 9.8 Expansions of Category E Aggregates (Different Molarity Solutions) ..................... 201 9.9 14-Day Expansions of the different Testing Solutions .............................................. 202 9.10 Effect of Na2Oequiv. Content on ASR Using ASTM C 1260 ...................................... 208 10.1 ASTM C 1293 Results for Category A Aggregates .................................................. 211

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10.2 ASTM C 1293 Results for Category B, C, & D Aggregates ............................................ 211 10.3 Standard ASTM C 1293 Results for Category E Aggregates .................................. 212 10.4 Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category A Aggregates ................................................................................................................ 217 10.5 Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category B, C, & D Aggregates ............................................................................................... 218 10.6 Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category E Aggregates ................................................................................................................ 218 10.7 Summary of Generated Results: ASTM C 1293 vs 1N NaOH at 800C Using Respectively 0.040% at one-year and 0.040% at Four-Week as Failure Criteria .... 223 10.8 Summary of Generated Results: ASTM C 1293 vs 1N NaOH at 800C Using Respectively 0.040% at one-year and 0.060% at 1-week as Failure Criteria .......... 225 10.9 Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category A Aggregates ................................................................................................................ 227 10.10 Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category B, C, & D Aggregates ............................................................................................... 228 10.11 Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category E Aggregates ................................................................................................................ 228 10.12 Summary of Generated Results: ASTM C 1293 vs 1N NaOH at 800C Using Respectively 0.040% at one-year and 0.040% at 26-week as Failure Criteria ........ 233 10.13 Expansions of Category A Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C ...................................................................... 235 10.14 Expansions of Category B, C, & D Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C ........................................................................................... 235 10.15 Expansions of Category E Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C ........................................................................................... 236 10.16 Summary of Generated Results: ASTM C 1293 vs C 1293 at 600C Using Respectively 0.040% at one-year and 0.040% at 13-week as Failure Criteria ........ 239 10.17 Expansion Limits for the Different C 1293 Procedures ........................................... 241 10.18 Aggregate’s Reactivity Classification for the Different C 1293 Procedures ............ 241 10.19 Summary Results of the Different C 1293 Procedures ............................................. 242 11.1 C 1260 Expansions Using Class C Fly Ash ............................................................. 244 11.2 Effect of Class C Fly Ash on the 14-Day C 1260 Expansions ................................. 249 11.3 C 1260 Expansions Using Class F Fly Ash .............................................................. 250 11.4 Effect of Class F Fly Ash on the 14-Day C 1260 Expansions ................................. 254 11.5 C 1260 Expansions Using Silica Fume .................................................................... 255 11.6 Effect of Silica Fume on the 14-Day C 1260 Expansions ........................................ 260 11.7 C 1260 Expansions Using Granulated Slag.............................................................. 261 11.8 Effect of Granulated Slag on the 14-Day C 1260 Expansions ................................. 266 11.9 C 1260 Expansions Using Calcined Clay ................................................................. 267 11.10 Category E C 1260 Expansions Using Calcined Clay .............................................. 272 11.11 Effect of Calcined Clay on the 14-Day C 1260 Expansions .................................... 273 11.12 C 1260 Expansions Using Air Entrainment ............................................................. 274 11.13 Effect of Air Entrainment on the 14-Day C 1260 Expansions ................................. 279 11.14 C 1260 Expansions Using Various Water-Cement Ratios ....................................... 280

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11.15 C 1260 Expansions Using Different LiNO3 Dosages ............................................... 286 11.16 Effect of LiNO3 on the 14-Day C 1260 Expansions ................................................ 291 11.17 Effectiveness of the Mitigation Alternatives Using the 14-day of 0.10% Criteria .......................................................................................... 293 11.18 Expansion Results of A6-NM Used with Mitigation Alternatives at Different Cement Alkali Content ............................................................................. 295 11.19 Exposure Solution Normalities Investigated and Their Corresponding Na2Oequiv. content and Recommended Expansion Limits .......................................................... 305 11.20 Effectiveness of Class C Fly Ash at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day) ............................ 306 11.21 Effectiveness of Class F Fly Ash at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day) ............................ 307 11.22 Effectiveness of Granulated Slag at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day) ............................ 308 11.23 Effectiveness of Silica Fume at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day) ............................ 308 11.24 Effectiveness of Air Entrainment at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day) ............................ 309 11.25 Effectiveness of Calcined Clay at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day) ............................ 310 11.26 Mitigation Alternatives Results Using K-A-M-J’s Ln (k) = -6 ................................ 318 11.27 Predicted Levels of Replacement Using the K-M-A-J’s Model ............................... 319 11.28 C 1260 Expansions of Some Predicted Values of the K-M-A-J’s Model ................ 320 11.29 Effective ASR Mitigation Alternatives When Evaluating Aggregates Using ASTM C 1260 with 1N NaOH Solution (1.5% Na2Oequiv.) ....................................... 327 11.30 Effective ASR Mitigation Alternatives for Highly Reactive Aggregate A6-NM (C1260 14-day of 0.92%) Evaluated Using C 1260 with 0.75N, 0.50N, & 0.35N NaOH Solutions ................................................................. 326 12.1 Aggregates Used for Mitigation Alternative Investigation ...................................... 333 12.2 C 1293 Expansions Using Class C Fly Ash ............................................................. 335 12.3 Effect of Class C Fly Ash on ASR Using C 1293 .................................................... 338 12.3a C 1293 Expansions Using Class F Fly Ash .............................................................. 341 12.4 Effect of Class F Fly Ash on ASR Using C 1293 .................................................... 342 12.5 C 1293 Expansions Using Silica Fume .................................................................... 343 12.6 Effect of Silica Fume on ASR Using C 1293 ........................................................... 346 12.7 C 1293 Expansions Using Granulated Slag.............................................................. 347 12.8 Effect of Granulated Slag on ASR Using C 1293 .................................................... 350 12.9 C 1293 Expansions Using Granulated Slag.............................................................. 351 12.10 Effect of Calcined Clay on ASR Using C 1293 ....................................................... 354 12.11 C 1293 Expansions Using Lithium Nitrate .............................................................. 356 12.12 Effect of Lithium Nitrate on ASR Using C 1293 ..................................................... 359 12.13 C 1293 Expansions Using Air Entrainment ............................................................. 363 12.14 Effect of Air Entrainment on ASR Using C 1293 .................................................... 364 12.15 Additional C 1293 Expansions Using Air Entrainment ........................................... 365 12.16 Accelerated C 1293 Expansions Using Class C Fly Ash ......................................... 372

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12.17 Effect of Class C Fly Ash on ASR Using Accelerated C 1293 ................................ 373 12.18 Accelerated C 1293 Expansions Using Class F Fly Ash .......................................... 374 12.19 Effect of Class F Fly Ash on ASR Using Accelerated C 1293 ................................ 378 12.20 Accelerated C 1293 Expansions Using Silica Fume ................................................ 379 12.21 Effect of Silica Fume on ASR Using Accelerated C 1293 ....................................... 383 12.22 Accelerated C 1293 Expansions Using Granulated Slag .......................................... 384 12.23 Effect of Granulated Slag on ASR Using Accelerated C 1293 ................................ 388 12.24 Accelerated C 1293 Expansions Using Granulated Slag .......................................... 389 12.25 Effect of Calcined Clay on ASR Using Accelerated C 1293 ................................... 393 12.26 Accelerated C 1293 Expansions Using Lithium Nitrate .......................................... 394 12.27 Effect of Lithium Nitrate on ASR Using Accelerated C 1293 ................................. 398 12.28 Accelerated C 1293 Expansions Using Air Entrainment ......................................... 399 12.29 Effect of Air Entrainment on ASR Using Accelerated C 1293 ................................ 403 12.30 Accelerated C 1293 Expansions Using Different Cement Na2Oequiv. Contents ........ 404 12.31 Effect of Na2Oequiv. Content on ASR Using Accelerated C 1293 ............................. 408 12.32 Effectiveness of the Mitigation Alternatives Using the Accelerated C 1293 Criteria .. 412 12.33 Accelerated C 1293 Expansions of Aggregate A6-NM Using Different Mitigation Alternatives and 0.80% Na2Oequiv. Content Cement ................................ 414 12.34 Effectiveness of Different Mitigation Alternatives Using The Accelerated C 1293 with Aggregate A6-NM and 0.80% Na2Oequiv. Cement ............ 417 12.35 Effective ASR Mitigation Alternatives When Evaluating Aggregates Using Accelerated C 1293 at 600C ........................................................ 418 12.36 Effective ASR Mitigation Alternatives for Highly Reactive Aggregate A6-NM (Accelerated C 1293 13-week of 0.407%) Evaluated Using Accelerated C 1293 (600C) with 0.80% Na2Oequiv. Cement ...................................... 419 13.1 C 1260 14-Day Expansions and C 1293 52-Week Expansions ............................... 421 13.2 Expansion Limits Used to Evaluate Effectiveness of Mitigation Alternatives ........ 427 13.3 Effectiveness of Mitigation Alternatives with Aggregate A4-ID Evaluated Using C 1260 and Accelerated C 1293 .................................................... 428 13.4 Effectiveness of Mitigation Alternatives with Aggregate A2-WY Evaluated Using C 1260 and Accelerated C 1293 .................................................... 429 13.5 Effectiveness of Mitigation Alternatives with Aggregate C2-SD Evaluated Using C 1260 and Accelerated C 1293 .................................................... 430 13.6a Effect of Na2Oequiv. Content on ASR Using ASTM C 1260 ..................................... 436 13.6b Effect of Na2Oequiv. Content on ASR Using Accelerated C 1293 ............................. 436 13.7 Effective ASR Mitigation Alternatives for Highly Reactive Aggregate A6-NM (C1260 14-day of 0.92%) Evaluated Using a Cement Alkali Content of 0.80% Na2Oequiv. .. 438 14.1 Expansion Limits for Identifying Potentially Alkali-Silica Reactive Aggregates .... 444 14.2 Determination of the Degree of Alkali-Silica Reactivity of Aggregates .................. 444 14.3 Price Cost of Materials Used Throughout Investigation .......................................... 448 14.4 Cost of Using The Mitigation Alternatives for a Cementitious Material Content of 710 lb/yd3 ................................................................................................ 449 15.1 Effectiveness of the Mitigation Alternatives Using the 14-Day C 1260 Test with 0.10% Criteria ................................................................. 456 15.2 Effective ASR Mitigation Alternatives for Highly Reactive

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Aggregate A6-NM (C1260 14-Day Expansion of 0.92%) Evaluated with 0.75N, 0.50N, & 0.35N NaOH Solutions ......................................................... 457 15.3 Effectiveness of the Mitigation Alternatives Using the Accelerated C 1293 Criteria ...................................................................................... 459 15.4 Effective ASR Mitigation Alternatives .................................................................... 461 15.5 Effective ASR Mitigation Alternatives for Highly Reactive Aggregate A6-NM (ASTM C 1293 one-year expansion of 0.411%) Using 0.80% Na2Oequiv. Cement ... 462

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LIST OF FIGURES

Figure Page 1.1 Results of the DOT Survey ........................................................................................... 2 2.1 Silicon Tetrahedron (Silica) ........................................................................................ 12 2.2 Quartz structure (SiO2) (Crystalline Structure) ............................................................ 12 2.3 Effect of Silica Content On ASR................................................................................... 14 3.1 Effect of alkali content (% Na2Oeq) in the ASTM C 227 mortar bar method (Siliceous limestone from Ottawa, Ontario) ................................................................. 19 3.2 Effect of water-cement ratio in the ASTM C 227 mortar bar method (Siliceous Limestone from Trois-Rivieres, Quebec) .................................................................... 20 3.3 Comparison Between ASTM C 1260 and ASTM C 1293 Results Illustrating the Severity of ASTM C 1260 ..................................................................................... 21 3.4 Effect of Aggregate Reactivity and Percent Fly Ash Replacement on the Effective Alkali Contribution from Fly Ash ................................................................ 33 3.5 Effect of Aggregate Reactivity Effective Alkali Contribution from Fly Ash ............... 34 3.6 Using 25% Class F Fly Ash to Prevent Cracking of Concrete Made with a Moderately Reactive Aggregate (flint)......................................................................... 35 3.7 Effect of Using 6% Class F Fly Ash with a Moderately Reactive Aggregate (flint) 35 3.8 Effect of Class F Fly Ash on Cracking of Concrete Made with a Highly Reactive Aggregate ...................................................................................................... 36 3.9 Effect of Class F Fly Ash on Expansions of Concrete Containing a Highly Reactive Aggregate (Cristobalite) ................................................................................ 38 3.10 Effect of Replacement Levels of Fly Ash A on ASR Expansions .............................. 40 3.11 Effect of Replacement Levels of Fly Ash B on ASR Expansions ............................... 40 3.12 Effect of Replacement Levels of Fly Ash F on ASR Expansions ............................... 41 3.13 Expansion Curves for Concrete Cores Taken from Several Locations of the Dam and Stored in a 1M NaOH Solution at 400C .................................................. 43 3.14 ASTM C 1260 vs. Replacement Levels of Cement with Class F Fly Ash .................. 44 3.15 Comparison of 14-Dya Expansions of Mortar Bars Made with the Different Fly Ashes and a Slowly Reactive Aggregate ................................................ 46 3.16 Comparison of 14-Dya Expansions of Mortar Bars Made with the Different Fly Ashes and a Highly Reactive Aggregate ................................................ 46 3.17 Effect of Class F Fly Ash on the 14-Day Expansions of Mortar Bars Made with a Highly Reactive Aggregates and Tested Using ASTM C 1260 ...................... 47 3.18 Effect of Selective Natural Pozzolans on the 14-Day Expansions of Mortar Bars Made with a Highly Reactive Aggregates and Tested Using C 1260 ................ 49 3.19 Expansions of Concrete Prisms Made Using a Cement with 1.13% alkalis, a Reactive Aggregate (Spratt), and 58% Class F Fly Ash. Prisms were Stored in a 1M NaOH Solution at 380C ................................................................................. 50 3.20 C 227 Expansion after 6 Months for Specimens Made with Multiple Replacement Levels ................................................................................................... 54 4.1 Decision Chart for Determining the Potential ASR of ConcreteAggregates ................. 80 4.2 Flowchart of Testing Procedures Used to Evaluate Aggregate Reactivity .................... 91

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4.3 Failure Criteria for Determining Safe Cement Alkali Level for Deleterious Aggregates .............................................................................................. 108 4.4 Flow Chart Suggested by PCA .................................................................................... 116 5.1 Locations of the Selected Aggregate Sources ........................................................... 124 6.1 Aggregate Washing Over #100 Sieve ....................................................................... 134 6.2 Sieve Sizes Required For C 227 and C 1260 Mortar Bars .......................................... 134 6.3 Mortar bars cured for 24 hours in a moisture room, immediately after being formed (C 227 and C 1260)........................................................................................ 136 6.4 Mortar bars stored over water, in containers with no wicks, in an environmental

room at 380C …………………………...…………………………………………..136 6.5 First Step in Performing ASTM C 227........................................................................ 137 6.6 Second Step in Performing ASTM C 227 ................................................................... 138 6.7 Mortar bars stored in a 1N NaOH solution used for C 1260 ....................................... 140 6.8 Mortar bars stored in an oven at 800C, in 1N NaOH solutions (C 1260

requirements) …………………………………………………………………140 6.9 ASTM C 1260 Procedures .......................................................................................... 141 6.10 Concrete prisms stored over water, in 6-gal buckets with wicks, in an environmental room at 380C..................................................................................... 143 6.11 C 1293 buckets stored for 16 h in a moisture room before measuring scheduled expansion readings ................................................................. 144 6.12 Top view of a C 1293 bucket; Concrete prisms over water; Wicks on the sides; Seal cover ................................................................................. 144 6.13 Concrete prism being measured for expansion .......................................................... 144 6.14 Aggregate Preparation for C 1293 ............................................................................. 145 6.15 C 1293 Concrete Prism Procedures ........................................................................... 146 8.1 ASTM C 227 Results for Category A Aggregates ..................................................... 174 8.2 ASTM C 227 Results of Category B, C, & D Aggregates ......................................... 174 8.3 ASTM C 227 Results for Category E Aggregates ...................................................... 175 9.1 ASTM C 1260 Expansions for Category A Aggregates ............................................ 180 9.2 ASTM C 1260 Expansions for Category B, C, & D Aggregates ............................... 180 9.3 ASTM C 1260 Expansions for Category E Aggregates ............................................. 181 9.4 Comparison Between the 14-Day Expansions Generated for the ASTM C 1260 and for the 56-Day Extended ASTM C 1260 ............................................................. 186 9.5 56-Day C 1260 Results for Category A Aggregates .................................................. 187 9.6 56-Day C 1260 Results for Category B, C, & D Aggregates ..................................... 187 9.7 56-Day C 1260 Results for Category E Aggregates ................................................... 188 9.8 Modified Water C 1260 Expansions for Category A Aggregates .............................. 191 9.9 Modified Water C 1260 Expansions for Category B, C, & D Aggregates ................. 191 9.10 Modified Water C 1260 Expansions for Category E Aggregates ............................ 192 9.11 Polynomial Regression Coefficients A1 vs. A2 ........................................................ 193 9.12a Avrami’s Exponent M versus ln(k) illustrating Avrami’s Equation ....................... 195 9.12b K-A-M-J’s Model Results For NAA C 1260 Data ................................................. 196 9.12c K-A-M-J’s Model Results For Virginia Aggregates .............................................. 197 9.13 14-Day Expansion Comparison Between Different Curing Solutions, Category A Aggregates ..................................................................................................... 203

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9.14 14-Day Expansion Comparison Between Different Curing Solutions Category B, C, & D Aggregates .............................................................................. 203 9.15 14-Day Expansion Comparison Between Different Curing Solutions Category

E Aggregates ………………………………………………………………..204 9.16 Category A Results at Different Solution Normalities and Cement Alkali Content ........................................................................................... 205 9.17 Category B, C, & D Results at Different Solution Normalities and Cement Alkali Content ................................................................. 205 9.18 Category E Results at Different Solution Normalities and Cement Alkali Content ..................................................................................... 206 10.1a ASTM C 1293 Results for Category A Aggregates ............................................... 212 10.1b ASTM C 1293 Results for Coarse Aggregates of Category A ............................... 213 10.1c ASTM C 1293 Results for Fine Aggregates of Category A ................................... 213 10.2 ASTM C 1293 Results for Category B, C, & D Aggregates .................................... 214 10.3 ASTM C 1293 Results for Category E Aggregates .................................................. 214 10.4 Comparison Between the 12-month Expansions of Tested Coarse and Fine Aggregates from the Same Source ........................................................................... 215 10.5a 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category A Aggregates .......................................................... 219 10.5b Four-Week Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category A Aggregates ........................................................................... 219 10.6a 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category B, C, and D Aggregates ......................................... 220 10.6b Four-Week Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category B, C, and D Aggregates ........................................................... 220 10.7a 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category E Aggregates ......................................................... 221 10.7b Four-Week Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category E Aggregates ........................................................................... 221 10.8 Comparison Between the Standard C 1293 procedures and Modified C 1293 Storing Prisms in 1N NaOH at 800C ....................................................................... 226 10.9a 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category A Aggregates ......................................................... 229 10.9b 13-Week (6-Month) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category A Aggregates ......................................................... 229 10.10a 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category B, C, & D Aggregates ......................................... 230 10.10b 13-Week (6-month) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category B, C, & D Aggregates ........................................... 230 10.11a 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category E Aggregates ....................................................... 231 10.11b 13-Week (6-month) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category E Aggregates ....................................................... 231 10.12 Comparison Between the Standard C 1293 procedures and Modified C 1293 Storing Prisms in 1N NaOH at 380C ..................................................................... 234

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10.13 Expansions of Category A Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C .................................................................... 236 10.14 Expansions of Category B, C, & D Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C ............................................................................. 237 10.15 Expansions of Category E Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C ............................................................................................ 237 10.16 Comparison Between the Standard C 1293 procedures and Modified C 1293 at 600C ................................................................................................... 240 11.1 Effect of Class C Fly Ash on C 1260 Expansions of Aggregate A2-WY .............................................................................................. 245 11.2 Effect of Class C Fly Ash on C 1260 Expansions of Aggregate A4-ID ................................................................................................. 245 11.3 Effect of Class C Fly Ash on C 1260 Expansions of Aggregate A6-NM ............................................................................................... 246 11.4 Effect of Class C Fly Ash on C 1260 Expansions of Aggregate B4-VA ................................................................................................ 246 11.5 Effect of Class C Fly Ash on C 1260 Expansions of Aggregate C2-SD ................................................................................................ 247 11.6 Effect of Class C Fly Ash on C 1260 Expansions of Aggregate E2-IA ................................................................................................. 247 11.7 Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Class C Fly Ash Replacement ........................................................ 248 11.8 Effect of Class F Fly Ash on C 1260 Expansions of Aggregate A2-WY .............................................................................................. 250 11.9 Effect of Class F Fly Ash on C 1260 Expansions of Aggregate A4-ID ................................................................................................. 251 11.10 Effect of Class F Fly Ash on C 1260 Expansions of Aggregate A6-NM ............................................................................................... 251 11.11 Effect of Class F Fly Ash on C 1260 Expansions of Aggregate B4-VA ................................................................................................ 252 11.12 Effect of Class F Fly Ash on C 1260 Expansions of Aggregate C2-SD ................................................................................................ 252 11.13 Effect of Class F Fly Ash on C 1260 Expansions of Aggregate E2-IA ................................................................................................. 253 11.14 Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Class F Fly Ash Replacement ......................................................... 253 11.15 Effect of Silica Fume on C 1260 Expansions of Aggregate A2-WY ................... 256 11.16 Effect of Silica Fume on C 1260 Expansions of Aggregate A4-ID ..................... 256 11.17 Effect of Silica Fume on C 1260 Expansions of Aggregate A6-NM ................... 257 11.18 Effect of Silica Fume on C 1260 Expansions of Aggregate B4-VA .................... 257 11.19 Effect of Silica Fume on C 1260 Expansions of Aggregate C2-SD ..................... 258 11.20 Effect of Silica Fume on C 1260 Expansions of Aggregate E2-IA ...................... 258 11.21 Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Silica Fume Replacement ............................................................... 259 11.22 Effect of Granulated Slag on C 1260 Expansions of

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Aggregate A2-WY .............................................................................................. 262 11.23 Effect of Granulated Slag on C 1260 Expansions of Aggregate A4-ID ................................................................................................. 262 11.24 Effect of Granulated Slag on C 1260 Expansions of Aggregate A6-NM ............................................................................................... 263 11.25 Effect of Granulated Slag on C 1260 Expansions of Aggregate B4-VA ................................................................................................ 263 11.26 Effect of Granulated Slag on C 1260 Expansions of Aggregate C2-SD ................................................................................................ 264 11.27 Effect of Granulated Slag on C 1260 Expansions of Aggregate E2-IA ................................................................................................. 264 11.28 Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Granulated Slag Replacement ......................................................... 265 11.29 Effect of Calcined Clay on C 1260 Expansions of Aggregate A2-WY ............... 268 11.30 Effect of Calcined Clay on C 1260 Expansions of Aggregate A4-ID .................. 268 11.31 Effect of Calcined Clay on C 1260 Expansions of Aggregate A6-NM ................ 269 11.32 Effect of Calcined Clay on C 1260 Expansions of Aggregate B4-VA ................ 269 11.33 Effect of Calcined Clay on C 1260 Expansions of Aggregate C2-SD ................. 270 11.34 Effect of Calcined Clay on C 1260 Expansions of Aggregate E2-IA .................. 270 11.35 Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Calcined Clay Replacement ............................................................ 271 11.36 Effect of Calcined Clay on the 14-Day C 1260 Expansions of Category E Aggregates ..................................................................................... 272 11.37 Effect of Air Entrainment on C 1260 Expansions of Aggregate A2-WY .............................................................................................. 275 11.38 Effect of Air Entrainment on C 1260 Expansions of Aggregate A4-ID ................................................................................................. 275 11.39 Effect of Air Entrainment on C 1260 Expansions of Aggregate A6-NM ............................................................................................... 276 11.40 Effect of Air Entrainment on C 1260 Expansions of Aggregate B4-VA ................................................................................................ 276 11.41 Effect of Air Entrainment on C 1260 Expansions of Aggregate C2-SD ................................................................................................ 277 11.42 Effect of Air Entrainment on C 1260 Expansions of Aggregate E2-IA ................................................................................................. 277 11.43 Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Entrained Air Levels ....................................................................... 278 11.44 Effect of W/C on C 1260 Expansions of Aggregate A2-WY ............................... 281 11.45 Effect of W/C on C 1260 Expansions of Aggregate A4-ID ................................. 281 11.46 Effect of W/C on C 1260 Expansions of Aggregate A6-NM ............................... 282 11.47 Effect of W/C on C 1260 Expansions of Aggregate B4-VA ................................ 282 11.48 Effect of W/C on C 1260 Expansions of Aggregate C2-SD ................................ 283 11.49 Comparison of the 14-Day C 1260 Expansions for the Different Water-Cement Ratios ............................................................................................ 283 11.50 Effect of LiNO3 on C 1260 Expansions of Aggregate A2-WY ........................... 287

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11.51 Effect of LiNO3 on C 1260 Expansions of Aggregate A4-ID .............................. 287 11.52 Effect of LiNO3 on C 1260 Expansions of Aggregate A6-NM ............................ 288 11.53 Effect of LiNO3 on C 1260 Expansions of Aggregate B4-VA ............................. 288 11.54 Effect of LiNO3 on C 1260 Expansions of Aggregate C2-SD ............................. 289 11.55 Effect of LiNO3 on C 1260 Expansions of Aggregate E2-IA .............................. 289 11.56 Comparison of the 14-Day C 1260 Expansions for the Different LiNO3 Dosages 290 11.57 Effect of Class C Fly Ash at Different Cement Alkali Contents for the Highly Reactive A6-NM ................................................................................................... 296 11.58 Effect of Class F Fly Ash at Different Cement Alkali Contents for the Highly Reactive A6-NM ................................................................................................... 297 11.59 Effect of granulated Slag at Different Cement Alkali Contents for the Highly Reactive A6-NM ................................................................................................... 297 11.60 Effect of Silica Fume at Different Cement Alkali Contents for the Highly Reactive A6-NM ................................................................................................... 298 11.61 Effect of Air Entrainment at Different Cement Alkali Contents for the Highly Reactive A6-NM ................................................................................................... 298 11.62 Effect of Calcined Clay at Different Cement Alkali Contents for the Highly Reactive A6-NM ................................................................................................... 299 11.63a Comparison of the 14-Day Expansions for the Combination of 35% Class C Fly Ash with Different Cement Alkali Contents ................................................... 300 11.63b Comparison of the 14-Day Expansions for the Combination of 25% Class C Fly Ash with Different Cement Alkali Contents ................................................... 300 11.64a Comparison of the 14-Day Expansions for the Combination of 20% Class F Fly Ash with Different Cement Alkali Contents ................................................... 301 11.64b Comparison of the 14-Day Expansions for the Combination of 15% Class F Fly Ash with Different Cement Alkali Contents ................................................... 301 11.65a Comparison of the 14-Day Expansions for the Combination of 50% Granulated Slag with Different Cement Alkali Contents ...................................... 302 11.65b Comparison of the 14-Day Expansions for the Combination of 25% Granulated Slag with Different Cement Alkali Contents ...................................... 302 11.66a Comparison of the 14-Day Expansions for the Combination of 10% Silica Fume with Different Cement Alkali Contents ............................................. 303 11.66b Comparison of the 14-Day Expansions for the Combination of 5% Silica Fume with Different Cement Alkali Contents ............................................. 303 11.67 Comparison of the 14-Day Expansions for the Combination of Air Entrainment with Different Cement Alkali Contents ...................................... 304 11.68 Comparison of the 14-Day Expansions for the Combination of Calcined Clay with Different Cement Alkali Contents ......................................... 304 11.69 Ln (K) values for Various Class C and Class F fly ash Replacement Levels Using 14-Day C 1260 Results ............................................................................... 311 11.70 Ln (K) values for Various Silica Fume and Granulated Slag Replacement Levels Using 14-Day C 1260 Results .............................................. 312 11.71 Ln (K) values for Various Calcined Clay and Lithium Nitrate Replacement Levels Using 14-Day C 1260 Results .............................................. 312

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11.72 M values for Various Air Entrainment Levels and Various Water-Cement Ratios Using 14-Day C 1260 Results ........................................... 313 11.73 M values for Various Class C and Class F fly ash Replacement Levels Using 14-Day C 1260 Results ............................................................................... 313 11.74 M values for Various Silica Fume and Granulated Slag Replacement Levels Using 14-Day C 1260 Results .............................................. 314 11.75 M values for Various Calcined Clay and Lithium Nitrate Replacement Levels Using 14-Day C 1260 Results .............................................. 314 11.76 M values for Various Air Entrainment Levels and Various Water-Cement Ratios Using 14-Day C 1260 Results ........................................... 315 11.77 Ln (K) vs. M Plot for the Class C and Class F Fly Ash C 1260 Results .................................................................................................... 315 11.78 Ln (K) vs. M Plot for the Silica Fume and Granulated Slag C 1260 Results .................................................................................................... 316 11.79 Ln (K) vs. M Plot for the Calcined Clay and LiNO3 C 1260 Results .................................................................................................... 316 11.80 Ln (K) vs. M Plot for the Air Entrainment and Various W/C C 1260 Results .................................................................................................... 317 11.81 Effectiveness of K-M-A-J Model Predictions for Aggregate A2-WY ................... 321 11.82 Effectiveness of K-M-A-J Model Predictions for Aggregate A4-ID ..................... 321 11.83 Effectiveness of K-M-A-J Model Predictions for Aggregate A6-NM ................... 322 11.84 Effectiveness of K-M-A-J Model Predictions for Aggregate B4-VA .................... 322 11.85 Effectiveness of K-M-A-J Model Predictions for Aggregate C2-SD ..................... 323 11.86 Comparison Between the 14-Day C 1260 expansions of Aggregates with 0% Replacement and with Predicted Replacements .................................................... 323 11.87 Mitigation Alternatives Used with Aggregate A6-NM .......................................... 328 11.88 Mitigation Alternatives Used with Aggregate A4-ID ............................................ 328 11.89 Mitigation Alternatives Used with Aggregate A2-WY .......................................... 329 11.90 Mitigation Alternatives Used with Aggregate C2-SD ............................................ 329 11.91 Mitigation Alternatives Used with Aggregate B4-VA ........................................... 330 11.92 Mitigation Alternatives Used with Aggregate E2-IA ............................................. 330 12.1 Summary of the Investigation of Mitigation Alternatives Using C 1293 and Accelerated C 1293 ................................................................. 332 12.2 Effect of Class C Fly Ash on C 1293 Expansions of Aggregate A4-ID ................................................................................................. 336 12.3 Effect of Class C Fly Ash on C 1293 Expansions of Aggregate A2-WY .............................................................................................. 336 12.4 Effect of Class C Fly Ash on C 1293 Expansions of Aggregate C2-SD ................................................................................................ 337 12.5 Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Class C Fly Ash Replacement ..................................... 337 12.6 Effect of Class F Fly Ash on C 1293 Expansions of Aggregate A4-ID ................................................................................................. 339 12.7 Effect of Class F Fly Ash on C 1293 Expansions of Aggregate A2-WY .............................................................................................. 339

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12.8 Effect of Class F Fly Ash on C 1293 Expansions of Aggregate C2-SD ................................................................................................ 340 12.9 Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Class F Fly Ash Replacement ...................................... 340 12.10 Effect of Silica Fume on C 1293 Expansions of Aggregate A4-ID ..................... 344 12.11 Effect of Silica Fume on C 1293 Expansions of Aggregate A2-WY ................... 344 12.12 Effect of Silica Fume on C 1293 Expansions of Aggregate C2-SD ..................... 345 12.13 Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Silica Fume Replacement ............................................ 345 12.14 Effect of Slag on C 1293 Expansions of Aggregate A4-ID ................................. 348 12.15 Effect of Slag on C 1293 Expansions of Aggregate A2-WY ............................... 348 12.16 Effect of Slag on C 1293 Expansions of Aggregate C2-SD ................................. 349 12.17 Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Slag Replacement ........................................................ 349 12.18 Effect of Calcined Clay on C 1293 Expansions of Aggregate A4-ID .................. 352 12.19 Effect of Calcined Clay on C 1293 Expansions of Aggregate A2-WY ............... 352 12.20 Effect of Calcined Clay on C 1293 Expansions of Aggregate C2-SD ................. 353 12.21 Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Calcined Clay Replacement ......................................... 353 12.22 Effect of Lithium Nitrate on C 1293 Expansions of Aggregate A4-ID ................ 357 12.23 Effect of Lithium Nitrate on C 1293 Expansions of Aggregate A2-WY ............. 357 12.24 Effect of Lithium Nitrate on C 1293 Expansions of Aggregate C2-SD ............... 358 12.25 Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Lithium Nitrate Replacement ...................................... 358 12.26 Effect of Air Entrainment on C 1293 Expansions of Aggregate A4-ID .............. 360 12.27 Effect of Air Entrainment on C 1293 Expansions of Aggregate A2-WY ............ 361 12.28 Effect of Air Entrainment on C 1293 Expansions of Aggregate C2-SD .............. 361 12.29 Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Air Entrainment Contents ............................................................ 362 12.30 Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Air Entrainment Contents of Table 12.15 ................................... 366 12.31 Comparison Between the Standard One-Year Expansions and the Accelerated 13-Week Expansions of the Various Mitigation Alternatives ............................... 367 12.32 Effect of Class C Fly Ash on the Accelerated C 1293 Expansions of Aggregate A4-ID ................................................................................................. 369 12.33 Effect of Class C Fly Ash on the Accelerated C 1293 Expansions of Aggregate A2-WY .............................................................................................. 370 12.34 Effect of Class C Fly Ash on the Accelerated C 1293 Expansions of Aggregate C2-SD ................................................................................................ 370 12.35 Effect of Class C Fly Ash on the Accelerated C 1293 Expansions of Aggregate E2-IA ................................................................................................. 371 12.36 Comparison Between the 26-Week Expansions Generated Using Accelerated C 1293 Procedures and the Different Class C Fly Ash Replacement ................... 371 12.37 Effect of Class F Fly Ash on the Accelerated C 1293 Expansions of Aggregate A4-ID ................................................................................................. 375

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12.38 Effect of Class F Fly Ash on the Accelerated C 1293 Expansions of Aggregate A2-WY .............................................................................................. 375 12.39 Effect of Class F Fly Ash on the Accelerated C 1293 Expansions of Aggregate C2-SD ................................................................................................ 376 12.40 Effect of Class F Fly Ash on the Accelerated C 1293 Expansions of Aggregate E2-IA ................................................................................................. 376 12.41 Comparison Between the 26-Week Expansions Generated Using Accelerated C 1293 Procedures and the Different Class F Fly Ash Replacement .................... 377 12.42 Effect of Silica Fume on the Accelerated C 1293 Expansions of Aggregate A4-ID ................................................................................................. 380 12.43 Effect of Silica Fume on the Accelerated C 1293 Expansions of Aggregate A2-WY .............................................................................................. 380 12.44 Effect of Silica Fume on the Accelerated C 1293 Expansions of Aggregate C2-SD ................................................................................................ 381 12.45 Effect of Silica Fume on the Accelerated C 1293 Expansions of Aggregate E2-IA ................................................................................................. 381 12.46 Comparison Between the 26-Week Expansions Generated Using Accelerated C 1293 Procedures and the Different Silica Fume Replacement .......................... 382 12.47 Effect of Granulated Slag on the Accelerated C 1293 Expansions of Aggregate A4-ID ................................................................................................. 385 12.48 Effect of Granulated Slag on the Accelerated C 1293 Expansions of Aggregate A2-WY .............................................................................................. 385 12.49 Effect of Granulated Slag on the Accelerated C 1293 Expansions of Aggregate C2-SD ................................................................................................ 386 12.50 Effect of Granulated Slag on the Accelerated C 1293 Expansions of Aggregate E2-IA ................................................................................................. 386 12.51 Comparison Between the 26-Week Expansions Generated Using Accelerated C 1293 Procedures and the Different Granulated Slag Replacement .................... 387 12.52 Effect of Calcined Clay on the Accelerated C 1293 Expansions of Aggregate A4-ID ................................................................................................. 390 12.53 Effect of Calcined Clay on the Accelerated C 1293 Expansions of Aggregate A2-WY .............................................................................................. 390 12.54 Effect of Calcined Clay on the Accelerated C 1293 Expansions of Aggregate C2-SD ................................................................................................ 391 12.55 Effect of Calcined Clay on the Accelerated C 1293 Expansions of Aggregate E2-IA ................................................................................................. 391 12.56 Comparison Between the 26-Week Expansions Generated Using Accelerated C 1293 Procedures and the Different Calcined Clay Replacement ....................... 392 12.57 Effect of Lithium Nitarte on the Accelerated C 1293 Expansions of Aggregate A4-ID ................................................................................................. 395 12.58 Effect of Lithium Nitarte on the Accelerated C 1293 Expansions of Aggregate A2-WY .............................................................................................. 395 12.59 Effect of Lithium Nitarte on the Accelerated C 1293 Expansions of Aggregate C2-SD ................................................................................................ 396 12.60 Effect of Lithium Nitarte on the Accelerated C 1293 Expansions of

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Aggregate E2-IA ................................................................................................. 396 12.61 Comparison Between the 26-Week Expansions Generated Using Accelerated C 1293 Procedures and the Different Lithium Nitarte Replacement ..................... 397 12.62 Effect of Air Entrainment on the Accelerated C 1293 Expansions of Aggregate A4-ID ................................................................................................. 400 12.63 Effect of Air Entrainment on the Accelerated C 1293 Expansions of Aggregate A2-WY .............................................................................................. 400 12.64 Effect of Air Entrainment on the Accelerated C 1293 Expansions of Aggregate C2-SD ................................................................................................ 401 12.65 Effect of Air Entrainment on the Accelerated C 1293 Expansions of Aggregate E2-IA ................................................................................................. 401 12.66 Comparison Between the 26-Week Expansions Generated Using Accelerated C 1293 Procedures and the Different Air Entrainment Replacement .................... 402 12.67 Effect of Different Cement Alkali Contents on the Accelerated C 1293 Expansions of Aggregate A6-NM ......................................................................... 405 12.68 Effect of Different Cement Alkali Contents on the Accelerated C 1293 Expansions of Aggregate A4-ID ........................................................................... 405 12.69 Effect of Different Cement Alkali Contents on the Accelerated C 1293 Expansions of Aggregate A2-WY ......................................................................... 406 12.70 Effect of Different Cement Alkali Contents on the Accelerated C 1293 Expansions of Aggregate C2-SD .......................................................................... 406 12.71 Comparison Between the 13-Week Accelerated C 1293 Expansions of Concrete Prisms Made with Different Na2Oequiv. Contents .................................... 407 12.72 Comparison Between the Different Mitigation Alternatives Used With Aggregate A4-ID and the Accelerated C 1293 ...................................................... 409 12.73 Comparison Between the Different Mitigation Alternatives Used With Aggregate A2-WY and the Accelerated C 1293 ................................................... 409 12.74 Comparison Between the Different Mitigation Alternatives Used With Aggregate C2-SD and the Accelerated C 1293 ..................................................... 410 12.75 Comparison Between the Different Mitigation Alternatives Used With Aggregate E2-IA and the Accelerated C 1293 ...................................................... 410 12.76 Effect of Silica Fume, Granulated Slag, and Calcined Clay on the Accelerated C 1293 Expansions Aggregate A6-NM Using 0.80% Na2Oequiv. Cement ............. 415 12.77 Effect of Class C Fly Ash and Class F Fly Ash on the Accelerated C 1293 Expansions of Aggregate A6-NM Using a 0.80% Na2Oequiv. Cement ................... 415 12.78 Effect of Lithium Nitrate and Air Entrainment on the Accelerated C 1293 Expansions of Aggregate A6-NM Using a 0.80% Na2Oequiv. Cement ................... 416 13.1 C 1260 Results vs. C 1293 Results ......................................................................... 422 13.2a Characterization of Aggregate Potential Alkali-Silica Reactivity .......................... 425 13.2b Summary Characterization of Aggregate Potential AS Reactivity ......................... 426 13.3a Different Replacement Levels of Class C Fly Ash, Class F Fly Ash, Silica Fume, Slag, and Calcined Clay, Evaluated Using ASTM C 1260 and the Accelerated C 1293 Procedures (600C) ................................................................. 431 13.3b Trend line Illustrating the Relation Between ASTM C 1260 and Accelerated C 1293 in Evaluating the Use of Class C Fly Ash, Class F Fly Ash, Silica

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Fume, Slag, and Calcined Clay ............................................................................. 432 13.4 Different Dosages of Air Entrainment and Lithium Nitrate, Evaluated Using ASTM C 1260 and the Accelerated C 1293 Procedures (600C) .............................. 432 13.5 Comparison of the 14-Day C 1260 Expansions for the Different Entrained Air Levels ................................................................................................ 434 13.6 Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Air Entrainment Contents of Table 12.15 ...................................... 434 13.7 Comparison Between the 13-Week Expansions Generated Using the Accelerated C 1293 Procedures and the Different Air Entrainment ......................... 435 14.1 Flow Chart I for Assessing Aggregate’s Potential Alkali-Silica Reactivity .............. 440 14.2 ASTM C 1260 Expansion Criteria Using Different NaOH Solution Molarities to Investigate Effectiveness of Cement Alkali Content ........................................... 446 14.3 Flow Chart II for Determining Effective Preventive Measures ................................. 447 15.1 Characterization of Aggregate Potential Alkali-Silica Reactivity ............................. 454

1

CHAPTER ONE

INTRODUCTION

1.1 GENERAL

Alkali-silica reaction (ASR) is one of the most recognized deleterious phenomena

in concrete. ASR is a chemical reaction between the reactive silica contained in the

aggregates and the alkalis (Na2O and K2O) within the cement paste. The result is an

alkali-silicate gel that absorbs water and increases in volume. If the gel is confined

by the cement paste, it builds up pressure as it grows causing internal stresses that

eventually could crack the concrete.

Identifying the susceptibility of an aggregate to alkali-silica reaction (ASR) before

using it in concrete is one of the most efficient practices for preventing damage.

Several tests have been developed to identify aggregates subject to ASR, but each

has its limitations. A three-year research study was initiated on January 1, 1998 at

the University of Texas at Austin for investigating ASR in portland cement concrete.

The study was approved by the ICAR advisory of directors on November of 1997.

The scope of the study is essentially two fold: 1) develop more accurate testing

protocols for identifying aggregates which are subject to ASR and 2) develop

mitigation methods for preventing ASR damage in concrete in case a reactive

aggregate had to be used.

1.2 BACKGROUND AND PROJECT JUSTIFICATION

1.2.1 ASR Survey

In an effort to determine the incidence of ASR in the United States of America

(USA), a survey was conducted to get input from Departments of Transportation

(DOTs) across the country. Figure 1.1 shows a summary of the survey.

ASR Occurrence

No ASR Reported

No ASR Problems Because of Low Alkali Cement

No Response

2

Figure 1.1: Results of The DOT Survey

3

The survey consisted of several questions that will be detailed in a later chapter. All

DOTs were contacted; 39 DOTs responded. It was concluded that 31 states (79.5%)

out of the 39 have at some point experienced damage due to ASR. Eight states

(20.5%) have never experienced damage due to ASR and this was attributed to either

the use of innocuous aggregates or the use of low alkali cements. The survey

highlighted the fact that ASR is a national concern.

1.2.2 Testing Procedures

Over the years, several ASTM tests have been developed for the purpose of

identifying reactive aggregates. The most popular tests include:

ASTM C 295: “Guide for Petrographic Examination of Aggregates for Concrete” is

used to determine the physical and mineralogical characteristics of aggregates. The

test is used to describe and classify the constituents of an aggregate, to determine the

relative amounts of the constituent in the aggregate, and to compare samples of

aggregates from new sources to samples of aggregates from other well established

sources. Petrographic examination also provides a means of identifying types of

potentially deleterious minerals present in aggregates. The test method allows the

identification of most types of reactive silica minerals. However, a petrographic

examination will not result in a clear identification of materials such as

microcrystalline, strained, or microfractured quartz which can be found in a wide

variety of aggregates. These materials are usually present in aggregates that are

slowly reactive.

ASTM C 227: “Test Method for Potential Alkali Reactivity of Cement-Aggregate

Combinations (Mortar-Bar Method)” has been the most widely used test method

since the 1950s. The test is used to determine the susceptibility of cement-aggregate

combinations to alkali-silica reaction by means of measuring the change in length of

4

mortar bars made using the proposed combinations of materials for a job.

Voluminous amounts of literature exist reporting on the inadequacy of this test

method. Some papers mentioned that the use of wicks in the storing container lead

to alkali leaching and misleading results. Other research projects have documented

that the C 227 test is not suitable for identifying slowly reactive aggregates. Other

researchers have complained that the processing of aggregates is not realistic and that

the resulting aggregates have different surface areas, which leads to different ASR

reactivity and does not represent the actual reactivity of an aggregate.

ASTM C1260: “Test method for Potential Reactivity of Aggregates (Mortar-Bar-

Test)” is used to detect within 16 days the potential of aggregates in mortar bars for

exhibiting alkali silica reaction. It does not investigate combinations of aggregates

with cementitious materials nor does it represent the environments to which

aggregates will be subjected in the field. The alkali content of the cement does not

affect the expansion in this test method because the specimens are stored in a 1N

NaOH solution. If mortar bars exhibit high expansion, it is recommended that more

information be gathered about the aggregate using ASTM C 295 to determine

whether the expansion is due to alkali-silica reaction. C 1260 is capable of detecting

slowly reactive aggregates. Several researchers have reported that the test is very

severe and might identify an aggregate as potentially reactive even if it has a very

good long-term service record. The test has considerable value in providing a rapid

means of detecting potentially ASR aggregates. Recently, aggregates have been

identified as innocuous using C 1260 but have reacted deleteriously in the field with

low alkali cements. There are also some aggregates that have been identified as

reactive using C 1260 but have had over 30 years of good service records. As a

result, it is recommended that aggregate expansion results from this test be combined

with the results of a service record investigation for the aggregate in question or a

long-term concrete testing program.

5

ASTM C 1293: “Test Method for Concrete Aggregates by Determination of Length

Change of Concrete Due to Alkali-Silica Reaction” is used to determine the alkali-

silica reactivity of coarse and fine aggregates, by monitoring the length change of

concrete prisms over a period of one year. It is used to predict the reactivity of an

aggregate in an alkaline environment (1.25% Na2O or 5.25 kg/m3) under laboratory

conditions that will differ from field conditions. As a result, the test does not

duplicate actual field performance. Results of this test should be used to decide

whether precautions should be taken to prevent alkali-silica reaction expansions

before the tested aggregate is used in construction. When expansions from this test

method indicate that the aggregate is reactive (one-year expansions greater than

0.04%) petrographic examination (ASTM C 856) is required to confirm that the

expansion is due to alkali-silica reaction. Supplemental testing could also be

performed to confirm the test results. Such tests include ASTM C 277, C 1260, C

295, and C 289.

Clearly, an ideal test method for predicting the alkali-silica reactivity of

aggregates does not exist. A comprehensive evaluation of test methods is needed for

aggregates having known alkali-silica reactivity ranging from innocuous to highly

reactive.

1.2.3 Mitigation Alternatives

Soon after ASR was first identified as the cause of several concrete failures, it was

found that the use of mineral admixtures as a replacement of a portion of the cement

in concrete could reduce the ASR effects on concrete. The most commonly used

admixtures are fly ash, silica fume, and slag. Several natural pozzolans such as

calcined clay have also been reported effective in mitigating the ASR effects. The

use of air entrainment and lithium admixtures in concrete has been proven to

6

potentially mitigate the effects of ASR. Effective mitigation methods need to be

available for use with aggregates that are prone to ASR. In order to reduce the cost

of construction, it is important that reactive aggregate sources be used as effectively

as possible.

1.3 PROJECT OBJECTIVES

The overall objective of the project was to closely examine the alkali-silica

reaction expansion potential in portland cement concrete containing different

aggregate sources in the United States (U.S.) and then to relate the results of the

laboratory testing performed on these aggregates to their reported field performance.

Another objective of the study was to investigate ASR mitigation or prevention

methods using aggregates with established ASR performance. Specific objectives

were as follows:

1. Improve the Testing Program for ASR Evaluation of Aggregates: This includes

investigating, modifying, or developing better interpretation techniques for

ASTM C227, ASTM C1260, and ASTM C1293. A combination of the improved

tests will be assembled to generate a recommended protocol for a better ASR

evaluation procedure for aggregates.

2. Improve Mitigation Methods: Using mortar bars and concrete prisms,

respectively ASTM C 1260 and C 1293, mitigation alternatives were

investigated. These alternatives included the use of fly ash, silica fume, ground-

granulated slag, calcined clay, lithium nitrate, air entrainment, low alkali content,

and low permeability.

3. Improve Field Performance Recording: A database containing physical,

chemical, mineralogical, ASR expansion test results, and field performance for

7

each aggregate was initiated. The database will help improve the correct use of

aggregates in order to prevent ASR damage in concrete.

4. Implement Latest Findings: Final outputs of the project were presented at a

demonstration seminar at industry-selected sites.

1.4 WORK PLAN

A technical project advisory panel (PAP) was established to monitor the progress

of the research, to ensure effective use of resources, to act as a liaison between

researchers and industry members, to secure test samples, and to facilitate the

transfer of technology and prompt implementation. Twelve members representing

different sectors of the aggregate industry were chosen and added to the committee

after consultation. A list of the committee members is included in Appendix A. In

order to meet all the objectives of the project, six tasks were developed and

implemented. The list of tasks was as follows:

1. Task #1: Determine State-Of-Art: The purpose of determining the state-of-the-

art was to identify areas in which research will be needed to fill the existing gaps

in the available ASR technology. The state-of-the-art will be determined by:

Extensive literature search

Survey of Industry representatives such as National Aggregate Association

(NAA) and National Stone Association (NSA), and others.

Survey of knowledgeable professionals such as researchers, petrographers,

aggregate and concrete consultants

Survey of DOTs in the United States and other selected countries.

2. Task #2: Identify and Select Test Materials: Based on available information on

field performance, chemical composition, and mineralogical composition,

8

sources of aggregates representing the complete spectrum of ASR reactivity will

be selected for testing in the laboratory. In addition, the aggregates will represent

the various climatic regions and geographic areas of the U.S. Various types of

portland cement and admixtures will also be selected to result in a comprehensive

testing program.

3. Task #3: Laboratory Test Program for Evaluating and Modifying Test

Procedures: An extensive laboratory test program will be conducted to address

the different objectives of the study. ASTM test methods available to determine

the ASR reactivity of a specific aggregate include ASTM C227, C1260, C1293,

and C295. The objectives of the testing program are as follow:

Evaluate the efficiency and accuracy of currently available ASTM test

procedures and document their limitations, disadvantages, and potentially

misleading predictions.

Develop a correlation or document a lack of correlation between the results of the

different tests investigated.

Develop a correlation or a lack of correlation between the results of each

investigated test and the documented performance in service of the aggregates

being tested.

Develop modifications to available test procedures in order to improve their

efficiency, accuracy, and predictability of the performance of a given aggregate

when used in concrete.

Evaluate and develop mitigation methods capable of reducing or eliminating the

ASR-related damage of concrete when using a reactive aggregate source.

Mitigation alternatives include the use of fly ash, slag, silica fume, blended

cements, air entrainment, low permeability, and lithium nitrate.

9

4. Task #4: Document the Field Performance of Investigated Aggregates: In

order to define the relationship between the laboratory and field performance. An

effort will be dedicated to documenting the field performance of investigated

aggregates. Methods that will be used include contacting the aggregate

producers, DOTs, and other authorities that have used the aggregates.

5. Task #5: Establish Aggregate Database: A database will be initiated to correlate

the laboratory results performed on a specific aggregate source to its field

performance in concrete.

6. Task #6: Develop Recommended Guidelines: Upon completion of the work on

previous tasks, guidelines will be developed for:

Test protocols capable of accurately assessing the potential for ASR damage of

aggregate sources.

Mitigation methods for ASR reactive aggregates that will be used in concrete.

Procedures for establishing acceptance of an aggregate source on the basis of

laboratory evaluation or mitigating mix designs.

7. Task #7: Implementation: Recommendations from the research will be presented

to agencies that may have an interest in adopting all or a portion of the results.

8. Task #8: Reports: Reports will be generated as the research progresses. Reports

will be in the form of progress updates on quarterly basis, task completions, and

final reports.

1.5 BENEFITS

Accurate evaluation of the potential ASR of aggregates is essential for producing

durable concrete. In the industry today, there is a need for improved or modified

10

testing procedures capable of accurately predicting the susceptibility of aggregates

to ASR. These new procedures will permit the use of some aggregates that have

been, in the past, excluded on the basis of being classified as reactive. Effective

mitigation methods will permit the economic use of reactive aggregates that normally

would be excluded. In summary, the improved testing procedures and mitigation

methods will result in two major benefits to the industry and users: 1) aggregates

previously erroneously classified as reactive can be used and 2) many reactive

aggregates can be used by incorporating the appropriate mitigation methods.

Mitigation of ASR will extend the life of concrete structures and result in

substantial savings in repair and replacement costs. Based on estimates by the Bridge

Design Section in New Mexico, 20 bridges per year are built, 50 to 75 percent

replaced due to ASR-related distress. It is estimated that by reducing rehabilitation

and replacement of bridges, about $11 million to $15 million annual savings would

accrue (Mc Keen 1998).

Results of this study will increase the aggregate sources that can be used in

concrete, resulting in increased sales for producers and reduced costs for users. No

accurate estimates exist of the annual tonnage of aggregates that has been eliminated

because of alleged susceptibility of ASR, but if the results of this research would

enable even 25 percent of these materials to be used, the increased volume available

for use would increase substantially.

11

CHAPTER TWO

ALKALI-SILICA REACTION MECHANISMS

2.1 GENERAL DEFINITION

Alkali-silica reaction (ASR) is a reaction that takes place between the reactive

silica contained in aggregates and the alkalis in the cement paste. For the reaction to

take place in concrete, three conditions must exist: high pH, moisture, and reactive

silica. Various types of silica present in aggregates react with the hydroxyl ions

present in the pore solution in concrete. The silica, now in solution, reacts with the

sodium (Na+) and potassium (K+) alkalis to form a volumetrically unstable alkali-

silica gel. Once formed, the gel starts imbibing water and swelling to a greater

volume than that of the reacted materials. Water absorbed by the gel can be water

not used in the hydration reaction of the cement, free water from rain, snowmelt,

tides, rivers, or water condensed from air moisture (ACI 221, 1998). In general, the

reaction can be viewed as a two-step process (Farny 1996):

Step 1:

Silica + alkali alkali-silica gel (sodium silicate)

SiO2 + 2NaOH + H2O Na2SiO3.2H2O (2KOH can replace 2NaOH)

Step 2

Gel reaction product + water expansion

Since the gel is restrained by the surrounding mortar, an osmotic pressure is

generated by the swelling. Once that pressure is larger than the tensile strength of

the concrete, cracks occur leading to additional water migration or absorption and

additional gel swelling (ACI 221, 1998).

12

2.2 CONTRIBUTION OF THE SILICA TO THE REACTION

Various forms of silica or silicon oxide tetrahedron may be found in natural

aggregates. The silicon tetrahedron is shown in Figure 2.1 where Si4+ occupies the

center of the structure and four oxygen ions (O--), bonded to Si4+, occupy the corners

(Leming 1996). A crystalline silicate structure is formed by the repetition of the

silicon tetrahedron in an oriented three-dimensional space (Prezzi et al. 1997).

Quartz (SiO2) is an example of completely crystalline silica where the different

tetrahedra are linked by oxygen ions. Each oxygen ion is bonded to two silicons in

order to achieve electrical neutrality. Figure 2.2 shows the structure of quartz. A

complete tetrahedron cannot form on the surface of a crystalline structure. The

bonds between oxygen and silicon are broken on the surface resulting in negative

charges that are unsatisfied (Prezzi et al. 1997). Such structures are chemically and

mechanically stable, impermeable, and react only on the surface (Leming 1996).

Amorphous silicates (non-crystalline) are also formed by a combination of the silicon

tetrahedron with the exception that the tetrahedra are arranged in a random three-

dimensional network without forming a regular structure (Prezzi et al. 1997). As a

result, amorphous silica is more porous, has a large surface area, and as a

consequence, is very reactive. The more amorphous the silica is, the more reactive it

becomes. Certain volcanic aggregates, for example, contain glassy materials formed

by the rapid cooling of melted silica that prevents it from crystallizing and renders it

very reactive (Leming 1996).

Figure 2.1: Silicon tetrahedron (Silica)

Figure 2.2: Quartz structure (SiO2) (Crystalline Structure)

13

In addition to the degree of crystallization of silica, the amount of energy stored in

the crystal structure also affects the reactivity of an aggregate. Some silica structures

might contain large amounts of strain energy caused by heat and pressure usually

called strained structure. Aggregates containing this type of silica are likely to be

susceptible to deleterious alkali-silica reactions. However, the rate of reaction is

much slower than that of aggregates containing amorphous silica. Metamorphic

aggregates containing strained quartz are an example of such aggregates (Leming

1996).

Some aggregates contain crystalline silica formed by very fine crystals having

very large surface areas. These types of aggregates, such as chert, are prone to ASR

(Leming 1996).

The amount of silica contained in aggregates also affects their reactivity as shown

in Figure 2.3 (ACI 221, 1998). There is a maximum amount of silica beyond which

the reaction does not take place. This is called the pessimum effect. Aggregates

containing the following amounts of silica are susceptible to ASR (ACI 221, 1998):

Opal: more than 5%

Chert and chalcedony: more than 3%

Strained or microcrystalline quartz: more than 5%. Examples are: granites,

granite gneiss, graywakes, argillites, phyllites, siltstones, and natural sands and

gravels

Natural volcanic glasses.

14

2.3 ALKALI CONTRIBUTION TO THE REACTION

Depending on the type of reactive silica contained in aggregates, the alkali-silica

reaction can be divided into two groups (CSA 1994):

Group A: Alkali-silica reaction that occurs with amorphous (poorly crystalline)

silica minerals and volcanic or artificial glasses: Alkalis such as sodium (Na+) and

potassium (K+) present in the concrete paste will break the silica-oxygen bonds,

opening the crystal structure for alkalis and water. The result is a sodium silicate

hydrate (Na2SiO3.2H2O) that is very hygroscopic capable of imbibing large amounts

of water that in turn results in swelling pressures which, if larger than the concrete

Reactive aggregate content: Percent by mass of total aggregate

0 20 40 60 80

0 1 2 3 4 5 6

A B C D

A,D = Reaction but no cracking B = Reaction, cracking C = Reaction, cracking, excess of

reactive silica

Reactive silica content: Percent by mass of total aggregate

Exp

ansi

on

Figure 2.3: Effect of Silica Content on ASR (West 1996)

15

tensile strength, will cause cracking. Cracks will allow the penetration of additional

water causing the swelling pressures to increase. This type of reaction is fairly fast

and can cause cracking within a few years.

Group B: Alkali-silica reaction that occurs with various variety of quartz such as

strained and fractured quartz: Aggregates in this group either contain moderately

reactive silica or contain a small amount of silica. Since the reactive silica in these

aggregates is localized at the surface, the resulting gel product is more stable because

of the presence of large amounts of calcium hydroxide at the interface between the

aggregate and paste. Porous aggregates are an exception, because the alkalis will

penetrate the aggregates causing a less stable gel to form away from the interface and

the calcium hydroxide. This process will cause the softening of the aggregates.

Damaging effects of this reaction on concrete are a slower and less obvious process

than the effects of Group A.

The higher the concentration of potassium and sodium alkalis in concrete the

higher the concentration of the hydroxyl ions (higher pH) and in turn the more

readily the silica will react with the hydroxyl ions (ACI 221, 1998). If all the

ingredients for the reaction are present in fresh concrete then the gel can often be

detected at the interface between the aggregate and cement paste. Cracks will start

propagating from the aggregate particles. However, if the alkalis are provided from

an exterior source such as deicing salts, seawater, and industrial solutions then the

reaction will propagate from the exposed faces to the interior of the concrete (ACI

221, 1998).

16

CHAPTER THREE

REVIEW OF SELECTED NORTH AMERICAN RESEARCH

3.1 INTRODUCTION

This chapter includes a review of select research summarizing the latest

developments in the field of aggregate testing for potential ASR and ASR mitigation

methods.

3.2 TESTING FOR POTENTIAL REACTIVITY OF AGGREGATES

Information gathered on the past field performance of aggregates, might be the

most dependable method for predicting their alkali-silica reactivity in service.

However, field performance records may be inconclusive because (Bérubé and

Fournier 1993):

1. The aggregate being evaluated might have been used in a limited number of

structures that are old enough or that are exposed to sufficient moisture.

2. There is a lack of information on mixture properties used with the aggregate such

as the cement alkali content, curing methods, etc.

3. The exposure conditions might change from the reference structure to the

structure being built.

4. There might be a variation in the aggregate production from the period the

reference structure has been built to when the new construction begins.

As a result of the above arguments, aggregates are often evaluated in the

laboratory under more controlled conditions. In addition, it may be necessary to

rapidly evaluate reactivity of aggregates before the aggregates are used in a structure

which requires the need for test methods that are rapid, reliable, simple and

reproducible (Bérubé and Fournier 1993).

17

In order to be able to predict, in less than one year, how an aggregate will react in

the field after many years, at least one of the following conditions must be increased

in a testing method (Bérubé and Fournier 1993):

1. Alkali concentration: in the form of use of high-alkali cement or immersion in

alkaline solution.

2. Temperature: up to 380C, 800C, or autoclave.

3. Pressure: such as autoclave.

4. Humidity: either 100% RH or immersion in an aqueous solution.

5. Specific area: reducing the aggregates to powder or sand sizes

Bérubé and Fournier (1993) presented an extensive review of existing accelerated

testing procedures for predicting aggregate reactivity. The following is a summary of

some of the work and conclusions that they have referred to:

3.2.1 Petrographic Examination: ASTM C 295 (Bérubé and Fournier 1993)

Examining thin sections of aggregates using an optical microscope is helpful in

detecting potentially reactive minerals that could cause damage. These minerals

include opal, cristobalite, tridymite, volcanic glass, chert, chalcedony, and

microcrystalline quartz (Dolar-Mantuani 1983). In some cases, the petrographic

analysis can be completed using techniques such as X-ray diffraction, scanning

electron microscopy, or IR spectroscopy. Grattan-Bellew mentioned that

“petrographic examination alone cannot supply information on the expansiveness of

a particular cement-aggregate combination; however, experienced petrographers can

predict the likely behavior of aggregates with which they are familiar (Grattan-

Bellew 1989).” Information from petrographic analysis could aid in determining

which accelerated testing method should be used to further evaluate the alkali-silica

reactivity of an aggregate.

18

3.2.2 Chemical Method: ASTM C 289 (Bérubé and Fournier 1993)

This method consists of reducing the aggregate source to 150 to 300 µm particles

and then immersing it in a 1M NaOH solution at 800C for 24h. The solution is then

filtered and analyzed for the content of dissolved silica (Sc) and reduction in

alkalinity (Rc) both of which are plotted on a standard graph defining areas of

innocuous, deleterious, and potentially reactive aggregates.

Many aggregates are not adequately identified using this test. A significant

number of known alkali-silica reactive aggregates pass the test while many

innocuous aggregates are identified as deleterious. The poor performance of this

testing method can be blamed on 1) the interference of minerals such as calcium,

magnesium, silicates, gypson, zeolites, clay minerals, organic matter, or iron oxides

and 2) the crushing and preparation of the aggregates especially with aggregates

containing microcrystalline quartz.

3.2.3 Mortar Bar Method: ASTM C 227 (Bérubé and Fournier 1993)

This test has proved to be incapable of predicting the alkali-silica reactivity of

many slowly reactive aggregates, namely greywackes and argillites (Bérubé and

Fournier 1993). The presence of wicks inside the storage containers, which differ

from one laboratory to another, has been shown to largely affect the results obtained

from this method. It was found that the wicks promote the leaching of alkalis from

mortar bars causing lower expansions. As a result, a reactive aggregate ends up being

evaluated as an innocuous aggregate. It was also recommended that a reference

aggregate, which does not release significant amounts of alkalis, be included when

testing a new aggregate with unknown reactivity.

The alkali content of the cement used to make the mortar bars was also found to

largely affect the expansion results as shown in Figure 3.1. The cement alkali content

19

is not specified in the standard procedures of the test. A current practice that is being

used by many agencies is to increase the alkali content of the mortar bars to 1.25

percent Na2Oeq by adding NaOH to the mixing water.

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 2 4 6 8 10 12 14

Time, montths

AST

M C

227

Exp

ansi

ons,

%

0.66% Alkali Content1.03% Alkali Content1.25% Alkali Content

The water-cement ratio, which is not specified in the standard, was also found to

influence the expansion results as shown in Figure 3.2. Expansion increased with

decreasing water-cement ratio when the test was performed on typical reactive

aggregates from Quebec. This trend may be attributed to 1) a larger content of alkalis

caused by a lesser amount of pore solution or 2) a lower porosity, which leaves lesser

space for the reaction product to form (Bérubé and Fournier 1993). On the other

hand, Kishitani et al. tested several Japanese aggregates and found that the C 227

expansions increased as the water-cement ratio increased (Kishitani et al. 1986).

Figure 3.1: Effect of alkali content (Percent Na2Oeq) in the ASTM C 227 mortar bar method (Siliceous limestone from Ottawa, Ontario) (Bérubé and

Fournier 1993)

20

When opal was tested using C 227, the effect of the water-cement ratio was also not

clearly defined (Grattan-Bellew 1989).

0

0.02

0.04

0.06

0.08

0.1

0.12

0 2 4 6 8 10 12 14

Time, montths

AST

M C

227

Exp

ansi

ons,

%

W/C = 0.45W/C = 0.50W/C = 0.60

As a result of the survey, it was found that the storage condition, the water-cement

ratio, and the cement alkali content need to be controlled in order to produce more

reliable results. It was recommended to:

1. Use storage containers without wicks on the sides,

2. Increase the cement alkali content to 1.25% Na2Oeq,

3. Control the water-cement ratio to 0.50 by mass.

Figure 3.2: Effect of water-cement ratio in the ASTM C 227 mortar bar method (Siliceous Limestone from Trois-Rivieres, Quebec) (Bérubé and

Fournier 1993)

21

3.2.4 Accelerated Mortar Bar Method: ASTM C 1260 (Bérubé and Fournier

1993)

This test is being thoroughly investigated all over the world. In contrast to the

results of the C 227 test method, it was found that 14-day expansions decrease with

decreasing water-cement ratio. Since, in this test, mortar bars are immersed in a 1M

NaOH solution, the pore solution of the bars is controlled by the concentration of the

solution and the migration of the alkali ions in the bars is likely to decrease with

decreasing water-cement ratio.

It was also found that even though the test was capable of detecting numerous

aggregates, it was too severe for many aggregates that have performed well when

tested using the concrete prism method and that have performed well in the field. In

particular, these aggregates included greywackes, lithic gravels, some hornfelses,

gabbros, or andesites as shown in Figure 3.3.

Figure 3.3: Comparison Between ASTM C 1260 and ASTM C 1293 Results Illustrating the Severity of ASTM C 1260 (Bérubé and Fournier 1993)

22

Several researchers including Grattan-Bellew and DeMerchant and Soles have

suggested using different expansion limits with varying aggregate types namely

0.10% for reactive siliceous limestone, 0.20% for greywackes, and 0.15% for the

other types of aggregates. These researchers have also called for performing a

petrographic examination before performing any accelerated testing in order to

determine which limit to use (Gratta-Bellew 1990, DeMerchant and Soles 1992).

ASTM C 1260 should not be used for rejecting aggregates. Negative results

should highlight the need for additional investigation. This test was found to be “very

useful, as it was capable of recognizing most deleterious aggregates within 2 weeks

only”. The test should be considered as a screening tool for aggregates. The reaction

products formed within tested mortar bars were exactly the same as those in field

concrete affected by the alkali-silica reaction (Shayan 1989).

3.2.5 Autoclave Mortar Bar Methods (Bérubé and Fournier 1993)

The autoclave method that has been showing the most promising results consists

of forming mortar bars in accordance with ASTM C 227, but using a water-cement

ratio of 0.50 and an alkali content of 3.50 percent Na2Oequiv. The mortar bars are then

placed for 5 hours in an autoclave under 0.17 mPa (25 psi) at about 1300C.

When quarried silicate aggregates from Quebec were evaluated under the above

conditions, a proposed expansion limit of 0.10% expansion after 5 hours was found

to be acceptable, and the test was found to be more reliable than the accelerated

mortar bar test, ASTM C 1260. Limestones and dolostones have also been evaluated

using this test method. A proposed expansion limit of 0.15 percent after 5 hours

produced acceptable results that correlated to the field performance of aggregates.

Other aggregates were evaluated, and the results indicated that this autoclave method

23

is as reliable as C 1260. The only reactive aggregate that was not detected using the

autoclave was the same one that was not detected using the C 1260 procedures.

3.2.6 Concrete Prism Method CAN/CSA-A23.2-14A (ASTM C 1293) (Bérubé

and Fournier 1993)

This test is recommended for all types of aggregates, and a limit of 0.040 percent

expansion after one year seems to be acceptable for all reactivity levels.

The expansion of concrete prisms under the environments of the test are affected by:

1. Water-cement ratio: For reactive limestone aggregates, the expansion decreases

as the water-cement ratio increases. Similar results were obtained when

greywackes and argillite aggregates were tested. This behavior was similar to the

one observed with the C 227 test, and the same reasoning can be applied to the

concrete test. Opposite results were observed when opaline aggregates were

tested. Other research studies have shown that, by using 410 kg/m3 of cement to

make test prisms, the test was capable of predicting the potential reactive of

aggregates to correspond to field performance data (Grattan-Bellew 1990).

2. Cement fineness: the finer the cement, the more rapidly the alkalis in the cement

are diluted, and the higher the expansions (Krell 1986).

3. Storage conditions (Temperature and Humidity): The storage conditions have a

great deal of influence on the test results. Several research studies have

concluded that storing concrete prisms over water, in a sealed container with

wicks on the sides, at 100% R.H., and at 380C resulted in the most accurate

method for predicting potential reactivity of aggregates (Rogers and Hooton,

1989, Bérubé and Fournier 1993, and etc.)

24

3.2.7 Accelerated Concrete Prism Method (Used in Quebec) (Bérubé and

Fournier 1993)

This test method consists of storing the concrete prisms in 1M NaOH solution at

800C. It was found that a limit of 0.04% after 24 days was adequate for identifying

most of the reactive aggregates but was too severe for several numbers of innocuous

aggregates. It was concluded that this test should only be used as a screening method

but not for rejecting aggregates. Testing cores taken from field structures under the

conditions of this test is a very useful method for rapidly identifying the reactivity of

the aggregates in the core.

3.2.8 The Duggan Test (Bérubé and Fournier 1993)

Scott and Duggan proposed a testing procedure in which concrete prisms are cast

and submitted to accelerated curing. Small cores, 22-mm diameter by 50-mm length,

are taken from the prisms and subjected to cycles of immersion in distilled water at

210C. The cores are then heated in air at 820C after which the first reading is taken.

Subsequently the cores are stored in distilled water and periodic expansion readings

are taken. An expansion limit of 0.10% after 20 days of immersion is proposed as a

cut off point between reactive and innocuous aggregates (Scott and Duggan 1986).

The same researchers have proven in a later research that this test results in

erroneous aggregate characterization and is not adequate for alkali-silica reaction

(Scott and Duggan 1990).

3.2.9 Conclusions of the Survey by Fournier and Bérubé

Table 3.1 includes a list of all testing procedures mentioned by Bérubé and

Fournier (1993). Three tests were recommended: 1) the petrographic examination, 2)

ASTM C 1260 because it was the only rapid method that is statistically dependable,

and 3) ASTM C 1293, which is required if the tested aggregate failed the

25

petrographic examination and caused excessive expansions using C 1260. A

summary of these tests is presented in Table 3.2 (Nat 1998).

Table 3.1: Testing Methods for Potential Aggregate Reactivity (Bérubé 1993)

• Petrographic Method - ASTM C295 (≥ 1 day)

• Chemical Methods - ASTM C 289 chemical Method (2-3 days) - Modified Chemical Method (ASTM C 289 on insoluble residues) (2-3

days) - German Dissolution Test (1 day) - Osmotic Cell Test (< 40 days) - Gel Pat Test (≥1 week) - Chemical Shrinkage Method (1 days)

• Mortar Bar Methods - ASTM C 227 Method (6 months) -AFNOR P 18-585 Method (6 months) - CCA Method (6 months) - Danish Accelerated Method (5 months) - NBRI or ASTM C 1260 Accelerated Method (2 weeks) - Autoclave Methods (Chinese, Japanese, Canadian ) (≥ 3 days)

• Concrete Prism Methods - CAN/CSA A 23.2-14A or ASTM C 1293 (1 year) - AFNOR P 18-587 Method (8 months) - South African Method (21-24 days) - BSI 812 Method (1 year) - CCA Method (6 months) - Accelerated Method (used in Quebec) (1 month) - Autoclave Methods

26

Table 3.2: Most Widely Used Aggregate Tests for Identifying ASR Reactivity (Nat 1998)

Test

Method

Procedure

Type of Sample

Criteria

Significant Points

ASTM C 227 Potential Alkali-Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method)

Mortar bars are stored over water at high relative humidity and 38ºC (100ºF). Expansions are measured at 14 days, 1, 2, 3, 4, 6, 8, and 12 months and every 6 months after that if necessary

At least 2 mortar bars with standard dimensions 25x25x285 mm (1x1x11-1/4 in)

- 1- year expansion > 0.10% = Reactive - 1-year expansion < 0.10% = Innocuous - 3-month expansion > 0.05% = Reactive - if 3-month expansion < 0.05% wait for the 1-year expansion

1. Low cost 2. Slow test (6-month) 3. Fails to detect slowly reactive

aggregates (expansion is too small). 4. Wicks create excessive leaching of

alkalis out of mortar resulting in expansion reduction

5. There is a reduction of aggregate size (not realistic)

6. Aggregate surface is not the same as that of aggregate in field structures

7. All papers concerning C 227 stated that it is too mild

8. Fournier, Bérubé (1992) modified the test by increasing alkali content to 1.25% Na2Oequiv. and using plastic pails instead of wicks

ASTM C 289 Potential Alkali-Silica Reactivity of Aggregates (Chemical method)

Crushed aggregates are reacted with alkaline solution at 80ºC (176ºF) during 24 hours. Amount of dissolved silica and reduction in alkalinity are measured

Three of 25-gr samples of crushed and sieved aggregate

Plot Sc and Rc on a graph and locate the aggregates in predetermined potentially deleterious or innocuous areas

1. Quick 2. Good for rapidly reactive aggregates 3. Fail for slowly reactive aggregates

such as gneiss, schist quartzite. 4. Complicated 5. Costs more than C 1293 and C 1260 6. Considerable amount of carbonate in

silicate aggregates could alter the results and underestimate Sc value

ASTM C 1260 Potential Alkali Reactivity of Aggregates (Accelerated mortar bar method)

Mortar bars are immersed in 1N NaOH solution at 80ºC (176ºF) and expansions are measured at 4, 7, 11, and 14 days

At least 3 mortar bars with standard dimensions 25x25x285 mm (1x1x11-1/4 in)

- 14-day expansion <0.10% = Innocuous - 0.10% <14-day expansion < 0.20% = inconclusive - 14-day expansion > 0.20% = Reactive

1. Too severe, aggregates with good field performance may test reactive

2. Can detect slowly reactive aggregates 3. Fails to detect reactive granites,

gneisses which have microcrystalline quartz associated with strained quartz

4. Increase in alkali content of cement causes only small change

5. Reliable to evaluate the effectiveness of cementitious materials

6. If expansion > 0.10%, concrete prism test should be perform to confirm

ASTM C 1293 Test Method for Concrete Aggregates by Determination of Length Change of Concrete Due to ASR

Concrete prisms are stored over water at 38ºC (100.4ºF). Expansions are measured at 7, 28, 56 days, and 3, 6, 9, 12 months and every 6 months after than if necessary

3 prisms per cement-aggregate combination with standard dimensions: 75x75x285 mm (3x3x11-1/4 in)

Expansion of 0.04% or more at one year indicates potentially deleteriously reactive

1. More realistic 2. Low cost 3. Slow test (1 year) 4. Is very much dependable on storage

conditions 5. The use of damp tissue to wrap each

prism placed in sealed plastic bags gave good results

6. Testing in 1M NaOH at 80ºC gave the most rapid expansion but is unreliable.

7. Testing in 1M NaCl caused a combination of at least two expansion mechanisms

8. Testing in 1M NaOH at 38ºC is recommended

ASTM C 295 Petrographic Examination of Aggregates for Concrete

Visual examination and analysis of the sample by microscopy or other methods such as X-ray diffraction, differential thermal analysis or electron microscopy

Core sample, thin sections, or pieces of aggregates

Appearance of dark rim at the surface of aggregate. Certain amount of reactive constituents

1. Reliability depends on the experience of petrographers

2. Analysis of aggregates before casting is useful

3. Performing additional tests is recommended

27

3.3 ASR MITIGATION MEASURES

Mitigating or preventing deleterious expansions caused by the alkali-silica

reaction can be achieved by:

1. Limiting moisture: The alkali-silica reaction will not take place in a concrete

structure if the internal relative humidity of the concrete is lower than 80%. As a

result, keeping the concrete dry will prevent the reaction from occurring.

However, this is practically impossible for exterior structures. Lowering the

permeability of concrete by reducing the water-cement ratio reduces the internal

moisture and delays the reaction. However, a low water-cement ratio results in a

higher cement content, higher alkali content, and a reduced pore space which

could lead to higher expansions (ACI 221, 1998). Lowering the permeability of

concrete using mineral admixtures is a more viable approach to reducing the

deleterious effects of ASR (ACI 221, 1998). Applying a protective coating to

concrete is a good solution provided that the coating is correctly installed.

Because of the high cost of concrete coatings, this method has been used on a

limited basis.

2. Selecting Non-Reactive Aggregates: Using a non-reactive aggregate in concrete

and avoiding reactive aggregates will prevent ASR damage. This demands an

accurate testing protocol capable of correctly predicting the ASR reactivity of

aggregates. Such tests exist but need more refining and improvements (ACI 221,

1998). This is not economical in some regions where all locally available

aggregates are considered reactive.

3. Minimizing Alkalis: The most commonly used mitigation method is to control

the alkali content in the concrete for the purpose of reducing the hydroxyl ion

concentration and eventually the pH of the concrete. Cement is the major source

of alkali in the concrete. Alkalis are also provided, in smaller amounts, from fly

ash, mixing water, chemical admixtures, aggregates, and external sources such as

deicing salts and seawater. Controlling the alkali content of the cement has been

28

proven to decrease the expansions caused by ASR. A proposed limit of 0.60%

has been recommended for the alkali content of cement to be used in concrete to

reduce ASR expansions (ACI 221, 1998).

4. Mineral Admixtures: Ever since the alkali-silica reaction was discovered,

researchers have reported on the effectiveness of mineral admixtures in reducing

its deleterious effects on concrete. Effective mineral admixtures include fly ash,

silica fume, ground granulated slag, and calcined clay. In addition, there exist

documents reporting structures over 25 years old, containing reactive aggregates

and 20 to 30 percent fly ash. Mineral admixtures reduce ASR expansions by one

or more of the following mechanisms:

Reducing the alkali content of the concrete mix.

Reducing the pH of the concrete pore solution.

Consuming the calcium hydroxide, which might result in lower swelling.

Reducing concrete permeability.

Testing for the effectiveness of mineral admixtures is a challenge. Researchers

have reported that ASTM C 441, Effectiveness of Fly Ash and Mineral Admixtures

in Reducing Deleterious ASR Expansions”, is not a valid test for investigating the

effectiveness of mineral admixtures (ACI 221, 1998). ASTM C 1260 has been

successfully used for this purpose. If ASTM C 1293 is to be used, a two-year

period is recommended for obtaining the final expansion results (ACI 221, 1998).

5. Chemical Admixtures: Lithium salts have been used to prevent excessive ASR

expansions. Several salts have been tried, some of which have shown to be

effective. The best results were obtained using lithium nitrate (LiNO3) because

1) it is non-toxic and 2) minimal amounts were found to significantly reduce the

ASR expansions (ACI 221, 1998).

6. Air Entrainment: It was reported that adding 4% of entrained air to concrete

reduced the ASR expansions by 40%. It was also noticed that the expanding gel

29

had filled the air void system. However, this method has not yet been thoroughly

investigated nor has it been used in the field (ACI 221, 1998).

3.3.1 Minimizing Alkalis

The maximum limit of 0.60% Na2Oequivalent in cement was the result of a study

initiated in 1940 by Stanton of the California Division of Highways (Hill 1996).

During the same period of time the Bureau of Reclamation imposed the same limit

on their “important” projects, basing their decision on the work conducted by Blanks

and Meissner in 1945. Although the Bureau of Reclamation concluded that a 0.50%

Na2O is a much safer limit, a 0.60% limit was considered adequately safe and more

economical. Several other research studies performed between 1941 and 1963,

namely by Tremper (1941 and 1944), Kammer and Carlson (1941), Woolf (1952),

Bryant Mather (1952), and Oleson (1963), all concluded that cement with alkali

contents lower than 0.60% have shown very little to no ASR damaging effects (Hill

1996).

Over the years, the 0.60% Na2Oequivalent limit in the cement has been proven to be

very effective in preventing concrete damage due to ASR. There are, however, some

instances where cements with Na2Oequivalent of less than 0.60% and even less than

0.40% have resulted in deleterious expansions due to ASR (Hill 1996). In 1978,

Starks discovered concrete pavements in southeastern Wyoming and pavement

sidewalks in the Albuquerque, New Mexico area that had been deteriorated, in less

than 12 years, due to excessive ASR expansions. The alkali content of the cements

used for these projects was just under the 0.60% Na2Oequivalent limit. He also noticed

that some older structures in these areas constructed using cements with alkali

contents of about 0.48% have shown no ASR damage while some of them have

shown some map cracking. This fact was also noted by the first ASR researchers of

30

the 1940s who noticed that some aggregates might cause deleterious effects even

with very low alkali content cements (Hill 1996).

While the emphasis in the United States was concentrated on limiting the alkali

content of the cement, some of the western European countries as well as Canada

were trying to limit the alkali content of the concrete including alkalis from the

cement, aggregates, mineral, and chemical admixtures (Hill 1996).

Since there is a large diversity in natural aggregates, there is no magic number

that can be specified for the alkali limit of cement in order to prevent alkali-silica

reaction in concrete. A combination of measures might have to be employed to

prevent the reaction and that includes the use of low alkali cement in combination

with a mineral admixture (Hill 1996).

3.3.2 Effectiveness of Supplementary Cementing Materials

The effectiveness of supplementary cementing materials (SCM) in suppressing

ASR in concrete has been a subject for extensive research for a long time. Various

researchers and authors have reported opposing results on their effectiveness mainly

because of the wide range of available fly ash types and the different properties and

reactivity of aggregates being investigated (Shayan et al. 1996).

To minimize the risk of damage due to alkali-aggregate reaction in concrete

containing reactive aggregates, current UK guidelines permit the use of fly ash.

However, definite advice on the use of fly ash in concrete and on percentages to use

is not included in the guidelines because there exists conflicting evidence regarding

the alkali content of the fly ash and whether these are available for reacting with the

aggregate causing additional ASR damage (Thomas, Blackwell, and Nixon 1996).

This is especially a concern when the total alkali content of the concrete is being

31

controlled below a certain level in order to prevent ASR damage. Several

recommendations exist on how to deal with the alkali content of fly ash including

(Thomas, Blackwell, and Nixon 1996):

1. The Concrete Society (UK) recommends using the water-soluble alkali content of

the fly ash for determining the total alkali content of the concrete, and

2. The Building Research Establishment (UK), Department of Transport (UK),

French Guidelines, and Ireland guidelines recommend using one-sixth of the total

alkali content of the fly ash to calculate the total alkali content of the concrete.

This is a more conservative approach since 0.40% to 0.70% Na2Oequiv. is

equivalent to 0.10% water-soluble alkali content.

Evidence from the literature show that the use of sufficient levels of Class F fly

ash is effective in preventing ASR expansions in concretes containing natural

reactive aggregates even when the alkalis from sources other than the fly ash are

enough to cause deleterious expansions in concretes without any fly ash (Thomas et

al. 1996). In this case, the fly ash is considered to have a positive effect and to have

no reactive alkali contribution. However, when moderate levels of fly ash are used

in concrete containing very rapidly reactive aggregates with low alkali content

cements, then the fly ash will likely contribute alkalis to the reaction. In this case,

higher replacement levels may be required in order for the fly ash to completely

prevent the reaction from causing damage (Thomas, Blackwell, and Nixon 1996).

In order to clarify these matters, Thomas, Blackwell, and Nixon (1996) reported

about a study where five reactive aggregate sources from the UK area were

investigated. Aggregates were used to make concrete specimens using one high-

alkali portland cement (1.15% Na2Oequiv.) and three Class F fly ashes with varying

total alkali content (2.98, 3.46, and 3.86% Na2Oequiv.). Fly ash was used at different

replacement levels and concrete prisms were stored in plastic containers at 200C and

32

100% relative humidity. At 7 days, initial length measurements of all prisms were

taken before wrapping them in moist toweling and polyethylene. Some of the

wrapped prisms were stored at 200C while some were stored at 380C all at 100%

humidity. For the particular materials used in this study (UK reactive aggregates and

UK Cement and Class F fly ash) it was determined that (Thomas, Blackwell, and

Nixon 1996):

1. The effective alkali contribution of the ash depends upon the nature of the

reactive aggregate and the levels at which the weight of cement is replaced with

the fly ash (Figures 3.4 and 3.5).

2. The alkali content of concrete in the control specimens (neglecting the alkalis in

the fly ash) was enough to cause deleterious expansions and cracking of

specimens containing moderately reactive flint. Replacing the cement with 25%

fly ash was effective in reducing expansions. As a result, it was noted that the fly

ash has a positive effect in reducing damage due to AAR and does more then just

dilute the alkalis in the cement. Using the same reactive aggregate but replacing

6% of the cement with fly ash resulted in an increase in expansions for a given

cement alkali content. It was determined that 40% of the total alkalis in the fly

ash contributed to the expansions of concrete specimens. These matters are

illustrated in Figures 3.6 and 3.7.

3. Replacing 25% of the cement weight with fly ash was not effective in preventing

excessive expansions and cracking of specimens containing rapidly reactive

aggregates (i.e. aggregates that cause deleterious expansions with low alkali

content cement). These aggregates required using 35% fly ash by weight. The

contribution of the total alkalis in the fly ash to the expansions was estimated to

be 10%. This is illustrated in Figure 3.8.

4. It is inappropriate to use a singular value (e.g. one-sixth of the total alkali content

in ash) to estimate the contribution of the alkalis of the fly ash to the rate of ASR.

33

It is dependent upon the aggregate nature and levels of replacements. In addition,

using this approach ignores mechanisms, other than the alkali availability, that

contributes to the efficiency of the fly ash in reducing ASR damage.

0

20

40

60

80

100

2 3 4 5 6

Threshold alkali content for expansion in OPC concrete: kg/m3 Na2Oequiv.

Eff

ectiv

e al

kali

cont

ribu

tion

from

fly

ash:

%to

tal a

lkal

i Cristobalite

Greywacke

Siltstone/Siliceous limestone

Thames Valley Sand

6% fly ash

25% fly ash35-40% fly ash

Figure 3.4: Effect of Aggregate Reactivity and Percent Fly Ash Replacement on the Effective Alkali Contribution from Fly Ash

(Thomas, Blackwell, and Nixon 1996) OPC = Portland Cement Concrete with No Additives

34

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50

Replacement Level: %

Eff

ectiv

e al

kali

cont

ribu

tion

from

fly

ash:

% to

taal

kali

CristobaliteSiltstone/ Siliceous Limestone

Thames Valley Sand

Moderately Reactive Highly Reactive

Figure 3.5: Effect of Aggregate Reactivity on the Effective Alkali Contribution from Fly Ash (Thomas, Blackwell, and Nixon 1996)

35

0

0.1

0.2

0.3

0.4

3 4 5 6 7

OPC alkali content: kg/m^3 Na2Oequiv.

Exp

ansi

on a

t 4 y

ears

: %

Control - (no fly ash)25% F125% F225% F3

0

0.1

0.2

0.3

0.4

3 4 5 6 7

OPC alkali content: kg/m^3 Na2Oequiv.

Exp

ansi

on a

t 3 to

4 y

ears

: %

Control - (no fly ash)

6% F1

Figure 3.6: Using 25% Class F Fly Ash to Prevent Cracking of Concrete Made with a Moderately Reactive Aggregate (flint) (Thomas, et al. 1996)

OPC = Portland Cement Concrete with No Additives

Figure 3.7: Effect of Using 6% Class F Fly Ash with a Moderately Reactive Aggregate (flint) (Thomas, Blackwell, and Nixon 1996) OPC = Portland Cement Concrete with No Additives

36

0

0.1

0.2

0.3

0.4

0 2 4 6 8

OPC alkali content: kg/m^3 Na2Oequiv.

Exp

ansi

on: %

Control - 3 years25% F3 - 4 years35% F3 - 4 years

Specifications for using fly ash as an ASR mitigation alternative should take into

consideration that highly reactive aggregates require higher amounts of fly ash in the

mixture. As the calcium content of the fly ash increases (Class C fly ash), the

amounts of the fly ash used in the concrete should also be increased.

Pepper and Mather (1952) found that any deleterious expansion caused by ASR

can be eliminated by the use of a range of fly ash and other mineral admixtures.

Nixon and Gaze (1983), Nixon et al. (1986), and Stark (1978) investigated the

effectiveness of fly ash with slowly reactive aggregates and concluded that when 20

or 30% of the weight of cement was replaced with Class F fly ash, deleterious ASR

expansions were eliminated.

Figure 3.8: Effect of Class F Fly Ash on Cracking of Concrete Made with a Highly Reactive Aggregate (Thomas, Blackwell, and Nixon 1996)

OPC = Portland Cement Concrete with No Additives

37

Factors that influence the effectiveness of fly ash in mitigating ASR include the

composition of the cement and fly ash, levels of replacement and the fineness of

admixture. Dunstan (1981) found that while 25% fly ash addition was effective in

reducing ASR expansion, 5 to10% addition resulted in increasing the expansions

depending on the alkali content of the cement. Thomas et al. (1991) found that when

high alkali fly ash was used to replace 20% or more of the weight of cement in

concrete specimens containing a very reactive aggregate, ASR was greatly reduced

and very little evidence of the reaction was recorded. Blackwell et al. (1992) showed

that a Class F fly ash with 4.0% Na2Oequivalent was effective in preventing excessive

ASR expansions in concrete specimens made with a reactive greywacke and a high

alkali content concrete (7.0 kg Na2Oequivalent/m3). A 30-year testing program was

presented by Thomas et al. in 1992 which provided long-term evidence on the

effectiveness of 20% to 30% of a high alkali Class F fly ash in preventing ASR

cracking in a dam structure containing a reactive greywacke. Portions of the dam

that were constructed without the use of fly ash showed extensive ASR cracking.

To determine the effectiveness of fly ash, Hobbs (1994) conducted a study using a

very reactive synthetic cristobalite aggregate. He concluded that ASR expansion

depended upon 1) the alkali content of the cement (0.60-1.20% Na2Oequiv.), 2) the

alkali content of the fly ash (3.0-3.9% Na2Oequiv.), and 3) the level of replacement. He

found that the alkali contribution from Class F fly ash depended upon the level of

replacement as indicated in Table 3.3. The effect of Class F fly ash is illustrated in

Figure 3.9.

38

Table 3.3: Alkali Contribution from Fly Ash: Concrete with Cristobalite (Highly Reactive) (Hobbs, 1994)

Cement Alkali:% Na2Oequiv.

Alkali Contribution from fly ash: % Total alkali content

6% Ash Class F

25% Ash Class F

40% Ash Class F

0.6 100 16 9 0.9 100 11 3 1.2 60 0 0

Figure 3.9: Effect of Class F Fly Ash on Expansions of Concrete Containing a Highly Reactive Aggregate (Cristobalite) (Hobbs 1994)

OPC = Portland Cement Concrete with No Fly Ash

39

The calcium content of fly ash (Class C fly ash) also plays a role in its

effectiveness in suppressing ASR. Lee (1989) suggested that ASR expansions are

dependent upon the specific Na2O/SiO2 ratio of the fly ash. Nagataki et al., 1991,

investigated eight different fly ashes using high alkali cement and pyrex glass as a

reactive aggregate. They concluded that the ASR expansions were related to the

amount of soluble alkali and amorphous SiO2 content of the fly ashes as well as their

fineness. The reaction can be controlled by using finer SiO2, ashes with higher

amount of amorphous SiO2, and higher replacement levels. This is illustrated in

Table 3.4 and Figures 3.10 through 3.12 where it can be seen that fly ash F was the

most effective and had the finest SiO2 and the highest amount of amorphous SiO2.

They also concluded that the total alkali content of the fly ashes did not have any

effect in controlling ASR expansions.

Table 3.4: Chemical Compositions of three Investigated Ashes (Nagataki et al. 1991)

Fly Ash A Fly Ash B Fly Ash F L.O.I 3.12 2.54 5.09 SiO2 55.7 66.0 61.1 Al2O3 25.1 24.2 20.4 Fe2O3 6.14 3.15 5.72 CaO 2.55 1.44 1.99 MgO 2.19 0.38 1.48 SO3 0.76 0.06 0.78 TiO2 13.2 1.37 0.96 Na2O 1.54 0.32 0.66 K2O 1.21 0.28 1.53

Na2Oequiv. 2.34 0.50 1.67 Amorphous

SiO2 49.8 40.0 51.3

Mean Diameter 23.0 28.5 13.1

40

Fly Ash A

0

1000

2000

3000

4000

5000

6000

7000

0 10 20 30

Replacement Ratio of Fly Ash (%)

Exp

ansi

on 84 day56 day28 day14 day7 day3 day

Fly Ash B

0100020003000400050006000700080009000

0 10 20 30

Replacement Ratio of Fly Ash (%)

Exp

ansi

on 84 day56 day28 day14 day7 day3 day

Figure 3.10: Effect of Replacement Levels of Fly Ash A on ASR Expansions (Nagataki et al., 1991)

Figure 3.11: Effect of Replacement Levels of Fly Ash B on ASR Expansions (Nagataki et al., 1991)

41

Fly Ash C

0

1000

2000

3000

4000

5000

6000

7000

0 10 20 30

Replacement Ratio of Fly Ash (%)

Exp

ansi

on 84 day56 day28 day14 day7 day3 day

Thomas (1996) investigated three concrete structures containing alkali-silica

reactive aggregates and Class F fly ash. Two dams were constructed using reactive

greywacke aggregates and Class F fly ash replacing 20 to 30 percent of the weight of

cement and one dam was constructed using similar reactive aggregates but without

fly ash. The investigation indicated that the structures containing fly ash were in

great condition even after 25 years in service while the structure with no fly ash

exhibited ASR damage. In addition, the dam structure with no fly ash had a concrete

pore solution with an alkali concentration below 3 kg/m3 while both concrete dams

with fly ash had alkali contents in excess of this value. Based on these findings it

was concluded that Class F fly ash could be successfully used to prevent ASR if it

was used at sufficient levels of cement replacement. “The findings from this study

cannot be extended to Class C fly ash (Thomas, 1996).”

Figure 3.12: Effect of Replacement Levels of Fly Ash F on ASR Expansions (Nagataki et al., 1991)

42

Investigations performed before the construction of the Tallowa Dam, Australia,

indicated that the local aggregate was deleterious with regard to alkali-aggregate

reaction (Shayan et al. 1993). As a result, a cement with an alkali content lower than

0.60% in addition to fly ash were incorporated in the concrete to prevent the ASR

reaction damage from occurring. After more than 23 years of service life, the dam

has still not shown signs of ASR damage and is expected to continue the good

performance in the future. Aggregates separated from cores taken in 1995 were

determined to be alkali-silica reactive using ASTM C 1260. Even though the dam

contained potentially reactive aggregate, the combination of low alkali cement and

fly ash has proven to work in preventing damage due to ASR. Table 3.5 includes the

chemical properties of the cement and fly ash used in the structure and Figure 3.13

show the C 1260 results generated using cores from the dam. The concrete used for

the construction of the dam had the following proportions:

Maximum aggregate size 150 mm Cement Content 119 kg/m3 Fly Ash Content 59 kg/m3 Water/(cement + fly ash) ratio 0.50 Specified compressive strength (1 year) 13.8 MPa Actual mean cylinder strength (28 days) 15.8 MPa

(90 days) 21.8 MPa (1 year) 29.6 Mpa

Table 3.5: Tallowa Dam Cement and Fly Ash Properties (Shayan et al. 1993)

Oxide (%)

Portland Cement

Fly Ash SiO2 23.4 58.3 Al2O3 4.5 34.6 Fe2O3 5.0 CaO 63.4 1.5 MgO 0.6 1.1 Na2O 0.04 0.71 Soluble K2O 0.44 SO3 2.0 0.19

Na2O equivalent 0.33 --- Loss on Ignition 1.1 3.6

43

Hanks and Young (1992) found that 15, 22.5 and 30% cement replacement levels

with Class F fly ash were effective in reducing the 14-day expansions of mortar bars

made with two known reactive aggregates below 0.10% when tested in accordance

with ASTM C 1260. The 7.5% replacement level was not effective and showed 14-

day expansions greater than 0.20%. This is illustrated in Figure 3.14 for one of the

tested aggregates.

Figure 3.13: Expansion Curves for Concrete Cores Taken from Several Locations of the Dam and Stored in a 1M NaOH Solution at 400C

(Shayan et al., 1996)

44

Kakodkar et al. (1997) used the accelerated mortar bar test, ASTM C 1260, to

investigate the effectiveness of five Class C fly ashes in reducing ASR in mortar bars

incorporating five different sands, one highly reactive and four slowly reactive.

Mortar bars were cast using the different aggregates and replacing 10, 15, 20, 25, and

30% of the cement with the different Class C fly ashes shown in Table 3.6.

Conclusions were as follows:

1. The addition of Class C fly ashes at any level caused a decrease in the expansions

of mortar formed with highly reactive aggregates. When appropriate levels were

used, the expansion of mortar bars decreased below the test limit.

Figure 3.14: ASTM C 1260 Expansions vs. Replacement Levels of Cement with Class F Fly Ash (Hanks and Young, 1992)

45

2. When Class C fly ash is used with slowly reactive aggregates, there is a limit

replacement level (about 15 or 20 percent) below which the ash will cause an

increase in the 14-day expansions.

3. The oxide content of the fly ashes had an influence on ASR expansions. Low

oxide fly ashes (53.3 percent) were not effective in reducing the expansion of

mortar bars made using highly and slowly reactive aggregates. As the oxide

content increase the effectiveness of the fly ashes was slightly improved causing

a greater decrease in expansions.

4. The alkali content of the fly ashes did not seem to affect their effectiveness in

preventing expansions due to ASR in mortar bars containing highly and slowly

reactive aggregates.

5. Rresults are illustrated in Figures 3.15 and 3.16 which show the expansions of

one slowly reactive and one highly reactive aggregate.

Table 3.6: Composition of Class C Fly Ashes (Kakodkar et al., 1997) Fly Ash

#1 Fly Ash

#2 Fly Ash

#3 Fly Ash

#4 Fly Ash

#5 SiO2 36.5 32.8 29.9 35.1 46.7 Al2O3 20.8 20.0 17.7 20.3 13.4 Fe2O3 6.6 5.9 5.7 6.4 8.3

SiO2+ Al2O3+ Fe2O3 63.9 58.7 53.3 61.8 68.4 SO3 1.3 3.5 4.3 1.9 1.4 CaO 23.5 26.9 30.1 23.6 18.7 MgO 4.3 4.7 7.1 4.2 -- Na2O 1.12 0.77 1.70 1.92 --

Moisture Content 0.0 0.1 0.1 0.0 0.02 Loss on Ignition 0.1 0.4 0.2 0.2 0.02

46

00.050.1

0.150.2

0.250.3

0.350.4

0.45

0 10 15 20 25 30

Pecentage Fly Ash

14-D

ay E

xpan

sion

, %

Fly Ash #1Fly Ash #2Fly Ash #3Fly Ash #4

Innocuous

Slowly Reactive

Highly Reactive

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 10 15 20 25 30

Pecentage Fly Ash

14-D

ay E

xpan

sion

, % Fly Ash #1Fly Ash #2Fly Ash #3Fly Ash #4Fly Ash #5

Innocuous

Slowly Reactive

Highly Reactive

Figure 3.15: Comparison of 14-Day Expansions of Mortar Bars Made with the Different Fly Ashes and a Slowly Reactive Aggregate (Kakodkar et al. 1997)

Figure 3.16: Comparison of 14-Day Expansions of Mortar Bars Made with the Different Fly Ashes and a Highly Reactive Aggregate (Kakodkar et al. 1997)

47

Johnston et al. (1997) also used ASTM C 1260 to investigate the effectiveness of

Class F fly ash and ten natural pozzolans in preventing deleterious expansions caused

by the alkali silica reaction. A 14-day expansion lower than 0.10% was the criteria

for innocuous expansions. The results of the study are summarized as follows:

1. More than 25% of the cement had to be replaced with Class F fly ash in order to

effectively reduce ASR expansions of mortar bars made with a highly reactive

sand below 0.10% as seen in Figure 3.17.

0

0.05

0.1

0.15

0.2

0.25

0 10 15 20 25 30

Pecentage Fly Ash

14-D

ay E

xpan

sion

, %

Innocuous

Slowly Reactive

Highly Reactive

2. All investigated natural pozzolans were able to reduce ASR expansions for the

exception of one pozzolan, a white volcanic ash (VA2 in Table 3.7), which

actually increased the mortar bar expansions as seen in Figure 3.18.

3. Two natural pozzolans (LK2 and PS1E in Table 3.7), a gray highly siliceous fire-

clay and a dark brown to black non-calcareous shale, were the most effective in

controlling ASR expansions at levels of cement replacement between 15 and 25

Figure 3.17: Effect of Class F Fly Ash on the 14-Day Expansions of Mortar Bars Made with a Highly Reactive Aggregates and Tested Using ASTM C 1260

(Johnston et al., 1997)

48

percent by weight. Replacing the cement with 10% pozzolans was not effective

in preventing ASR excessive expansions above the test limit. Both pozzolans

were more effective than the investigated Class F fly ash in controlling ASR

expansions as seen in Figure 3.18.

Table 3.7: Composition of Selective Natural Pozzolans Tested by Johnston et al. (1997)

VA1 LK2 PS1E SiO2 -- 79.94 58.98 Al2O3 -- 7.58 16.59 Fe2O3 -- 1.11 6.29 CaO -- 0.25 1.57 MgO -- 0.15 2.11 Na2O 0.34 0.01 0.02 K2O 5.98 1.53 4.53 TiO2 -- 0.35 0.70 SO3 -- 0.13 1.01

MnO -- -- 0.05 BaO -- -- 0.05 NiO -- -- -- H2O -- 0.81 0.15

L.O.I. -- 4.37 1.10 Description White pure

ash Silicified volcanic

tuff Brown shale, expanded Pierre shale by

kiln heating

49

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 10 15 25

Pecentage Fly Ash

14-D

ay E

xpan

sion

, %

VA2PS1ELK2

Innocuous

Slowly Reactive

Highly Reactive

Alasali and Malhotra (1991) evaluated the effectiveness of high volume Class F

fly ash in preventing ASR damage caused by excessive expansions. Concrete

specimens were made using Class F fly ash with 58% of the weight of cement

replaced and a water-cementitious materials ratio of 0.31. NaOH was added to the

mixing water in order to increase the alkali content of the concrete. Concrete

specimens were stored under different curing conditions namely moist room at 230C

dry and wet cycles at 380C, in water at 380C, in 5% NaCl solution at 380C, in 1M

NaOH solution at 380C, in 1M KOH solution at 380C, in 5% NaCl solution at 800C,

in 1M NaOH solution at 800C, and in 1M KOH solution at 800C. Expansion

measurements were carried out for 275 days. It was concluded that expansions of

concrete prisms made with 58% Class F fly ash were insignificant regardless of the

test method used and of the addition of NaOH to the mixing water. Figure 3.19 is an

Figure 3.18: Effect of Selective Natural Pozzolans on the 14-Day Expansions of Mortar Bars Made with a Highly Reactive Aggregates and Tested Using ASTM

C 1260 (Johnston et al., 1997)

50

example of the expansions generated when concrete prisms were stored in a 1M

NaOH solution at 380C.

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 100 200 300

Age, Days

Exp

ansi

on, %

No Fly Ash

No Fly Ash + Alkali

Cement + Fly Ash

Cement + Fly Ash +Alkali

The Canada Center for Mineral and Energy Technology (CANMET), under

contract to Lafarge (Canada), investigated the effectiveness of 15 fly ashes, slags,

condensed silica fume, and natural pozzolans in reducing expansion of concrete and

mortar caused by alkali-aggregate reaction. Two reactive siliceous aggregates were

used in combination with the cementitious materials and high alkali content cement

and results were compared to expansion of specimens made with low alkali content

cement. Expansions were monitored over a five-year period. Properties of

investigated fly ashes are included in Table 3.8, and properties for investigated silica

fume, natural pozzolan, and slag are included in Table 3.9.

Figure 3.19: Expansions of Concrete Prisms Made Using a Cement with 1.13% alkalis, a Reactive Aggregate (Spratt), and 58% Class F Fly Ash. Prisms were Stored in a 1M NaOH Solution at 380C (Alasali et al. 1991)

51

Table 3.8: Properties of Investigated Fly Ashes (Chen et al. 1993)

Table 3.9: Properties of Investigated Silica Fume, Natural Pozzolan, and Slag (Chen et al. 1993)

52

It was concluded that (Chen et al. 1993):

1. The desirable characteristics of a cementitious material for reducing ASR

expansions due to AAR are:

a) low alkali content

b) high 45 µm fraction

c) high total acidic oxides (SiO2 + Al2O3 +Fe2O3).

2. ASTM C 441 and ASTM C 618 are not reliable in assessing the effectiveness of

cementitious materials in mitigating ASR.

3. From the materials listed in Tables 3.8 and 3.9, only several were effective in

decreasing expansions below testing limits. Findings for the effective materials

are summarized in Table 3.10. It should be noted that only Class F fly ashes were

effective in decreasing expansions below a safe limit and that none of the

investigated Class C ashes were effective in doing so.

Table 3.10: Effective Levels of Replacements for Materials Effective in Mitigating the ASR Damage (Chen et al. 1993)

Refer to Table 3.8 And Table 3.9

Pessimum %Replacement

Effective % Replacement

Critical alkali as solubleNa2O (kg/m3)

Lingan fly ash Class F

10 40 3.5

Dalhousie fly ash Class F

10 40 3.3

Sundance fly ash Class F

10 40 3.2

Lakeview fly ash Class F

10 40 3.4

Standard Slag 35 65 1.9 Atlantic Slag 35 65 1.9 SKW condensed silica fume

5 15 4.7

Amherst natural pozzolan

10 30 3.9

53

4. The effectiveness of the cementitious materials in reducing expansions was

coupled with a reduction of compressive strength of concrete. Fly ashes that were

effective in reducing ASR, especially at 50% cement replacement level, resulted

in lower compressive strengths. The reduction was greater in the 28-day strength

than the 84-day strength. Fly ashes that were not effective in reducing ASR

expansion either increased concrete strength or maintained the same strength of

the control concrete. Silica fume and natural pozzolans that were effective in

reducing ASR expansions resulted in a substantial increase in 28- and 84-day

strengths. When cement was replaced with 65% slag, the ASR expansions were

lower than testing limits, however, the concrete strength was decreased.

A study was conducted at King Fahd University of Petroleum and Minerals in

Dhahran, Saudi Arabia. Using ASTM C 441 and ASTM C 227 the following

conclusions were drawn (Rasheedbuzafar 1991):

1. Replacing cement with 10 to 20% silica fume or 60 to 70% slag reduced the C

227 6-months expansions below the limit of 0.10% as seen in Figure 3.20.

2. There is a strong indication that the mechanism by which the silica fume and slag

reduce ASR expansion is through lowering the hydroxide ion concentration in the

pore solution. However, there are also some deviations that indicate that other

mechanisms are taking place.

3. When used with low alkali cements, 60% of slag was found to be very effective

in removing alkalis from the pore solution and thus reducing ASR expansions.

When using comparable alkali contents of cements, 60% slag had similar effects

to 10% silica fume. As the alkali content of the cement increased, the

effectiveness of slag decreased.

4. Replacing cement with 10% silica fume was adequate in controlling ASR

expansions.

54

0.865

0.009

0.023

0.047

0.028

0 0.2 0.4 0.6 0.8 1

Plain Concrete

10% Silica Fume

20% Silica Fume

60% Slag

70% Slag

6-Month Expansion, %

In 1996, Thomas published a report in which he included a critical review of

published work up to May of 1994. The literature review concentrated on work

completed towards better understanding of the effects of fly ash and slag on ASR

expansions. More than 400 published references were examined and evaluated.

Particular attention was concentrated on work performed by the:

1. National Building Research Institute (NBRI) in the Republic of South Africa,

2. British Cement Association (BCA),

3. Building Research Establishment (BRE) in London,

4. CSIRO in Australia,

5. University of Texas at Austin, and

6. Concrete Society Technical Sub-Committee on AAR.

Figure 3.20: C 227 Expansion after 6 Months for Specimens Made with Different Replacement Levels (Rasheedbuzafar 1991)

55

Class F Fly ash, Class C fly ash, and slag concrete structures from around the

world were reviewed. Most of the structures with the exception of two showed

adequate performance because of the use of Class F fly ash, Class C fly ash, and slag

(Thomas 1996).

The following conclusions and recommendations were noted:

1. ASTM C 441 is not reliable for assessing the effectiveness of fly ash and slag in

mitigating ASR.

2. The satisfactory performance of Class F fly ash, Class C fly ash, and slag

concrete structures from around the world should confirm their ability to mitigate

damaging ASR. However, there are a few exceptions in which fly ash and slag

concrete performed poorly which emphasis that these materials do not guarantee

a cure.

On the Use of Fly Ash (Thomas 1996)

3. Low calcium fly ash (Class F) is not very effective with highly reactive

aggregates that are reactive with low alkali cements (less than 0.50%), such as

cristobalite and silstone. However, low-calcium fly ash is highly effective with

the less reactive aggregates such as greywacke, argillite, quartzite, etc.

4. Limiting the alkali content of the concrete will not enhance the effectiveness of

low-calcium fly ash (Class F). “The expansion in fly ash concrete appears to be

somewhat independent of the concrete alkali content in many cases.”

5. As the calcium content of the fly ash increases, its effectiveness decreases and

the proportion needed for effective mitigation increases for the same aggregate.

6. High-calcium fly ash (Class C), as well as slag, is very sensitive to the alkali

content of the concrete.

7. It is very critical to be able to classify the reactivity of an aggregate before

attempting to specify an adequate level of fly ash or slag replacement. However,

56

such an aggregate classification did not exist at the time the report was

conducted.

8. Table 3.11 includes an example of specifying fly ash for effective use. The levels

in the table are approximations.

Table 3.11: Example for Specifying Fly Ash with Reactive Aggregates (Thomas

1996)

CaO content of ash (%)

Minimum fly ash proportion (%) Max. Total alkali level

in ash (Na2Oequiv.)

Max. OPC Total alkali in

concrete kg/m3 Na2O

Aggregate Reactivity

Low

Medium

High

< 10 (Class F) 20 30 40 5.0 5.0

10 – 20 25 40 50 4.5 4.0 > 20

(Class C) 35 50 60 4.5 3.0

OPC = Original Portland Cement with No Additives

On the Use of Slag (Thomas 1996)

9. Slag is less effective with highly reactive aggregates that are reactive with low

alkali cements (less than 0.60%).

10. As the reactivity of aggregates decreases, the effectiveness of the slag increases

with increasing level of replacement (greater than 65% replacement). At this

stage, the contribution of the alkali content of the cement is less important.

11. The contribution of the alkali content of the cement becomes more significant at

lower levels of slag (less than 50% replacement).

12. When low levels of replacement are used with highly reactive aggregates, the

alkali content of the slag becomes very critical. The higher the alkali content of

the slag the less effective it is in reducing the ASR expansions below safe limits.

13. Slag is less effective than low-calcium fly ash (Class F). Slag is also more

influenced by its alkali content and the alkali content of the cement than low-

calcium fly ash.

57

14. An example of slag specification is included in Table 3.12.

Table 3.12: Slag Specification Example (Thomas 1996) Total Alkali Level in

blended cement (OPC + slag)

(% Na2Oequiv.)

Maximum Slag Proportion (%) Aggregate Reactivity Defined by ASTM C 1293

Low Medium High < 0.8 35 50 65

0.8 –1.5 50 60 70 > 1.5 60 70 75

Max. OPC alkali level in concrete (kg/m3 Na2Oe)

3.5 3.0 2.5

OPC = Portland Cement with No Additives

On Rapid Testing Procedures for Supplementary Cementitious Materials (SCM)

(Thomas 1996)

15. ASTM C 441 is unsatisfactory. There is a need for developing test methods that

will accurately determine the effect of SCM in a reasonable amount of time.

16. There is an increasing interest and success with the use of ASTM C 1260

procedures. However, this test method “requires a higher level of Class C fly ash,

Class F fly ash, and slag to control deleterious expansion compared to the

standard concrete test, ASTM C 1293.”

3.3.3 Control Mechanisms of Supplementary Cementitious Materials (SCM)

The various proposed mechanisms of control can be summarized as follows (Xu

et al. 1995):

1. The pozzolanic reaction between mineral admixtures and cement hydrates results

in a decrease in the permeability of the cement paste which in turn reduces the

mobility of ions in the concrete,

2. Mineral admixtures will result in higher strength that provides higher resistance

to the expansive stresses produced by ASR,

58

3. The alkalinity of the concrete pore solution is reduced by the use of mineral

admixtures,

4. Mineral admixtures deplete Ca(OH)2 in the cement paste,

5. The pozzolanic reaction produces a secondary hydrate that entraps alkali ions in

the cement.

The chemistry of pore solution of cement pastes incorporating different amounts

of two silica fumes, three pulverized fly ash, and one ground granulated blast furnace

slag was evaluated by Ducheness and Bérubé (1994) using the high pressure

extraction method. Examinations were performed after curing the cement pastes for

7, 28, 84, 182, 364, and 545 days at 380C and 100% relative humidity. Results of the

pore solution examinations were related and compared to expansions obtained over a

two-year period using the Concrete Prism Test, ASTM C 1293 or CAN/CSAA23.2-

14A. Concrete specimens were made with two very reactive aggregates using the

same water-cementitious materials ratio. An expansion lower than 0.04% after two

years was considered to be innocuous. It was concluded that the effectiveness of

silica fume, fly ash, and slag was attributed to their ability for decreasing the alkali

concentration in the pore solution down to a safe level. An alkali concentration of

0.65M, NaOH + KOH, over a long period of time was recommended. No significant

expansions occurred in specimens made with very reactive aggregates which had

pore solutions with alkali concentrations below 0.65N. This level was easier reached

when the alkali contents of the cementitious materials and the concrete were the

lowest and the cementitious materials content was the highest (Duchenesse and

Bérubé, 1994).

59

3.4 FINAL REAMARKS

After reviewing the selected research discussed earlier, it was clear that even

though there exist conflicting results about the effectiveness of some of the

mitigation alternatives, it is possible to mitigate ASR in concrete. The effectiveness

of an alternative depended upon the degree of reactivity of aggregates, the type of

alternative used, and the dosages used. It was also noticed that there is a lack of

specifications for the use of mitigation alternatives, which is mainly caused by the

large variety of aggregate reactivity and by the lack of accurate testing procedures

capable of predicting the degree of aggregates’ reactivity and determining the

effectiveness of a proposed alternative. It is possible however, to develop guidelines

and recommendations to be used for minimizing concrete damage due to ASR. These

guidelines and recommendations need to be formulized and proven.

60

CHAPTER FOUR

REVIEW OF INTERNATIONAL EXPERIENCE WITH ASR

4.1 INTRODUCTION

An international survey was conducted in order to determine the state-of-the-art of

alkali-silica reaction worldwide. The survey concentrated on two major areas:

1. testing methods used to predict aggregate reactivity, and

2. alternatives used for mitigating the reaction.

The following is a brief summary of the survey of practices worldwide for dealing

with alkali-silica reaction in concrete.

4.2 RILEM SURVEY (Nixon And Sims 1996)

A RILEM technical committee, RILEM TC-106 (Alkali-Aggregate Reaction),

was formed in 1988 to develop internationally approved methods for identifying the

alkali-reactivity of aggregates. The committee conducted a survey of participating

countries and was regularly updated. The following section presents the findings of

the survey.

Results from the survey, summarized in Table 4.1, indicated that there exists a

general interest in each of the petrographical, chemical, and expansion tests

categories, with the most emphasis and recognition being concentrated on the most

accelerated expansion tests methods such as ASTM C 1260. However, different

countries preferred different tests, and it was not possible to find a single test or a

series of tests that has been adopted by most countries. In addition, it was not

possible to find a “strong relationship between the reactive aggregates identified and

the methods preferred for aggregate testing and assessment (Nixon and Sims, 1996)”.

It was also found that there is an increased interest in developing test methods

capable of producing reliable results in a short period of time. Although ASTM C

61

1260 is gaining acceptance in a number of countries, several other test methods are

being developed and investigated.

It was not clear from the survey if the acceptance of a certain test method in a

country was based on the ability of a test method to predict the behavior of

aggregates in actual structures or service records. The general impression was that

test methods have been adopted from elsewhere and the interpretative criteria of the

test have been modified base on local experiences.

Table 4.1: Survey Results (published by RILEM in 1996)

Country

Petro-graphy ASTM C 295

Chemical ASTM C 289

Expansion

Mortar ASTM C 227

Expansion Concrete

ASTM C 1293

Expansion Ultra-

Accel’d ASTM C 1260

Other Australia Belgium Denmark France

Germany Hong Kong

Iceland Italy Japan

Netherlands N. Zealand

Norway Romania Russia

S. Africa UK

U.S.A. = Method sometimes used or being developed = Important method

All countries, with the exception of Germany, reported that no one test is capable

of providing a comprehensive assessment of aggregates for their alkali-aggregate

62

reactivity. Germany has required that all aggregates have a satisfactory performance

when tested with specified methods established for materials in a “closely defined

geographical region”. Finally, the survey indicated that there is no test method

universally accepted for assessing the susceptibility of aggregates to the AAR.

4.2.1 Specific RILEM Survey Conclusions Related to Testing Procedures

(Nixon and Sims, 1996)

1. Petrographical examination: Petrographic examination is universally considered

adequate for identifying potentially reactive constituents in the aggregates. Most

participating countries reported that petrographic examination is used to evaluate

aggregates for ASR, and over half of the countries classified the method as being

the best. The reported range of rock types susceptible to ASR was extremely

diverse. However, there seemed to be an agreement over the range of potentially

reactive constituents such as opal, microcrystalline quartz, etc, contained in the

aggregates.

2. Chemical testing methods: Most countries performed some type of chemical test.

There appeared to be a universal adoption of the ASTM C 289 test, often with

modified interpretation procedures. No country had reported that ASTM C 289

or similar test methods are the best methods to use. This lead to the impression

that results of ASTM C 289 were best used to support results from other test

methods. In France new test procedures have been standardized under “The

Kinetic Method” and the test is being evaluated internationally.

3. Expansion Methods: With the exception of Germany and Belgium, all countries

reported the use of a form of mortar or concrete expansion tests. Methods used

worldwide shared many similarities and potential differences mainly different

storage conditions. A universally agreed upon expansion testing method was not

apparent and a method using concrete specimens was more likely to be

acceptable universally than one using mortar bars.

63

4. Ultra-Accelerated Expansion Methods: Most replies indicated that the ultra-

accelerated expansion methods are more concerned with determining the

presence of potentially reactive constituents in the aggregates rather then being

concerned with the likelihood of expansion. Replies also indicted that this could

only be achieved with the long-term expansion methods. In addition, most replies

indicated that the long-term expansion tests are not suitable for specification

purposes. As result, there was a universal interest in the accelerated expansion

methods that are capable of producing adequate results in less than a month. A

universally acceptable ultra-accelerated method should also be developed. The

method should be able to predict the performance of the aggregates when tested

with the long-term concrete test. In particular, ASTM C 1260 was becoming

widely used. Denmark, the Netherlands, and Norway used a slightly different

version of ASTM C 1260, and France was investigating the Chinese microbar

test.

5. Other Test Methods: Several other testing procedures are being developed and

investigated however, none have gained international acceptance. At this stage,

efforts should be spent on improving the most established procedures.

6. Overall Survey Conclusion: The overall survey conclusion was that it seems

possible to reach an international agreement on a series of tests for assessing

aggregate reactivity. For example, using the following test procedures in a

sequential order: first a petrographic examination should be performed supported

sometimes by a chemical analysis. If a potentially reactive aggregate is identified

then the concrete prism expansion test should be performed. An ultra-accelerated

mortar-bar test might be used to provide an early prediction of the performance

of the concrete prisms.

64

4.3 ASR IN AUSTRALIA

4.3.1 Evaluating the Reactivity of Aggregates

Alkali-silica reaction has been the topic of many research studies in Australia. The

original test method used to predict Australian aggregate reactivity consisted of

combining appropriately graded fine aggregate with various cements to form mortar

bars measuring 25 x 25x 285 mm. The cement-to-aggregate ratio was 0.50 and

water-cement ratio was 0.40 to 0.50. Specimens were then stored at 100% R.H. in

sealed containers at a temperature of 150C. Length change was monitored

periodically every two years. This test was shown to be very slow and not practical

(Shayan, Green, and Collins 1996).

In addition, past experience showed that the quick chemical test, ASTM C 289

(AS 1141 section 39), and the long term mortar bar test, ASTM C 227 (AS 1141

section 38) were inadequate for predicting the ASR reactivity of most Australian

aggregates (Shayan, Green, and Collins 1996).

Following current trends, investigations, and recommendations, several

accelerated testing procedures were investigated at CSIRO, which included storing

concrete prisms and mortar bars in saturated NaCl solutions and in 1M NaOH at 50

and 800C. Results obtained using concrete prisms were unsatisfactory showing

erratic expansions. Results of the mortar bars in the 1M NaOH solutions were more

consistent and more reliable. When alkalis were added to the concrete prisms, more

consistent results were obtained, but a significant reduction in the concrete strength

was noticed (Shayan, Green, and Collins 1996).

Based on the field performance of several Australian aggregates in concrete

structures and the results of the accelerated mortar bar test (similar to ASTM C 1260)

performed on these aggregates, evaluation criteria were established as follows: 10-

65

day expansions of 0.10% or greater identifies reactive aggregates and 21-day

expansions of 0.10% or greater identifies slowly reactive aggregates. It was noted

that this accelerated mortar bar test was found to be more reliable than the autoclave

test. Through a series of research studies, Shayan showed that the accelerated mortar

bar (or ASTM C 1260) could be used to evaluate the effectiveness of fly ash and slag

in mitigating ASR expansions (Shayan 1990, 1992).

Another test that was investigated in Australia is a concrete prism test which

consist of steam curing the prisms and subsequently storing them at 500C and 100%

R.H. Limited data have been generated using these test conditions (Shayan, Green,

and Collins 1996).

Several aggregates with different field performances were tested using the

chemical method (ASTM C 289), the standard mortar bar (ASTM C 227), the

concrete prism (similar to ASTM C 1293), and the accelerated mortar bar (similar to

ASTM C 1260). The results are shown in Table 4.2 where it can be seen that the

concrete prism test and the accelerated mortar bar are the most reliable test methods

(Shayan, Green, and Collins 1996).

Describing the trend of aggregate testing for ASR in Australia, Shayan mentioned

that it is likely that “new test methods including the accelerated mortar bar test and

the concrete prism test (both normal and steam-cured) will be introduced. The

petrographic analysis, ASTM C 295 is likely to remain as a useful tool for the

identification of possible reactivity (Shayan 1996).”

66

Table 4.2: Classification of Aggregates by Different Test Methods (Shayan 1992)

Aggregate Service Record

Test Method

Chemical C 289

Standard mortar bara

C 227

Concrete prism

Similar to C 1293

Accelerated mortar barb

C 1260 1 --- NR NR PRc R 2 --- NR NR NR NRd 3 --- R NR NR Pessimum 4 --- Borderline NR R R 5 R R Re PRc R 6 R NR NR Rf R 7 R NR NR Rf R 8 R NR NR R R 9 --- NR NR NR NR

10 --- NR NR R R 11 --- Borderline NR R R 12 --- Borderline NR R R 13 --- NR NR R R 14 --- NR R R R 15 R R R R R

aCement alkali = 1.38% Na2Oe; bBased on criteria proposed by Shayan; cDepends on the level of alkali in concrete; dExcept for one batch;eExpansion exceeded 0.10% after one year, but not six month; fat high alkali content. R = Reactive; PR = Potentially Reactive; NR = Non-Reactive.

Shayan, Ivanusec, and Diggins (1994) investigated the reactivity of five sands

with different petrographic properties but mainly slowly reactive. The investigated

testing procedures included (Shayan, Ivanusec, and Diggins, 1994):

1. Mortar bar test at 400C and 100% R.H.: Mortar bars were made in accordance

with ASTM C 227 except that the sand was used as received without any

processing. NaOH was added to the mixing water in order to increase the alkali

content of the bars to 1.38 and 1.8% Na2Oeq. The W/C used was between 0.30

and 0.40. Mortar bars were cured in fog for one week while being covered with a

polythene sheet. Subsequent curing consisted of storing the bars at 400C and

100%.

67

2. Accelerated mortar bar test in NaOH solutions at 800C: Mortar bars were

made in accordance with ASTM C 227 and cured in fog at 230C for 3 days before

starting the accelerated procedures. Subsequently, one series of specimens was

stored in each of the 0.50, 0.75, and 1M NaOH solutions at 800C.

3. Accelerated mortar bar testing using autoclave at 1270C: Specimens, 25 mm x

25 mm x 285 mm, were made using a sand/cement/water ratio of 2:1:0.5 and

increasing the alkali content of the specimen to 2.5 and 3.5% by addition of

NaOH to the mixing water. After 24 hours of curing, specimens were demolded,

covered with a protective cover, and stored for 24 hours in a fog room at 230C.

Subsequently, specimens were autoclaved for 4 or 5 hours at 1270C.

4. Concrete prism test: Using a non-reactive basalt coarse aggregate, concrete

prisms were made using five sands and a concrete mixture consisting of 1 part

cement, 2.62 parts aggregate, 1.55 part sand, and a w/c of 0.46. The alkali content

of the cement was increased to 1.38 and 1.8%, and the cement content of the

concrete mixtures was set at 460 kg/m3. After 24 hours of curing, concrete prisms

were demolded, covered, cured in fog at 230C for 1 week, wrapped in a wet cloth

and plastic sheeting, and then stored at 400C and 100% R.H.

After gathering and analyzing all the data, the following conclusions were drawn

(Shayan, Ivanusec, and Diggins, 1994):

1. Results of the mortar bar test at 400C and 100% R.H. indicated that all five sands

are non-reactive which contradicted the results of ASTM C 1260.

2. An expansion limit of 0.20% at 14 days for the mortar bars stored in 1M NaOH

at 800C (ASTM C 1260) resulted in all aggregates being non-reactive and was

viewed as not effective. An expansion limit of 0.10% was found more effective.

3. ASTM C 1260 expansions of all sands exceeded 0.10% at ages between 10 and

17 days but were lower than 0.20%.

68

4. When evaluated using the proposed expansion limits for non-reactive aggregate

of 0.15, 0.33, and 0.48% at ages of 14, 28, and 56 days, respectively (Roger

1993), only one aggregate out of five was classified as reactive. These limits

were found to be not effective in identifying a number of known slowly reactive

aggregates (Shayan, et. Al. 1988).

5. Four out of the five aggregates were classified as slowly reactive using the

expansion results of the mortar bars stored in 0.75M NaOH at 800C.

6. Expansions of mortar bars in 0.50N NaOH at 800C classified all five aggregates

as non-reactive.

7. The testing conditions of the concrete prism test did not result in considerable

expansions for all the sands but one and that was after 40 weeks of storage.

8. The autoclave testing procedures resulted in a non-reactive classification of the

aggregates except of one sand.

9. The autoclave test, with 3.5% alkali content mortar bar autoclaved at 1270C for 4

or 5 hours, were not suitable for detecting slowly reactive aggregates.

10. The ASTM C 1260 procedures were effective in predicting the potential alkali

reactivity of slowly reactive aggregates which showed 10- to 17-day expansions

between 0.10% and 0.20%; however, the relevance of this method to field

concrete needs to be determined

4.3.2 ASR Preventive Measures

Shayan, Diggins, and Ivanusec (1996) conducted a long term, 6-years, study in

order to determine the effects of fly ash on ASR. They tested one innocuous

aggregate and six reactive aggregates. Two types of fly ashes with varying total

alkali content (0.01 and 6.30% Na2Oequiv.) and two types of cements were used. The

alkali content of the concrete was varied by adding NaOH to the mixing water.

Concrete specimens were formed and stored in a fog room at either 230C or 400C at

100% relative humidity. Expansions were monitored for nearly six years and several

69

mortar tests were performed. The results were as follows (Shayan, Diggins, and

Ivanusec, 1996):

1. The fly ashes tested were effective in preventing deleterious ASR expansions

when used in concretes with alkali contents as high as 7.0 kg Na2Oequivalent per m3

(1.4% Na2Oequivalent cement content); however, they only delayed damage in

concretes with alkali contents around 12 kg Na2Oequivalent per m3 (2.5%

Na2Oequivalent cement content). These alkali levels are outside the usual range of

concrete alkali levels in the field that vary between 0.60% to 1.20% Na2Oequivalent

cement content.

2. Long-term monitoring of concrete specimens is necessary to evaluate the

effectiveness of fly ash in reducing ASR damage.

3. The alkalinity of the pore solution of mortar cylinders was reduced significantly

by the use of fly ash. The reduction occurred faster for specimens stored at 400C

than those stored at 230C.

4. The accelerated mortar bar test (ASTM C 1260) can be used to predict the long-

term effectiveness of fly ash in controlling ASR expansion in concretes having an

alkali contents resulting in pore solutions having around 1M NaOH

concentrations which corresponds to concrete specimens at 1.38% alkali levels.

4.4 ASR IN BEIJING

The alkali-silica reaction in concrete is a new concern to the Beijing area. As the

concrete structures become older, more damage due to ASR is expected to be

identified (Peixing et al. 1996). After conducting extensive field surveys and

laboratory testing, it was concluded that most sands available in the Beijing area are

non-reactive (only a few samples were found to be reactive) while several coarse

aggregates were found to be responsible for most of the alkali-silica reaction

problems.

70

Testing procedures used in Beijing included ASTM C 227, C 1260, C 289, and

an autoclave method. Preventive measures practiced included (Peixing et al. 1996):

1. Routinely evaluating the reactivity of aggregates used in important concrete

structures using the above listed tests.

2. Limiting the total alkali content in concrete to 3 kg/m3.

3. Using low alkali mineral admixtures.

4.5 ASR IN CANADA

In Canada the alkali-silica reaction has been divided into two groups (CSA 1994):

1. Alkali-silica reaction with chalcedony, opal, cristobalite, glass, etc. which can be

usually identified using ASTM C 227. Concrete prisms expansion tests at 380C

using high cement content and high alkali content cement (ASTM C 1293) can

also be used to evaluate this type of reaction. ASTM C 289 can also be used;

however, this test might give misleading results when carbonates are present

(Rogers 1993).

2. Slow alkali-silica reaction associated with sandstones, granites containing

strained quartz, and metamorphosed sediments such as phyllite, argillite, and

greywacke. Conventional testing procedures such as ASTM C 227 and C 289 are

not suitable for evaluating this type of reaction. ASTM C 1293 is more

adequately used to identify these slow reactions (Rogers 1993).

4.5.1 Evaluating the Reactivity of Aggregates

A voluminous number of research studies have been completed in Canada for the

purpose of identifying and developing the ideal testing procedures for assessing

aggregates reactivity. The following is just a review of selective work conducted in

Canada.

71

4.5.1.1 “Testing Concrete for AAR in NaOH and NaCl Solutions at 380C and

800C (Berube and Frenette 1994).

In order to minimize the effects of storage conditions used with CSA A23.2-14A

(ASTM C 1293) and to accelerate the procedures, concrete prisms were tested in

NaCl and NaOH solutions at different temperatures. Two very reactive Canadian

aggregates were used: 1) a very fine-grained rhyolitic tuff and 2) a fine-grained

siliceous limestone. Non-reactive sand satisfying the requirements of ASTM C 1260

was used for mixture proportioning. Two types of cements were also used; one

having a high alkali content of 0.85% Na2Oeq and the other having an alkali content

of 0.54%. Concrete prisms, 75 mm x 75 mm x 300 mm, were made using the two

reactive aggregates in combination with the non-reactive sand. The concrete mixtures

had a water-cement ratio of 0.55 and incorporated 310 kg/m3 of the high alkali

content cement. NaOH was added to the mixing water in order to increase the alkali

content of the cement mass to 1.25% Na2Oeq (equivalent to a concrete alkali content

of 3.9 kg of Na2O/m3). Several concrete specimens were made using the low alkali

content cement in order to determine the effect of the initial alkali content of the

cement on the expansions. These specimens had a total alkali content of 1.7 kg/m3.

After fabrication, concrete prisms were stored, while still in molds, for 24 hours at

100% R.H. and 230C. Prisms were then demolded and cured for another 24 hours

under the same conditions. Two concrete prisms were stored under each of the

following conditions (Berube and Frenette 1994):

1. Tests in air at 100% RH and 380C: After curing was completed, concrete

specimens were immersed in water for 30 min., measured for the zero reading,

and then stored over water in sealed 22-liter plastic pails, with wicking, at 380C.

Before taking scheduled expansion readings, the sealed containers were stored

for 16 hours at 230C after which the specimens were immersed in water for 30

min. And then measured for expansion.

72

2. Tests in air at 100% RH and 800C: Specimens were stored over water in sealed

8-liter Rubbermaid R containers (two specimens per container) in an oven at

800C. The initial reading (zero reading) was taken after one day. All expansion

measurements were taken while specimens were still hot, as soon as they were

taken out of the oven.

3. Immersion tests in 1M NaCl solution at 38 or 800C: After curing, specimens

were immersed, in groups of two, in 1M NaCl solution (6% NaCl by mass), in

sealed 8-liter Rubbermaid R containers. Each container had 4.4 liters of solution,

for a volumetric solution/concrete ratio of 1.3 (1 prism = 1.7 liter). The

containers were then immediately stored in an oven at 800C or in a temperature-

controlled room at 380C. The zero reading was recorded the following day.

Expansion measurements were taken while specimens were still hot, as soon as

they were taken out of the oven or the temperature-controlled room.

4. Immersion tests in 1M NaOH solution at 38 or 800C: Same procedures as for

immersion tests in 1M NaCl solution at 38 or 800C were used.

5. Immersion tests in water at 38 or 800C: Same procedures as for immersion tests

in 1M NaCl solution at 38 or 800C were used.

The following conclusions and recommendations were documented (Berube and

Frenette 1994):

1. A relatively rapid ion migration exists, by diffusion, between the immersion

solution and the concrete pore solution.

2. Testing in 1M NaCl solution is not appropriate.

3. Testing in water resulted in a dilution of the alkalies in the pore solution of the

specimens and gave very low expansion results.

4. The initial concrete alkali content affected the rate of expansion of specimens

immersed in 1M NaOH solutions. Increasing the concrete alkali content to 1.25%

73

Na2Oeq of the cement mass was recommended.

5. While testing in 1M NaOH at 800C proved to be the most rapid concrete test

method, it was also proven that it is unreliable for determining the potential

alkali-reactivity of numerous aggregates.

6. The best concrete test method used 1M NaOH at 380C based on the following

reasons: a) it gave expansion results that are either similar or greater than the

results of the 100% RH test but in a significantly shorter term (about 6 months),

b) there was no alkali leaching from the concrete specimens, c) there was no

variation in the humidity conditions during one test and from one laboratory to

another, and d) since the chemistry of the concrete pore solution is controlled by

the curing solution, the effects of the water-cement ratio were minimized.

7. The recommended testing method to use for the evaluation of the potential alkali

reactivity of aggregate is the immersion of concrete prisms in 1M NaOH at 380C.

Prisms were made using a cement content of 310 kg/m3 and a water-cement ratio

between 0.50 and 0.55. The proposed criterion for identifying reactive aggregates

was 0.040% expansion or larger at 6 months.

4.5.1.2 “Effectiveness of High-Volume Fly Ash Concrete in Controlling

Expansion Due to Alkali-Silica Reaction (Fournier, Bilodeau, and

Malhotra 1994).

This study consisted of testing two alkali-silica reactive canadian aggregates,

siliceous limestone (Sp) and metagreywacke (Con), in combination with a local non-

reactive fine aggregate from granite. Properties of the aggregates are included in

Table 4.3.

The two reactive aggregates were tested for ASR in concrete mixtures containing

high- and low-alkali Type I portland cements and incorporating 56% of six selected

Canadian fly ashes. All high-volume fly ash mixtures had a nominal cementitious

74

materials content of 375 ± 10 kg/m3and water-to-cementitious materials ratio of

0.31 ± 0.01.

Table 4.3: Properties of Aggregates Investigated (Fournier, Bilodeau, and Malhotra 1994)

Aggregates

ID

Location

Type

Rock Type

Realtive Density (SSD), g/cm3

Absorption,

%

Expansion ASTM C 1260, %

14 day

28 day

Sp

Ottawa

Quarried

Rock

Siliceous limestone and traces of chert

2.69

0.48

0.356

0.625

Con

Halifax Quarried

Rock

Greywake

2.71

0.80

0.362

0.590

Fine

Aggregate

Cantley

Natural Sand

Derived from

granite

2.70

0.81

0.032

0.085

Concrete prisms, 75 mm by 75 mm by 300 mm, were made using variable

proportions and subjected to the following conditions:

1. 380C and relative humidity greater than 95%. Prisms were wrapped individually

in two damp sheets, placed in a plastic sleeve, and then placed vertically over

water inside a 25-L plastic pail with wicking materials on the sides.

2. 1M NaOH solution at 380C

3. 5% NaCl solution at 380C

4. 1M NaOH solution at 800C

Prisms subjected to conditions 2, 3 and 4 were stored in large polyethelene tubes

containing 24 prisms and the appropriate solution. The tubes were then placed in a

75

large tank filled with water and constantly maintained at the needed temperature.

Mortar bars were formed and tested according to ASTM C 1260.

The results of that study were as follows (Fournier, Bilodeau, and Malhotra 1994): 1. After evaluating the results and comparing expansions from the different storage

conditions investigated during this study, the following expansion limits in Table

4.4 were suggested.

Table 4.4: Proposed Limits for different Testing Conditions (Fournier, Bilodeau, and Malhotra 1994)

Storage/Testing Condition Proposed Expansion Limit

380C and R.H. > 95%: (Concrete Prisms)

0.04% at 52 weeks (CSA proposed limit) 0.04% at 104 weeks (mixtures with fly ash)

380C in 1M NaOH Solution: (Concrete Prisms)

0.04% at 26 weeks (control mixtures) 0.04% at 52 weeks (mixtures with fly ash)

380C in 5% NaCl solution: (Concrete Prisms)

Not Recommended (control mixtures) Not Recommended (mixtures with fly ash)

800C in 1M NaOH solution: (Concrete Prisms)

0.04% at 4 weeks (control mixtures) 0.04% at 8 weeks (mixtures with fly ash

800C in 1M NaOH solution: (Mortar Bars)

0.15% at 14 days (CSA proposed limit) 0.10% at 14 days (mixtures with fly ash)

2. Using the above expansion limits, it was possible to reliably evaluate the

potential alkali-reactivity of the tested reactive aggregates. The accelerated

concrete tests represented substantial acceleration compared to the proposed

standards.

76

3. The accelerated mortar bar test, ASTM C 1260, was successful in predicting the

effectiveness of the high volume fly ash replacement in controlling expansions

due to ASR. All the results generated using this accelerated mortar bar test

correlated very well to expansion results obtained from the different concrete

prisms testing conditions.

4. In concretes incorporating high volumes of fly ash, control of the expansions due

to ASR is dependent upon the chemical composition of the fly ash, in particular

its calcium and alkali content.

4.5.1.3 Inter-laboratory Test Evaluation

4.5.1.3.1 ASTM C 1260

Rogers (1996) reported a study with a purpose of developing a multi-laboratory

precision statement for the accelerated mortar bar test (ASTM C 1260). A Spratt

siliceous limestone from a quarry in Ottawa (Ontario) was tested by 46 laboratories.

It was found that the coefficient of variation in the 14-day expansion was 13.3%

when all laboratories used the same cement and 14.9% when each laboratory used a

different cement. Precision was stated as follows: “For mortars giving average

expansions after 14 days in solution of more than 0.30%, the muti-laboratory

coefficient of variation has been found to be 14.9%. Therefore, the results of two

properly conducted tests in different laboratories on specimens of a sample of

aggregate should not differ by more than 42% of the mean expansion (Rogers

1996).”

The CSA version of the test requires the use of a cement with a total alkali content

of 0.90 ± 0.10%. The ASTM version requires the use of a cement with an autoclave

expansion of less than 0.20%. The new recommended specification should be to use

any type of cement provided that when combined with the Spratt aggregate tested in

77

this study, it can produce 14-day expansions between 0.329% and 0.504% (Rogers

1996).

4.5.1.3.2 ASTM C 1293

Fournier and Malhotra conducted a study in order to determine the inter-

laboratory variation of the concrete prism test. The study consisted of testing two

reactive aggregates in combination with three non-reactive sands and Type 1

cements. The mixture designs were changed as well as the storage conditions of the

concrete prisms. A total of 27 laboratories, 24 from Canada, one from the U.S.A, and

two from France participated in the study. It was concluded that the between-

laboratory variability could be greatly reduced by using well-controlled testing

conditions or parameters such as “ a reference sand, a reference cement, a standard

storage container, and fixed concrete mixture proportioning.” It was also found that

the between-laboratory standard deviation and the coefficient of deviation of the test

prisms stored in 1M NaOH solution at 380C was significantly lower than the

coefficients of prisms under other storage conditions which included over water at

380C and 95% R.H (Fournier and Malhotra 1996).

4.5.2 ASR Preventive Measures

Thomas, Hooton, and Rogers (1997) outlined the guidelines recommended by the

Canadian Standards Association (CSA 1994) for preventing damage due to AAR in

new concrete construction. In order to minimize the risk of ASR in concrete, 1)

aggregates can be selected based on documented field performance, petrographic

examination, or satisfactory performance in a sequence of accelerated and long-term

expansion tests namely ASTM C 1260 (CSA A23.2-25A) and ASTM C 1293 (CSA

A23.2-14A) or 2) preventive measures can be adopted.

78

4.5.2.1 Field Performance (CSA 1994)

The best method for determining whether an aggregate is potentially reactive is to

examine the history of its field performance. An aggregate can be used in concrete

without any additional precautions providing that satisfactory field performance can

be demonstrated as follows (CSA 1994):

1. The cement content and the alkali content of the cement should be the same or

higher in the field concrete as is proposed in the new structure.

2. The concrete examined should be at least 10 years old.

3. The exposure conditions of the field concrete should be at least as severe as those

in the proposed structure.

4. A petrographic study should be conducted to demonstrate that the aggregate in

the structure is similar to that under investigation in the absence of conclusive

documentation.

5. The possibility of supplementary cementing materials having been used should

be considered.

6. The water-cement ratio of the concrete may affect performance.

4.5.2.2 Laboratory Studies (CSA 1994)

The laboratory testing procedures recommended by the CSA are listed in the

following Table 4.5. Figure 4.1 shows a flow chart that was proposed by Berube

(1992) for using these three testing procedures.

79

Table 4.5: Recommended Procedures and Limits to Detect Alkali-Reactive

Aggregates (Berube, 1992). Deignation

Name and Description Recommended Limits

ASTM C 295

Petrographic examination of aggregates for concrete

No limits but regarded as essential in interpreting results of other observations

CSA A23.2-25A (ASTM C 1260)

“Detection of alkali-silica reactive aggregate by accelerated expansion of mortar bars.” Mortar bars stored in NaOH solution at 800C. Can be used for coarse and fine aggregate.

Maximum of 0.15% at 14 days in solution (0.10% for some siliceous limestones, granites, gneisses, and some sandstones). Aggregate may still be used if it meets CSA A23.2-14A.

CSA A23.2-14A (ASTM C 1293)

“Potential expansivity of aggregates (length change of concrete prisms).” Concrete is made with cement content of 420 kg/m3 and 1.25% alkalis, stored at 38oC. Can be used for testing coarse or fine aggregate.

Maximum of 0.04% at 1 year, less than this (no value given) for critical structures such as dams and nuclear containment where small strains can cause excessive damage.

80

4.5.2.3 Preventive Measures (CSA 1994)

If an aggregate is classified as non-reactive using the above procedures then it can

be used in concrete without additional precautions. On the other hand, potentially

alkali-silica reactive aggregates should be used with appropriate preventive

measures. Recommended measures include:

Figure 4.1: Decision Chart for Determining Potential ASR Reactivity of Concrete Aggregates (Berube 1992).

81

1. Limiting the total alkali content of the concrete including alkalis from portland

cement and other sources to 3.0 kg/m3 Na2Oequivalent. Reducing the alkali content

of the concrete may be achieved by reducing the cement content, using a low

alkali content cement, or replacing part of the cement with a supplementary

cementing material.

2. Using supplementary cementing materials such as fly ash with a minimum

replacement level between 20 and 30% depending on composition or slag with a

minimum replacement level of 50%. Effectiveness of these materials with

specific cements should be checked using the long-term concrete prism test. The

total alkali content of the slag is limited to 1.0% while that of fly ash is limited to

4.5% Na2Oe. If these criteria are met, the contribution of the slag and fly ash to

the total alkali content of the concrete is considered to be zero.

3. Using silica fume, which is another potential cementitious material for reducing

the damage, caused by potentially reactive aggregates. However, there is no

guidance for its use with reactive aggregates. Additional investigations are

needed to determine the ideal use of silica fume for controlling ASR damage.

4.6 ASR IN CHINA

Alkali-silica reactive aggregates exist in China. Portland cements with an alkali

content as high as 1.20% Na2Oequiv. are used in China. In addition, chemical

admixtures are widely used to improve workability, strength, or other properties.

These admixtures usually add about 0.30-1.30 kg/m3 Na2Oequival. to the total alkali

content of concrete. In general, in North China, there are “absences of low alkali

portland cements and non-reactive aggregates (Tang et al 1996).”

4.6.1 Evaluating the Reactivity of Aggregates (Tang et al 1996)

Testing procedures used to evaluate aggregates’ reactivity include ASTM C 295,

C 227, C 289, and an accelerated autoclave method proposed by Tang et al. 1996.

82

The autoclave method is most widely used by engineers and researchers (Tang et al.

1996).

4.6.2 Preventive Measures

In order to minimize the risk of deterioration due to ASR, the maximum alkali

contents of concrete listed in Table 4.6 were proposed (Tang et al. 1996).

Table 4.6: Maximum Alkali Content (Tang et al., 1996)

Conditions of Circumstances

Maximum alkali content (kg/m3) in concrete Ordinary Structure Important Structure Special Structure

Dry No limit No limit 3.0 Wet 3.5 3.0 2.1

With alkali 3.0* Non-reactive aggregate Non-reactive aggregate * The structures should be effectively painted, otherwise non-reactive aggregates should be used

4.7 ASR IN FRANCE

4.7.1 Evaluating the Reactivity of Aggregates

Available French draft methods can be divided into three categories: 1) long-term,

mortar and concrete, accelerated expansion tests at 380C (P 18-585 mortar and P 18-

587 concrete), 2) ultra-accelerated expansion methods using mortar bars (P 18-588

and P 18-590), and 3) chemical method (P 18-589) (Criaux et al., 1994).

The long-term expansion test performed on mortar specimens (P 18-585) applies

to natural sands only. Sands containing high quantities of chert (potentially reactive

with a pessimum effect (PRP) aggregates) are not identified using these procedures.

The test is similar to ASTM C 227 with the following exceptions (Criaux et al.,

1994):

1. Test is only applicable to sand.

2. Sands are used as received and are not processed.

3. The alkali content of the cement is increased to 1.25% Na2Oequiv.

4. The mortar bars are stored in double containers maintaining a 100% humidity at

83

380C.

5. The proposed expansion limit is 0.10% at 6 months.

The long-term concrete prism test is similar to ASTM C1293 where the cement

alkali content is increased to 1.25% Na2Oeq and the cement dosage is 410 kg/m3.

Concrete prisms are formed using the coarse aggregate in combination with a pure

limestone sand. Prisms are stored at 380C and 100% RH. The proposed limit is

0.04% after 8 months of periodic expansion monitoring. It was conluded that this test

is not recommended for coarse aggregates containing more than 50% chert (Criaux et

al. 1996).

The microbar test (P 18-588) consists of grinding and sieving the sand or gravel

samples to the 160 to 630 µm fraction. Small mortar bars are cast using cement-

aggregate (c/a) ratios of 2, 3, and 10. The alkali content of the bars is increased to

1.5% of Na2Oeq. The bars are first cured for 4 hours at 100% R.H. and 1000C and

then submerged in a 10% KOH solution at 1500C for 6 hours. For each cement-to-

aggregate ratio (c/a), the final expansion is measured. The highest expansion among

the different c/a is compared to the threshold of 0.11%. For the exception of the

chert-rich aggregates, the expansion decreases with increasing c/a. The plot of

expansion versus the c/a ratio show the distinction between potentially reactive

aggregates and aggregates potentially reactive with pessimum (Criaux et al. 1996).

The kinetic test (P 18-589) consists of reducing the sand or gravel to the 0 to 300

µm fraction and subjecting it to a chemical attack by a 1M NaOH solution at 800C.

The SiO2 and Na2O concentrations in the solution are determined after 24, 48, and 72

hours. The values of SiO2/Na2O are plotted on a graph resulting in three reactivity

domains, non-reactive (NR), potentially reactive (PR), and potentially reactive with a

pessimum (PRP). This test method is not recommended for identifying the potential

84

reactivity of dolomitic limestones. It is however suitable for distinguishing between

PR and PRP aggregates (Criaux et al. 1994).

The first step in conducting the autoclave test (P 18-590) is to prepare the

aggregates in accordance with ASTM C 227. The alkali content of the mixtures is

increased to 4.0% Na2O. The mortar bars are first pre-cured in water for 24 hours and

then subjected to a 5 hours autoclave treatment at 1270C and 0.15 MPa. The

proposed expansion limit is 0.15% (Criaux et al. 1994).

According to the requirements of AFNOR P 18-542, the limits of the different

testing methods must be met to within ±10% uncertainty zone.

After testing nine sands and 20 coarse aggregates of various petrographic types

using all five testing procedures, it was concluded that there was good agreement

between the various test methods and between the tests and petrographic evaluation

of the aggregates. One exception was with the long-term mortar and concrete tests

used to evaluate chert-rich aggregates. Three types of aggregates were distinguished:

non-reactive (NR), potentially reactive (PR), and potentially reactive with pessimum

effect (PRP) with the latest (PRP) representing aggregates with more than 60% chert.

The following Table 4.7 includes some conclusions specific to each investigated

testing methods (Criaux et al. 1994).

4.7.2 Preventive Measures (Le Roux et al. 1996)

According to LeRoux et al. (1996) factors affecting the process of reducing the

risk of damage due to AAR include:

1. Alkali content of the concrete

2. Type of aggregates

3. Type of cement

85

4. Environment conditions

5. Acceptable level of risk

Table 4.7: Summary of the Different AFNOR Testing Procedures (Le Roux et al. 1996)

AFNOR Method

Testing Method

Na2Oeq by

weight of

cement

Dimensions of Specimens

(cm)

Materials Tested

Proposed Limits and diagnosis

P 18-585 Mortar bar test (modified C 227)

Expansion test on mortar at 380C and 100% R.H.

1.25%

2.5x2.5x28

Sand only

0.10% at 6 months PR or NR

P 18-587 concrete prism test (C 1293)

Expansion test on concrete prisms at 380C and 100% R.H.

1.25%

7x7x28

Gravel only

with NR sand

0.04% at 8 months PR or NR

P 18-588 Microbar test

Expansion test on mortar bars at 3 cement/aggregate ratios; pre-cure at 1000C, 100% R.H. (4h); cure at 1500C in KOH 10% (6h)

1.50%

1x1x4

Sand or coarse

aggregates

0.11% and curve of expansion vs. C/a PR, PRP, or NR

P 18-589 Kinetic test

Chemical and kinetic test at 800C in 1M NaOH; SiO2/Na2O measured at 24, 48, and 72 h.

Not applicable

Sand or coarse

aggregate

3 zones on a graph

P 18-590 Autoclave test

Expansion test on mortar bars; pre-cure in water (24 h); cure at 1270C, 0.15 MPa, in autoclave (18 h).

4.0%

4x4x16

Sand or coarse

aggregate

0.15% PR or NR

Petrography

Binocular, optical microscopy on thin sections, point counting, scanning electron microscope, chemical analysis, XRD

Sand or coarse

aggreagte

Presence of reactive silica NR or PR

86

The following sections include a summary of the French code of practice

regarding ASR.

4.7.2.1 Alkali Content of the Concrete (Le Roux et al. 1996)

The threshold alkali content recommended by the French Ministry of Equipment

and Transportation is 3.0 kg/m3 of concrete.

4.7.2.2 Acceptable Level Of Risk And Environment Conditions (Le Roux et al.

1996)

The following Table 4.8 categorizes structures according to their environment and

characterization (location, strategic and economic importance, size, purpose, etc.).

“The Employer is responsible for the decision as to which category the structure

belongs to” (Le Roux et al. 1996).

Table 4.8: Level of Prevention as Determined by the Category and Exposure of the Structure (Le Roux et al. 1996)

Environment Class Category of Structure

1 dry or not very damp

2 damp to

wet

3 damp with frost and

deicing salts

4 maritime

environment

I Slight risk Acceptable A A A A II Risk not very acceptable A B B B III Risk Unacceptable C C C C

The following are definitions of the different levels (Le Roux et al. 1996):

Level A: No special precautions with respect to the alkali-aggregate reaction are

necessary. The only requirements are the usual rules of construction.

Level B: In this case, which is the most common (it applies to most civil engineering

works), there are theoretically six possibilities allowing the use of potentially

87

reactive aggregates, They allow the use of aggregates of all types, and satisfying the

conditions of one of the possibilities eliminates the risk.

Level C: In this case, non-reactive aggregates (NR), or else aggregates characterized

as potentially reactive with pessimum effect (PRP), may be used in the concrete.

Methodology used for Level B prevention is summarized in Table 4.9.

Table 4.9: Methodology Used for Level B Prevention (Le Roux et al. 1996)

Question 1 Question 2 Question 3 Question 4 Question 5 Question 6 Does the quarry documentation show that the aggregates are non-reactive?

Does the formulation satisfy an analytical criterion (assessment of alkalis)?

Does the formulation satisfy a performance criterion (swelling test)?

Is the formulation accompanied by sufficiently convincing references of use?

Does the concrete contain mineral addition in sufficient proportions?

Are the conditions specific to PRP aggregates met?

Questions 1 and 4 are based on statistical data that the aggregate producer is

supposed to supply.

Formulation of Planned Concrete

The concrete formulation is accepted

The concrete formulation must be modified

Yes to one of the questions

No to all of the questions

88

Question 2 is concerned with the determination of the active alkalis contained in

a sample of cement, Tm, which should not exceed the specified threshold of 3.0

kg/m3.

VcTm

215.3

+< (Eq 4.1)

Where “Vc is the ratio of the standard deviation to the mean of the active alkali

content values observed over the last 12 months output.” The active alkali

content of the aggregates is determined by submerging the aggregates in boiling

lime water and measuring the dissolved alkalis after 7 hours. The active alkalis of

blended cements are determined using either of two methods:

1. Using a formula: If the proportions of the various components of the cement

are known, then the active alkalis are obtained by adding “together the alkalis

from the individual constituents in proportion to the contents of each in the

cement and weighting the alkalis by an activity coefficient determined by the

type of constituent. The coefficients used are 0.5 for slags and calcareous

fines, 0.17 for fly ash and pozzolans, and 1.0 for clinker and gypsum.”

2. Using an experimental method: By attacking the blended cement with a weak

acid (HNO3 1:50), it is possible to determine the soluble alkali content (As)

and the insoluble residue content (R). The active alkali content (A) is then

determined by the formula:

AsR

RJJAsAtA−

−+−+−=

1)(5.0)1()(17.0 (Eq 4.2)

where

At = total alkali content of the cement

J = content of the constituents other than clinker (slag, ash, pozzolans, etc.)

89

Question 3 calls for using an accelerated test method to check that the concrete

mixture proposed will not exhibit deleterious ASR. The measured expansions

during this test should be less than the maximum allowed expansions. The testing

procedure to be used is P 18-587 (Table 4.7), but the temperature should be

increased to 600C. The maximum allowable expansion is 0.02% at 3 months if

the following aggregates are used:

1. Massive Rocks: sandstones, limestones, quartzites

2. Alluvial Deposits: Silico-calcareous alluvia, calcareous alluvia, flints,

siliceous concretions, cherts.

For all other types of rocks, the maximum allowable expansion is 0.02% at 5

months. Exactly the same concrete mixture proposed for use in the structure

should be used for fabricating the testing specimens. However, to count for the

variability of the alkali content in the field concrete, the alkali content of test

specimens should be adjusted by adding NaOH without changing the water-

cement ratio. The quantity of NaOH to be added (δ) should be calculated as

follows (Le Roux et al. 1996):

])21([ AechVcAmC −+=δ kg/m3 (Eq 4.3)

where

C = cement content in kg/m3

Am = mean active alkali content of cement

Vc = coefficient of variation of the alkali content of the cement

Aech = active alkali content of the sample of cement in the specimens

If Am and Vc are not available than the following equation should be used:

90

AechC ××= 25.0δ (Eq 4.4)

1.29δ kg/m3 of NaOH should be added. If δ is negative, then no additional NaOH

is required.

Question 6 deals with flint aggregates which usually are potentially reactive with

pessimum effect (PRP). These aggregates can be used for a Level C structure.

The following conditions have to be met in order for the aggregate to be

acceptable for use:

Condition 1:

− Either the concrete contains only PRP aggregates (PRP sand, PRP

gravel);

− The mixture, composed of aggregates separately classified as NR, PR, or

PRP, is characterized as PRP. The mixture has to be checked using

either NF P 18-588 or NF P 18-589 (Table 4.7).

Condition 2:

− Using the counting procedures, the granular mix is found to contain

more than 60% flint by mass;

− Or the 8-month expansion of specimens made with the proposed

aggregates, is less than 0.04% when tested with the procedures of the

modified NF P 18-587 (Table 4.7).

The flow chart shown in Figure 4.2 represents the procedures followed for

assessing the reactivity of aggregates. This approach was evaluated by applying it to

different aggregates used in existing very old deteriorated structures.

91

4.8 ASR IN THE NETHERLANDS

According to Heijnen et al. (1996), the number of the structures affected by ASR

in the Netherlands has increased from 3 to 35 from 1991 to 1996. Most of these

structures were between 30 and 60 years old, which suggested that the rate of ASR in

this country is relatively slow. This was attributed to “the nature of the reactive

Figure 4.2: Flowchart of Testing Procedures Used to Evaluate Aggregate Reactivity (Le Roux et al. 1996)

92

components (coarse porous chert grains) of the aggregates, the relatively low

content of potentially reactive aggregate particles, the generally low cement content

of Dutch concrete, and the generally low alkali content of Dutch portland cement

(Heijnen et al. 1996).” Two concrete structures incorporating low amounts of slag

(about 40% by mass of cement) were identified as being damaged due to ASR.

4.8.1 Evaluating the Reactivity of Aggregates

In the Netherlands, petrographic examination is the major test used for identifying

the susceptibility of aggregates to ASR. Petrographic examination, in combination

with PFM and point-counting analysis, are used on a routine basis. Concrete

aggregates are separated based upon their mineralogical composition (Heijnen et al.

1996):

1. Aggregates with such a low amount of reactive components that no harmful ASR

can occur, indicated as “under critical”

2. Aggregates with such a high amount of reactive components that no harmful

ASR can occur, indicated as “above critical”

3. Aggregates with an amount of reactive components that harmful ASR can occur,

indicated as “critical”.

4.8.2 Preventive Measures

In the Netherlands, determining the potential ASR reactivity of aggregates is of

minor importance. This is due to the belief that “concrete mix design and cement

type can be chosen in such a way, that the risk of harmful ASR is negligible (Heijnen

et al 1996).” More than 70% of all concrete produced in the Netherlands incorporate

one of the following cements, which are assumed to prevent damage due to ASR

(Heijnen et al 1996):

1. Portland blast furnace slag cement with more than 65% (by mass) slag and an

alkali content less than 2.0% (by mass)

93

2. Portland blast furnace slag cement with more than 50% (by mass) slag and an

alkali content less than 1.1% (by mass)

3. Portland fly ash cement with more than 25% (by mass) fly ash and an alkali

content less than 1.1% (by mass).

4.9 ASR IN KOREA

Deterioration of concrete structures due to ASR has been mitigated in Korea by

using relatively low alkali cement, as low as 0.50% (Yangsoo et al. 1996). Forty

samples of crushed stones used by the ready mix concrete plants in Korea were

investigated using petrographic analysis (XRD, SEM, and polarized light

microscope), ASTM C 289, and ASTM C227 while varying the alkali content of the

mortar bars. Several aggregates were identified as being reactive which corresponded

well with their bad field performance. ASR is starting to be a problem in several

concrete structures in Korea (Yangsoo et al. 1996).

4.10 ASR IN NORWAY

4.10.1 Evaluating the Reactivity of Aggregates

In order to determine the alkali-silica reactivity of Norwegian concrete

aggregates, two consecutive test methods are performed namely a petrographic

analysis (Norwegian method) and the South African accelerated mortar bar test

(ASTM C 1260) (Jensen 1996). Up to 1993, the concrete prism test (ASTM C 1293)

was considered a reliable method, but is no longer suitable for evaluating the alkali

reactivity of sandstones and phyllite and concrete aggregates in general (Jensen

1996).

94

4.10.1.1 Petrographic Analysis (Jensen 1996)

An improved version of the ASTM C 295 petrographic analysis method was

developed to classify concrete aggregate samples. The method is based on point

counting of thin sections and is used with natural sand, coarse gravel, and crushed

stone. “Rock types are then classified according to geological nomenclature,

microstructure of the rock, degree of deformation and alteration. Results are reported

as volume percentage of major rock/minerals in addition to alkali reactivity based on

field experience.”

Rocks have been divided into three categories:

1. Reactive Aggregates: Sandstone, siltstone, cataclastic rocks, acid volcanic rocks,

argillaceous rocks, greywake, marl and rock types with microcrystalline quartz

(grain size less than 0.06 mm).

2. Potentially reactive aggregates: Fine grained quartzite or rock types containing

micro-very fine-grained quartz (crystal size 0.06 - 0.13 mm).

3. Innocuous aggregates: Gneiss, granite, coarse-grained quartzite, crystalline

limestone, gabbro, and rock types with coarse grains and/or minor amounts of

quartz.

Aggregates containing more than volume 20% reactive + potentially reactive

rocks are classified as alkali reactive. Aggregates containing less than volume 20%

reactive + potentially reactive rocks are classified as innocuous.

4.10.1.2 NBRI Accelerated Mortar Bar Test (ASTM C 1260)

This test is the same as the ASTM C 1260 test with 14-day expansions higher than

0.10% representing reactive aggregates and lower than 0.10% representing

innocuous aggregates (Jensen 1996).

95

4.10.1.3 The Concrete Prism Test (ASTM C 1293)

This concrete prism test is identical to ASTM C 1293 (Jensen 1996).

4.10.1.4 Testing Protocol

In order to identify the reactivity of an aggregate, the first step should be to

perform the petrographic analysis. If the aggregate contains less than volume 20%

reactive plus potentially reactive rocks then the aggregate is innocuous and no further

testing is required. If the aggregate contains more than 20% volume reactive plus

potentially reactive rocks then it is recommended but not required to perform the C

1260. If the aggregate exhibits 14-day expansion higher than 0.1% than it is

classified as reactive. It is noted that the C 1260 test “overrule the result from the

petrographic analysis (Jensen 1996).”

The concrete prism test (C 1293) is no longer recommended because of its

inability to correctly identify the alkali reactivity of sedimentary rocks for which the

test classified the aggregates as being innocuous when they were shown reactive in

the field (Jensen 1996).

4.10.2 Preventive Measures

Specifications for minimizing the risk of damage due to AAR are limited in

Norway. “The Norwegian NS 3420, L5 from 1986, dealing with aggregates for

concrete, specifies that reactive aggregates in harmful amounts are not to be used in

concrete (Jensen 1996).”

4.11 ASR IN PORTUGAL

In Portugal, only a few cases of ASR deterioration have been reported. As a

result, little attention has been allocated to research the reaction in concrete. As the

structures become older, more cases of ASR damage are becoming evident. Work

geared towards identifying the ASR in damaged structure and mitigate the reaction in

96

other structure is a task that is being performed. Work has been completed to

evaluate the geology and lithology of aggregates used in concrete. A map showing

the different aggregates produced in Portugal and showing their degree of reactivity

have been produced (Silva et al. 1996).

4.12 ASR IN NEW ZEALAND (St John and Freitag 1996)

Volcanic aggregates are the most abundant aggregates in New Zealand and their

reactivity has been recognized since 1943. The current New Zealand code of practice

for minimizing damage due to AAR requires the use of low-alkali cement and low

total soluble alkali content of concrete. This approach was considered adequate for

most concretes until recently when “the number of structures identified with AAR

has increased”. Some of the problems with this approach includes 1) errors in

determining the alkali content of a concrete and 2) even if the analytical results are

correct, the alkali content of the concrete might change due to the alkalis present in

the environment.

Work has been performed by the author to come up with chemical techniques

capable of estimating the original alkali content of concrete. This analytical process

has been verified with the investigation of concrete samples obtained from structures.

It was noticed that the alkali content of the investigated concrete increased during the

life of the structure causing AAR damage even though low alkali content cement was

used as specified. The change in the alkali content was blamed on the leaching of

alkalis from some New Zealand basalt.

Concerns about the effectiveness of silica fume in reducing damage due to AAR

were noted. Expansive cracking due to AAR was produced in test specimens

containing New Zealand cements and aggregates and subjected to wetting and drying

and outdoor exposure.

97

Most of the work concerned with AAR in New Zealand has been concentrated on

field structures. Very little work has been accomplished in the laboratory for the

purpose of investigating test methods for predicting the reactivity of aggregates.

4.13 ASR IN HONG KONG (Tse and Gilbert 1996)

Due to the rapid growth in construction, Hong Kong’s construction industry had

to depend on local aggregates of granitic origins and on imported aggregates of

mostly volcanic tuff origins. The AAR problem is still new to Hong Kong. Field

investigations have concluded that ASR is the cause of deterioration in several

structures including sewage treatment plants. Research is currently undertaken by

several universities in order to investigate the AAR problem.

In order to minimize the AAR damage caused by using local and imported

aggregates, the Hong Kong government is specifying a 3 kg/m3 limit on the reactive

alkali content of concrete for government projects. This specified limit has been used

for all engineering and building works contracts since 1994.

4.14 ASR IN TAIWAN (Yen et al. 1996)

Forty-four aggregate sources used in Taiwan have been investigated for alkali

silica reactivity using ASTM C 289, ASTM C 227, and ASTM C1260. It was

concluded that

1. C 227 underestimates aggregates reactivity of most reactive aggregates tested,

and

2. C 1260 overestimated the reactivity of several aggregates.

98

4.15 ASR IN ITALY

ASR has been a matter of concern in Italy. Several investigations have been

geared towards investigating the validity of accelerated testing procedures in

predicting the reactivity of aggregates and the effectiveness of mitigation

alternatives. The most recent work has been conducted by Berra, De Casa, and

Mangialardi (1996) and Berra, Mangialardi, and Paolini (1994).

Berra et al. (1996) used two alkali-reactive aggregates to investigate the

effectiveness of the C 1260 test procedures in predicting the effects of using

supplementary cementing materials (SCM), particularly, silica fume and fly ash.

Tests performed included measurements of expansions, water permeability, pore

liquid composition, and Ca(OH)2 content. It was concluded that the testing

procedures are adequate for evaluating the effectiveness of SCM in reducing the risk

of ASR damage. The test is “suitable to accelerate the pozzolanic reactions of SCMs

such as condensed silica fume and pulverized ash.” It was also concluded that the

pozzolanic reaction causes a decrease in OH- ion concentration in the pore solution

of the mortar bars, which is caused by the reduced permeability and the incorporation

of alkali hydroxides. The decrease in OH- is responsible for the reduction in the

expansivity of alkali-reactive aggregates (Berra et al., 1996).

Berra et al. (1994) investigated the use of ASTM C 1260 in assessing the

effectiveness of fly ash and silica fume in reducing expansions caused by the alkali-

silica reaction using fused quartz as a reactive aggregate. Results of the C 1260 test

were compared against the long-term results obtained form C 227. A good

correlation was found between the results of both tests. C 1260 provided adequate

minimum contents of fly ash and silica fume needed to prevent deleterious ASR

expansions. For silica fume, it was found that the two tests provided comparable

results when the expansion limits for C 1260 and C 227 were respectively 0.25% at

99

12 days and 0.10% at 1 year or alternatively, 0.15% at 14 days and 0.05% at 1 year.

Results from both tests did not indicate that there is a relationship between the alkali

content of the fly ash and its performance in reducing ASR expansions (Berra et al.,

1994).

4.16 ASR IN ICELAND

Between 1861 and 1979, alkali aggregate reaction was identified as the main

cause of damage to many concrete structures (mostly housing) in Iceland. As a result,

using silica fume as a partial replacement of cement was required in order to mitigate

the problem. Twenty years later, no AAR damage has been noticed in concrete

structures. It was concluded that using silica fume is an effective method for

preventing damage due to AAR (Gudmudsson and Olafsson 1996, 1999).

4.17 ASR IN THE UNITED KINGDOM OF BRITAIN

To minimize the risk of damage due to alkali-aggregate reaction in concretes

containing reactive aggregates, current UK guidelines permit the use of fly ash

(Thomas Blackwell, and Nixon, 1996). However, definite advice on how to use the

fly ash in concrete and what percentages to use are not included in the guidelines

(Concrete Society, 1992). This is because there exists conflicting evidence regarding

the alkali content of the fly ash and whether they are available for reacting with the

aggregate causing additional damage (Thomas, Blackwell, and Nixon, 1996). This is

specifically a problem in case the total alkali content of the concrete is being

controlled below a certain level in order to prevent AAR damage. Several

recommendations exist on how to deal with the alkali content of fly ash:

1. The Concrete Society (UK) recommends using the water-soluble alkali content of

the fly ash for determining the total alkali content of the concrete (Concrete

Society 1992).

100

2. The Building Research Establishment (UK), Department of Transport (UK),

French Guidelines, and Ireland guidelines recommend using one-sixth of the total

alkali content of the fly ash to calculate the total alkali content of the concrete.

This is a more conservative approach since 0.40% to 0.70% Na2Oequiv. is

equivalent to 0.10% water-soluble alkali content (BRE 1988, Department of

Transportation (UK) 1992, Thomas et al. 1996).

In the UK the belief is that the use of sufficient levels of Class F fly ash is

effective in preventing ASR expansions in concretes containing natural reactive

aggregates even when the alkalis from sources other than the fly ash are enough to

cause deleterious expansions in concretes without any fly ash (Thomas, Blackwell,

and Nixon 1996). In this case, the fly ash is considered to have a positive effect and

to have no reactive alkali contribution. However, when moderate levels of fly ash

are used in concrete containing very rapidly reactive aggregates with low alkali

content cements, then the fly ash will likely contribute alkalis to the reaction. In this

case higher replacement levels may be required in order for the fly ash to completely

prevent the reaction from occurring (Thomas, Blackwell, and Nixon 1996).

In a study reported on by Thomas, Blackwell, and Nixon (1996), five reactive

aggregate sources from the UK area were used to make concrete specimens using

one high-alkali portland cement (1.15% Na2Oe) and three Class F fly ashes with

varying total alkali content (2.98, 3.46, and 3.86% Na2Oe). Fly ash was used at

different replacement levels and concrete prisms were stored in plastic containers at

200C and 100% relative humidity. At 7 days, length measurements of all prisms were

taken before wrapping them in moist toweling and polyethylene. Some of the

wrapped prisms were stored at 200C while some were stored at 380C, all at 100%

humidity. For the particular materials used in this study (UK reactive aggregates and

101

UK Cement and Class F fly ash) it was determined that (Thomas, Blackwell, and

Nixon, 1996):

1. The effective alkali contribution of the fly ash depends upon the nature of the

reactive aggregate and the levels at which the weight of cement is replaced with

the fly ash.

2. The alkali content of concrete in the control specimens (neglecting the alkalis in

the fly ash) was enough to cause deleterious expansions and cracking of

specimens containing moderately reactive flint. Replacing the cement with 25%

fly ash was effective in reducing expansions. As a result, it was noted that the fly

ash has a positive effect in reducing damage due to ASR and does more then just

dilute the alkalis in the cement. Using the same reactive aggregate but replacing

6% of the cement with fly ash resulted in an increase in expansions for a given

cement alkali content. It was determined that 40% of the total alkalis in the fly

ash contributed to the expansions of concrete specimens.

3. Replacing 25% of the cement weight with fly ash was not effective in preventing

excessive expansions and cracking of specimens containing rapidly reactive

aggregates (i.e. aggregates that cause deleterious expansions with low alkali

content cement). These aggregates required using 35% fly ash by weight. The

contribution of the total alkalis in the fly ash to the expansions was estimated to

be 10%.

4. It is inappropriate to use a singular value (e.g. one-sixth of the total alkali content

in ash) to estimate the contribution of the alkalis of the fly ash to the rate of ASR.

It is dependent upon the aggregate nature and levels of replacements. In addition,

using this approach ignores mechanisms, other than the alkali availability, that

contributes to the efficiency of the fly ash in reducing ASR damage.

5. Specifications for using fly ash as an ASR mitigation alternative should take into

consideration that highly reactive aggregates require higher amounts of fly ash in

102

the mixture. As the calcium content of the fly ash increases (Class C fly ash), the

amounts of the fly ash used in the concrete should also be increased.

4.18 ASR IN THE UNITED STATES OF AMERICA

In his 1996 paper, Hooton (1996) discussed the current status of aggregate testing

for ASR in the USA. He mentioned that ASTM C 227 and C 289 are no longer

considered reliable and are no longer used for assessing aggregate reactivity. The two

tests that are gaining popularity are ASTM C 1260-94 (CSA A23.2-25A-M94) and

ASTM C 1293-95 (CSA A23.2-25A-M94). The following are some points about the

tests (Hooton, 1996)

ASTM C 1260: Accelerated Mortar Bar Test (Hooton 1996)

1. Effect of cement: This test is only used for determining the potential reactivity of

aggregates and not to evaluate cement-aggregate combinations. The alkali

content of the cement does not have a significant effect on the test expansions.

This is due to 1) the bars are immersed in the 1M NaOH solution at the early age

of 2 days allowing the alkalis to rapidly reach the aggregate, 2) specimens are

stored at 800C which greatly accelerates the reaction, and 3) the 1M NaOH

solution represent a much higher pore solution alkalinity than what can be

reached with normal high alkali, high content cement concrete.

2. Use for evaluating the effectiveness of Supplementary Cementing Materials

(SCM): Both ASTM C 1260 and CSA A23.2-25A test methods do not suggest

using the test for evaluating the effectiveness of SCM.

3. Interpretation of Expansions: Proposed limits are 0.15% after 14 days, 0.33%

after 28 days, and 0.48% after 56 days of testing. Thus, an aggregate has to show

expansions lower than these three criteria in order to be innocuous. Aggregates

cannot be rejected based solely on C 1260 results although they can be accepted.

4. Possibilities for Modifications: The work conducted by Starks (1993) and

103

discussed later in this chapter was suggested as being a potential modification

for the ASTM C 1260 procedures.

ASTM C 1293: Concrete Prism Expansion Test (Hooton 1996)

The test results relate well with observed field performance. The 12-month

duration of the test is a concern, but is required for accurate results. Accelerated

results can be achieved by raising the temperature or other changes. However,

acceleration of test may have undesirable side effects.

Hooton (1996) concluded that if an aggregate was classified as potentially

reactive when tested according to ASTM C 1260, it should be checked using C 1293

before finally concluding the aggregate reactivity. In addition, he mentioned that

ASTM needs to develop a document as guidance for the use of C 1260 and C 1293.

4.18.1 DOT Survey

A survey of the DOTs was conducted to determine the status of ASR in the U.S.

The following were the conclusions of the survey (Figure 1.1):

1. ASR exists nationally in the U.S.

2. ASTM C 1260 and C 1293 are the two tests that are used the most. One DOT

reported the use of a modification of the C 289 test.

3. Low alkali cement, Class F fly ash, and slag are the most popular mitigation

methods.

4.18.2 Strategic Highway Research Program (SHRP)

Starks (1993) conducted the most extensive aggregate testing work in the USA as

part of a Strategic Highway Research Program (SHRP) study. Throughout the study,

11 aggregates found to be reactive in field applications and 5 aggregates known to be

innocuous were investigated (Table 4.10). After examining the results of ASTM C

104

227 and C 289 performed on the aggregates listed in Table 4.10, it was concluded

that these two tests are inadequate for detecting slowly reactive aggregates and that a

rapid and more reliable ASR test procedure is needed. ASTM C 1260 was the test

that was chosen to be investigated in this study (Starks, 1993).

Aggregates were prepared in accordance with the requirements of C 227. Four

mortar bars were then made using (1) Type I cement, with 1.0-percent equivalent

Na2O, (2) an aggregate to cement ratio of 2.25:1.00, and (3) a fixed water to cement

ratio of 0.50. Mortar specimens representing each aggregate were then stored in

NaOH with varying normalities namely 1M, 0.75N, 0.52N, 0.35N, and 0.18N. The

varying levels of normalities were used in order to determine a cement alkali level

below which the aggregates do not exhibit deleterious expansions. This was

achieved by using the following equation (Starks, 1993):

LmolescwONaOH /06.0022.0

/2339.0][ ±+=− (Eq 4.4)

In equation 4.4, [OH-] corresponds to NaOH normality, Na2O represents the

percent Na2O equivalent of the cement, and w/c is the water-cement ratio. This

equation was developed during the SHRP-342 study (Helmuth 1993). After

examining data from the literature (Diamond 1989, Nixon and Page 1987, Canham

and Page 1987, Kawamura, Kayyali, and Hague 1988, and Larbi and Bijen 1990)

equation 4.4 was developed and justified.

105

Table 4.10: Aggregate Sources Investigated Throughout the Study (Starks, 93) Source Identity

Source Area

Aggregate Type

Field Performance

Deleterious

AL Albuquerque, NM Mixed sand and gravel, rhyolite to andesite

Rapidly reactive with low alkali cement

BK Bennettsville, SC Quartz, quartzite gravel, reactive quartzite

Slowly reactive with high alkali cement

GH Salisbury, NC Quarried Argillite Slowly reactive with high alkali cement

GR Carlottesville, VA Quarried metabasalt Slowly reactive with high alkali cement

OR Barstow, CA Mixed sand and gravel, reactive rhyolite to andesite

Rapidly reactive with low alkali cement

PR Princeton, NC Quarried granite to granite-gneiss

Slowly reactive with high alkali cement

RH Carlottesville, VA Quarried granite-granite gneiss

Slowly reactive with high alkali cement

RQ Montgomery, Al Mixed sand and gravel, reactive chert and quartzite

Reactive with low alkali cement

SF Wilmington, DE Quarried granite-gneiss to amphibolite

Slowly reactive with high alkali cement

SX Sioux Falls, SD Quarried quartzite Slowly reactive with high alkali cement

TM Petersburg, VA Mixed sand and gravel, reactive chert and quartzite

Slowly reactive with high alkali cement

WR Trenton, NJ Mixed sand and gravel, reactive chert, quartzite, granite gneiss

Slowly reactive with high alkali cement

Innocuous

DR St. Paul, MN Quarried gabbro-diabase Non-reactive with low alkali cement

EC Eau Claire, WI Mixed siliceous sand and gravel

Non-reactive with low alkali cement

EL Chicago, IL Mixed carbonate and siliceous sand and gravel

Non-reactive with low alkali cement

ML Rock Island, IL Quarried Limestone Non-reactive with low alkali cement

TH Chicago, IL Quarried Dolomite Non-reactive with low alkali cement

TR Central New Jersey Quarried gabbro-diabase Non-reactive with low alkali cement

106

It was concluded that aggregates showing 14-day expansions exceeding 0.08%

should be classified as being potentially deleterious aggregates. Aggregates showing

14-day expansions lower than 0.08% can be classified as innocuous. One notable

exception, a mixed siliceous aggregate, was reported to be innocuous in field

performance and showed a 14-day expansion of 0.278% (greater than 0.08%). This

abnormality was considered to reflect “the fact that observed satisfactory field

performance was based on use with high alkali cements that produce pore solutions

in concrete less alkaline than the 1M solution used in the test (Starks, 1993)”.

Results are listed in Table 4.11.

Other conclusions included (Starks, 1993):

1. The immersion test (C 1260) can be used to estimate maximum cement alkali

levels at which deleterious ASR is not very probable. This is accomplished by

using equation 4.4 and changing the normalities of the curing NaOH solution.

2. When changing the normality of the curing solution, “the test criterion must be

adjusted progressively downward to a minimum of about 0.02 percent as solution

normality decreases to about 0.6N (Figure 4.3).”

3. The test procedures combined with a criterion of 0.08 percent expansion at 14

days can be effectively used to determine the mineral admixture requirements for

preventing deleterious ASR.

4. The C 1260 procedures did not result in accurate results when concrete prisms

were used. When the molarity of the solution changed from 1M to 0.70N and

0.35N the expansion of the concrete prisms decreased as expected. However, one

innocuous aggregate showed expansions higher than several reactive aggregates.

As a result, it was concluded that these procedures are not dependable for testing

concrete prisms.

107

Table 4.11: Results of the C 1260 Test (Starks, 1993)

Source Composition

C 1260 Expansion, % 4

Days 7

Days 10

Days 14

Days 21

Days 28

Days Deleterious in Field Performance

AL Granitic Volcanic 0.190 0.483 0.713 0.867 1.035 1.098

OR Granitic Volcanic 0.205 0.296 0.375 0.424 0.500 0.541 GH Argillite 0.080 0.252 0.354 0.418 0.511 0.566 RQ Chert, Quartzite 0.070 0.212 0.328 0.409 0.515 0.574 WR Chert, Quartzite 0.073 0.160 0.246 0.314 0.416 0.487 PR Granitic Gneiss 0.108 0.189 0.239 0.309 0.385 0.422 SX Quartzite 0.069 0.122 0.170 0.225 0.312 0.389 TM Chert, Quartzite 0.032 0.066 0.116 0.177 0.270 0.309 BQ Chert, Quartzite 0.042 0.063 0.073 0.106 0.142 0.196 RH Granitic Gneiss 0.013 0.032 0.065 0.096 0.132 0.164 SF Granitic Gneiss 0.044 0.038 0.064 0.086 0.124 0.146 GR Metavolcanics 0.026 0.040 0.052 0.082 0.115 0.146

Innocuous in Field Performance ML Limestone 0.025 0.024 0.029 0.026 0.035 0.024 TH Dolomite 0.028 0.047 0.066 0.066 0.077 0.078 TR Gabbro 0.014 0.022 0.029 0.044 0.066 0.102 EC Mixed Siliceous 0.055 0.076 0.181 0.278 0.329 0.388 DR Gabbro 0.032 0.027 0.061 0.075 0.157 0.263

108

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10

0.00 0.20 0.40 0.60 0.80 1.00

NaOH Solution Normality

14-D

ay E

xpan

sion

, per

cent

TR (Innocuous)TH (Innocuous)SF (Deleterious)GR (Deleterious)WR (Deleterious)

0.00 0.23 0.52 0.82 1.1 1.4 Corresponding Cement Alkali

Equivalent Na2O (From Equation 4.4)

Figure 4.3: Failure Criteria for Determining Safe Cement Alkali Level for Deleterious Aggregates Using ASTM C 1260 (Starks 1993)

109

4.18.3 ASR in North Carolina (Leming et al., 1996) After investigating 22 highway structures in North Carolina, it was concluded that

ten of them have experienced extensive damage and are likely to see more damage

due to ASR. The following conclusions were drawn (Leming et al. 1996):

1. The most serious problems related to ASR were associated with the use of schist,

gneiss, and phyllites as coarse aggregate. Phyllite was present in ASR damaged

structures and missing in structures without phyllite. As a result, “the presence of

phyllite should be considered likely to produce ASR.”

2. On the other hand, a number of structures containing schist and gneiss did not

undergo any damage. As a result, determining the reactivity of aggregates cannot

be accomplished by simply determining their mineralogical composition using

petrographic analysis.

3. Even though the use of low alkali cement can be helpful, it does not ensure a low

alkali content concrete in the field. Damage structures were characterized with

high alkali contents.

4. Aggregates from the same source may vary widely as far as reactivity depending

on the structure.

5. Damaged structures were characterized by having low air content, “lower than

normally desired.”

4.18.4 ASR in Virginia (Lane, 1994) Alkali-silica reaction has been a major cause of the deterioration of several

concrete structures in Virginia. A report, completed by Lane (1994), examined the

occurrence of the reaction in Virginia structures. Table 4.12 summarizes the findings

of the study. The following conclusions were suggested (Lane, 1994):

1. Virginia aggregates containing microcrystalline and strained quartz have been

associated with ASR damage in the field.

110

2. The use of C 227 is not effective for identifying the reactivity of these

aggregates.

3. Cements with alkali content exceeding 0.40% should be used with a mitigation

method such as the use of fly ash, slag, or silica fume.

Table 4.12: Investigated Aggregate Source, Field Performance, and C 227

Results (Lane, 1994)

Aggregate Source

Rock Type

Field Performance

C227 Expansion

C 1260 Expansion, % 5-

day8-

day11-day

14-day

28-day

C 1260 Classification

Augusta Dolomitic Limestone Undetermined 0.04 0.09 0.18 0.23 Reactive

Blacksburg Argillaceous Dolomite Good 0.03 0.05 0.07 0.09 Innocuous

Warrenton Diabase Good 0.03 0.05 0.08 0.13 0.36 Reactive

Fredricksburg Quartzose Sand Undetermined 0.02 0.05 0.06 0.09 0.2 Reactive

Fredricksburg Quartzose Gravel Undetermined 0.04 0.07 0.09 0.12 0.28 Reactive

Richmond Quartzose Sand

Alkali-silica reactive

0.045% @27 mon 0.03 0.06 0.13 0.19 0.37 Reactive

Richmond Quartzose Gravel

Alkali-silica reactive

0.016% @ 6 mon 0.13 0.21 0.27 0.32 0.49 Reactive

Rockville Hylas Metarhyolite Alkali-silica

reactive 0.014%

@ 6 mon 0.18 0.25 0.34 0.39 0.59 Reactive

Sylvatus Qartzite Undetermined 0.021% @ 6 mon 0.12 0.19 0.26 0.30 0.43 Reactive

Mt. Athos Acrch Marble Calc Chist

Alkali-silica reactive

0.012% @ 6 mon 0.03 0.08 0.12 0.17 0.30 Reactive

Shelton Granite Gneiss

Suspected Alkali-silica

reactive 0.05 0.09 0.13 0.17 0.28 Reactive

Red Hill Lovingston

Granite Gneiss

Alkali-silica reactive

0.049% @27 mon 0.03 0.04 0.06 0.07 0.14 Reactive

Shadwell Greenstone Metabasalt

Alkali-silica reactive

0.038% @27 mon 0.03 0.04 0.06 0.08 0.15 Reactive

Note: the C 1260 Classification was changed from the original data to represent the new findings for the test interpretation. Basically 14-day expansions higher than 0.08% are considered reactive.

111

4.18.5 ASR in South Dakota (polynomial and Avrami) To improve the interpretation of the C 1260 results, two models were introduced

by Johnston of the South Dakota DOT (1994). The first model consisted of using a

polynomial fit procedure on the C 1260 expansions versus time for each of the tested

aggregates and then to plot the coefficients of these curves against each other. This

process was more detailed in Johnston’s paper published in 1994. The advantage of

this model was that it considered the expansion history over the full 14-day period

instead of just using the 14-day expansion reading. According to the findings of

previous researchers, the polynomial fit procedure should show a clear separation

between innocuous and reactive aggregates with the innocuous aggregates being

concentrated around one line and reactive aggregates being concentrated along

another separate line (Johnston, 1994).

The second model consisted of applying Avrami’s equations to the C 1260

expansions. The model, presented in 1940, described the nucleation and growth

reaction using equation 4.5 (Johnston, 1994).

α = 1 + α0 − e (-k * (t-t0)^M) (Eq 4.5)

In that equation, α0 is the degree of expansion at time t0 representing the time at

which the nucleation and growth becomes dominant. In the case of C 1260, t0 is the

fourth day of curing. The constant k in equation 4.4 is a rate constant that reflects the

effects of nucleation, multidimensional growth, the geometry of reaction products,

and diffusion. The constant M is combining the effects of parameters P, Q, and S as

desribed in equation 4.6 (Johnston, 1994).

M = P/S + Q (Eq 4.6)

112

The parameter P describes the dimensionality of the product phase with P = 1, P =2,

and P = 3 respectively corresponding to needles, sheets, polygonal forms. S = 1

indicates a phase boundary growth while S = 2 indicates the diffusion of components

through the liquid phase. Q = 0 indicates no nucleation and Q = 1 indicates constant

nucleation. It is assumed that the characteristics of the alkali-silica reaction are (1)

sheet formation (P = 2), (2) diffusion through the liquid phase (S = 2), and (3) no

nucleation (Q = 0), which means that the value of M is almost 1 for ASR. Taking the

double natural log of both sides of equation 1 results in equation 4.7 (Johnston,

1994):

ln ln (1 / 1+α+α0) = ln (t-t0)*M + ln(k) or Y = X*M + ln (k)

Plotting X versus Y for each aggregate will result in an intercept value for ln(k)

and a slope value for M. The validity of this model for ASR kinetics was evaluated

by Johnston in his 1998 paper. He concluded that using the model allows the correct

prediction of an aggregate reactivity with ln(k) equals to -6 being the separating

value between reactive and innocuous aggregates. Aggregates with ln(k) greater than

-6 are reactive and aggregates with ln(k) less than -6 are innocuous. He also

concluded that the model is very efficient in evaluating and predicting the

effectiveness of mitigation methods (Johnston, 1994).

4.18.6 Mid-Atlantic Regional Technical Committee (Mid-Atlantic RTC, 1993)

In June of 1993, the Mid-Atlantic Regional Technical Committee published a

report titled “Guide Specifications for Concrete Subject to Alkali-Silica Reactions”.

Recommended practices are summarized in the following two Tables 4.13 and 4.14.

(Eq 4.7)

113

Table 4.13: Recommended Testing Procedures and Limits (Mid-Atlantic RTC, 1993)

Testing Procedures Description Limits

ASTM C 295 Petrographic Examination of Aggregates for Concrete

Optically strained, microfractured, or microcrystalline quartz (commonly found in granite and granite gneiss)

5.0 % (max.)

Chert or chalcedony 3.0 % (max.) Tridymite or cristobalite 1.0 % (max.) Opal 0.5 % (max.) Natural volcanic glass 3.0 % (max.)

ASTM C 1260 Average mortar expansion after 14-day of curing in 1M NaOH at 800C 0.10 % (max.)

ASTM C 227 Average mortar expansion after 6 months 0.10 % (max.)

Aggregates containing reactive materials as determined by ASTM C 295, should

be tested using C 1260. If the aggregate is still showing signs of reactivity, it should

be considered as potentially reactive unless additional testing results and service

records support its reclassification and are found to be acceptable to the specifier. C

227 might not be able to detect all reactive aggregates. However, aggregates that fail

the test should be considered as potentially reactive.

Table 4.14: Recommended Mitigation Alternatives and Methods of Validation (Mid-Atlantic RTC, 1993)

Mitigation Alternative Recommended Percentage

Validation Method

Class F fly ash 15 % (min.) C 227, C 1260 Class C fly ash 25 % (min.) C 227, C 1260 Slag 25 % (min.) C 227, C 1260 Silica fume 5 % (min.) C 227, C 1260

114

4.18.7 AASHTO ASR Lead State Team (Lead State Team, 1999)

In 1999, the AASHTO ASR Lead State Team published a report similar to the

Mid-Atlantic committee report. Major recommendations are summarized in Tables

4.15 and 4.16. One of the Lead State Team recommendations was to use the

procedures detailed in SHRP C-315, Handbook for the Identification of Alkali-Silica

Reactivity in Highway Structures, in order to determine whether a concrete structure

is affected by the alkali-reactivity of aggregates.

Table 4.15: Recommended Testing Procedures and Limits (Lead State Team, 1999)

Testing Procedures Description Limits

ASTM C 295 Petrographic Examination of Aggregates for Concrete

Optically strained, microfractured, or microcrystalline quartz

5.0 % (max.)

Chert or chalcedony 3.0 % (max.) Tridymite or cristobalite 1.0 % (max.) Opal 0.5 % (max.) Natural volcanic glass 3.0 % (max.)

AASHTO T 303 (ASTM C 1260) Accelearted Detection of Potentially Deleterious Expansion of Mortar Bars Due to Alkali-Silica Reaction

Mean mortar bar expansion at 14 days

0.08 % (max.) metamorphic aggregates 0.10 % (max.) all other aggregates

Perform a polynomial fit of data at 3, 7, 11, and 14 days to determine reliability of results

Repeat the AASHTO T 303 if r2 is less than 0.95.

ASTM C 1293 Concrete Aggregates by Determination of Length Change of Concrete Due to Alkali-Silica Reaction

Mean concrete prism expansion at 1 year 0.04 % (max.)

ASTM C 295 should be used as verification to either T 303 or C 1293. Using C

1293, some reactive aggregates might not develop expansions greater than 0.040%

after one year. However, these aggregates will result in extensive cracking of the

concrete prism surface.

115

Table 4.16: Recommended Mitigation Alternatives and Methods of Validation (Lead State Team, 1999)

Mitigation Alternative Recommended Percentage Validation Method Mineral Admixture Methods

Class F fly ash 15 % (min.) C 441, T 303, or C 1293 Class C fly ash 25 % (min.) C 441, T 303, or C 1293 Class N pozzolan Not specified C 441, T 303, or C 1293 GGBFS 25 % (min.) C 441, T 303, or C 1293 Silica fume 5 % (min.) C 441, T 303, or C 1293

Cement Methods Low alkali cement 100 % C 441 Blended Cement 100 % T 303 or C 1293

Chemical Admixture Methods LiNO3 Lithium Nitrate

Use 4.6 liters or 5.5 kilograms (min.) per kilogram of Na2Oeq

C 441 or C 1293

Deduct from the mix water an equivalent volume of 85% of the LiNO3 solution.

4.18.8 Portland Cement Association (Farny and Kosmatka 1997)

In 1997, the Portland Cement Association (PCA) published a report summarizing

the state-of-art of ASR (Farny and Kosmatka 1997). The flow chart shown in Figure

4.4 summarizes the recommendation for best testing procedures.

4.18.9 The National Aggregate Association (NAA, 1999)

The National Aggregate Association (NAA) investigated the effectiveness of

ASTM C 1260 and C 1293 using aggregate samples obtained from about 150 sources

representing different regions of the United States (154 aggregates were tested).

Results of aggregates that were tested with both C 1260 and C 1293 are included in

Table 4.17.

116

Figure 4.4: Flow Chart Suggested by PCA (Farny and Kosmatka 1997)

117

1. Results of C 1260 performed on fine and coarse aggregates from the same source

were not always comparable. In nearly two-third of the cases, the fine aggregates

showed higher expansions. This raises concern over the ability of C 1260 to

correctly evaluate the reactivity of coarse aggregates.

2. Eighty percent of the tested aggregates have been used in concrete for more than

10 years. Still, 73% of the aggregates showed 14-day expansions higher than

0.10% and 52% showed 14-day expansions higher than 0.20%

3. When comparing the results of C 1260 and C 1293 performed on the same

aggregates, it was observed that only two out of ten investigated aggregates were

classified as reactive using the two tests. The remaining eight aggregates were

classified as reactive when tested using C 1260 and non-reactive when tested

using C 1293.

4. Similarly, there was no correlation between the results of C 1260 and C 227.

Most aggregates classified as reactive with C 1260 were found to be non-reactive

with C 227.

5. Field service records reported by aggregate producers did not correlate with the

results of C 1260. Most aggregates classified as reactive did not cause deleterious

expansions in concrete.

6. When using C 1260, consideration should be given to the absorption of

aggregates in order to ensure a constant water-cement ratio.

7. Rejection of an aggregate for use in concrete should not be based solely on the

results of C 1260.

4.18.10 Lithium as A Preventive Measure

Recent work has been concentrated on determining the effects of lithium additives

on ASR. The use of lithium as an ASR mitigation alternative have been investigated

by several researchers including Stanton (1940), McCoy and Caldwell (1951),

Sakaguchi et al. (1989), Ong and Diamond (1993), Stark (1993), and Wang et al.

(1994). The mentioned and other researchers have shown that lithium can be used to

118

mitigate damage due to ASR. The effective dosages varied depending on the molar

ratio Li:Na and varied between 0.6 and 0.9. ASTM C 1260 was found to be not

effective in evaluating the usefulness of lithium mainly due to the lithium leaching

out of the mortar bars and into the curing solution. It was recommended by Starks to

add lithium to the curing solution at the same rate as that used for the mortar bars

(1993).

Table 4.17: C 1260 and C 1293 Results of Testing Performed by NAA (NAA, 1999)

lot CompF/C N/M Petro St

C126014-Day

% C 1260

Classification

C 1293 1-yr %

C 1293 Classification

004 2 C M LS OK 0.252 Reactive 0.083 Reactive 007 4 F N SI, DO WI 0.227 Reactive 0.009 Innocuous 008 4 C CG DO, SI WI 0.159 Slowly Reactive 0.020 Innocuous 017 9 F N LS ALB 0.285 Reactive 0.015 Innocuous 018 9 C CG LS ALB 0.335 Reactive 0.070 Reactive 023 12 C CG SI CO 1.061 Highly Reactive 0.196 Reactive 032 16 C M LS PA 0.041 Innocuous 0.016 Innocuous 043 21 F N SI NE 0.210 Reactive 0.012 Innocuous 049 22 F N SI CO 0.139 Slowly Reactive 0.018 Innocuous 052 23 F N SI SD 0.250 Reactive 0.012 Innocuous 055 25 F N SI CA 0.678 Highly Reactive 0.026 Innocuous 060 26 C N SI NV 1.072 Highly Reactive 0.016 Innocuous 064 28 F N SI CA 0.080 Innocuous 0.008 Innocuous 088 37 C CG DO, LS, SI NY 0.154 Slowly Reactive 0.038 Innocuous 129 48 F N SI IN 0.279 Reactive 0.007 Innocuous 139 49 F N SI MI 0.316 Reactive 0.005 Innocuous

Type: F = Fine agg., C = coarse agg. N/M: N = Natural, M = Manufactured, CG = Crushed Gravel Petro: SI = Siliceous, LS = Limestone, DO = Dolomite, U = Unknown

During the Strategic Highway Research Program, a field test was initiated to

investigate the effectiveness of lithium hydroxide monohydrate in several pavement

119

sections in Albuquerque, NM (Starks 1993). Reactive aggregates were used in the

pavements in combination with a cement having 0.55% alkali content. Long-term

monitoring of the pavement is an ongoing process.

4.19 ASR IN DENMARK (Chatterjee et al. 1992)

Most of the aggregate sources available in Denmark contain some form of

reactive components. “There is always a risk of ASR (Chatterjee et al. 1992).” As a

result, Denmark is very active and very strict in providing specifications for

preventing ASR damage in concrete. The following is a description of the practices

used to address ASR:

There are three parameters used to minimize the risk of ASR in concrete:

1. Alkali content of the concrete

2. Reactivity of the aggregate

3. Environmental conditions

4.19.1 Alkali Content of the Concrete

The alkali content of the cement is added to alkalis from other sources such as

mineral and chemical admixtures used as mixture components to determine under

which group the cement falls. Table 4.18 includes the different cement groups. “The

assumption of a constant and uniform distribution of alkali in a concrete structure has

been dropped” (Chatterji et al. 1992).

Table 4.18: Alkali Content Groups (Chatterji et al. 1992) Group Label Description Details

EA Extra low Alkali ≤ 0.4% Na2Oeq. LA Low Alkali ≤ 0.6% Na2Oeq. MA Medium Alkali ≤ 0.8% Na2Oeq. HA High Alkali ≤ 0.4% Na2Oeq.

120

4.19.2 Environmental Classification

Three environmental classes are defined as follows:

1. Aggressive Environmental Class: Includes concrete exposed to salt, flue gases,

seawater, or brackish water.

2. Moderate Environmental Class: Includes concrete exposed to moisture, non-

aggressive outdoor and indoor environment, and flowing or standing fresh water.

3. Passive Environmental Class: Includes concrete exposed to dry and non-

aggressive environment (particularly indoor climate).

4.19.3 Aggregate Specification

Aggregates are classified into three different categories:

1. Class P: Used in passive environments

2. Class M: Used in moderate environments

3. Class A: Used in aggressive environments

Sands are classified using thin-section point-count method or the mortar bar

expansion test in saturated sodium chloride solution. Example of such a classification

is included in Table 4.19.

Table 4.19: Sand Classification (Chatterji et al. 1992) Class P Class M Class A

Volume of reactive Flint (%) No Demand Max. 2.00% Max. 2.00% Mortar bar expansion at 8 weeks No Demand Max 0.10% Max. 0.10%

Coarse aggregates are limited by their content of reactive components and the

absorption of the flint with density larger than 2400 kg/m3. Table 4.20 is an example.

Table 4.20: Coarse Aggregate Classification (Chatterji et al. 1992) Class P Class M Class A

Particles with density less than 2400 kg/m3 No Demand Max. 5.0% Max. 1.0% Absorption No Demand Max. 2.5% Max. 1.1%

121

4.19.4 Concrete Specifications

The Danish code of practice called “BBB (Basis Betonbeskrivelsen for

Byningskonstruktioner)” requires that concrete used in all public building

construction should be proportioned as a function of all the above factors and as

detailed in Table 4.21.

Table 4.21: Specifications for Concrete (Chatterji et al. 1992)

122

4.20 FINAL REMARKS

After reviewing the literature and examining how different countries manage the

alkali-silica reactivity of aggregates, it was clear that there is a lack of unified

procedures and guidelines. Different countries have adopted different aggregate

testing procedures and different ASR mitigation measures that best fit their needs. It

was noticed that there is a great interest in reliable accelerated testing procedures

capable of predicting the potential reactivity of aggregates in a short period of time.

It also seemed that ASTM C 1260, ASTM C 1293, and modifications or

combinations of these procedures are becoming more and more popular and more

trusted in giving accurate results. Some guidelines are available to manage the alkali-

silica reactivity of aggregates.

123

CHAPTER FIVE

TESTING MATERIALS

5.1 AGGREGATE SELECTION

After reviewing the literature and contacting knowledgeable researchers and

industry representatives, a list of 200 aggregates was compiled from which the

selection was made for the testing program. The aggregates possessed different

physical and chemical properties, represented different regions of the USA, had

different field performances as far as ASR performance, and had different laboratory

performances when tested for ASR.

Aggregates for the testing program were acquired from fourteen different

aggregate producers providing a total of twenty-three aggregates of which ten were

coarse, twelve were fine, and one was mixed sand and gravel.

Aggregates were selected to cover the complete spectrum of ASR reactivity as

shown in Table 5.1. Aggregates were also representative of most regions of the USA

as shown in Figure 5.1. Table 5.2 contains a list of all chosen aggregates including

their types and sources.

Table 5.1: Aggregates Representing the Complete Spectrum of ASR Reactivity

Category Field Performance Laboratory Performance A Poor Reactive B Poor Inconclusive C Poor Non-Reactive D Good Non-Reactive E Good Reactive

124

Figure 5.1: Locations of the Selected Aggregate Sources

= NAA Aggregates

Aggregates Tested at

125

Table 5.2: Aggregates and Aggregate Sources Selected for the Study

Agg. Number

Aggregate I.D.

Agg. type

Aggregate Mineralogy

Aggregate Source

Category A: Poor field performance / tested reactive 1 A1-WY Coarse Rhyolite Wyoming 2 A2-WY Fine Rhyolite Wyoming

3 A3-ID Coarse Quartzite, sandstone, limestone, andesite, rhyolite Idaho

4 A4-ID Fine Quartzite, sandstone, limestone, andesite, rhyolite Idaho

5 A5-NM (PL) Coarse Rhyolite, andesite New Mexico 6 A6-NM (PL) Fine Rhyolite, andesite New Mexico 7 A7-NC Coarse Argillite N. Carolina

8 A8-VA Coarse Quartz, quartzite, granitic rock fragments, siltstone, sandstone, and natural mineral fragments

Virginia

9 A9-NE Mixed Pink granite, orthoquartzite, metaquartzite, chert, metachert and allogenic quartz

Nebraska

10 A10-PA Fine Pennsylvania Category B: Poor field performance / tested inconclusive

11 B1-MD Coarse Chlorite feldspar, quartz, and chlorite Maryland

12 B2-MD Fine Chlorite feldspar, quartz, and chlorite Maryland

13 B4-VA Fine Quartz, quartzite, granitic rock fragments, siltstone, sandstone, and natural mineral fragments

Virginia

Category C: Poor field performance / tested nonreactive (slow reactive)

14 C1-SD Coarse Pink quartzite, pyroxene, iron oxide, sericite, Clay South Dakota

15 C2-SD Fine Pink quartzite, pyroxene, iron oxide, sericite, Clay South Dakota

Category D: Good field performance / Tested nonreactive 16 D1-IL Coarse Dolomite Illinois 17 D2-IL Fine Dolomite Illinois

Category E: Good field performance / tested reactive 18 E2-Ia Fine Glacial deposit, shale Iowa 19 E3-NV Coarse Natural siliceous and glassy Nevada 20 E4-NV Fine Natural siliceous and glassy Nevada 21 E6-IN Fine Natural siliceous Indiana 22 E7-NM (SA) Coarse Rhyolite, andesite New Mexico 23 E8-NM (SA) Fine Rhyolite, andesite New Mexico

126

Identifications for each aggregate tested, as specified in Table 5.2, were used

throughout the study to identify the aggregate source. The first letter indicates the

category to which the aggregate belongs. The next number indicates the number of

that aggregate in its specified category. An odd number indicates a coarse aggregate

while an even number indicates a fine aggregate. The next two letters indicate the

state from which the aggregate was sent. For example, A1-WY is a category A

coarse aggregate from Wyoming and E4-NV is a Category E fine aggregate from

Nevada. Detailed information about the history of Table 5.2 aggregates, their field

performance, and petrographic analysis can be found in Appendix D.

Field and laboratory performance of aggregates (Table 5.2) was determined using

information provided by aggregate producers and DOTs that have extensively used

these aggregates in field applications. Information provided was summarized in

Appendix D where the history of all the aggregates is detailed.

5.2 OTHER TESTING MATERIALS

Two types of cements with an average alkali content of 0.60 and 1.14% were used

throughout the study. Admixtures included one class F fly ash, one class C fly ash,

silica fume, granulated slag, calcined clay, lithium nitrate, one high range water

reducer, and one air entraining agent. Physical and chemical properties are provided

in Tables 5.3 through 5.9.

127

Table 5.3: Chemical and Physical Properties of Type I/II Cement with High Alkali Content

Chemical Composition Physical Properties Metal Oxide Specific Surface

Element Percent Blaine 3910 cm2/g SiO2 20.90 Al2O3 4.43 Fe2O3 3.01 CaO 62.65 Soundness MgO 2.97 Autoclave Expansion 0.88 SO3 3.06 Le Chatelier’s 2

Alkali Oxide Na2O 0.35 K2O 1.21

Na2Oequiv 1.14 Set Time (min.) Phase Analysis Gilmore Vicat

C3S 53.5 Initial Set 175 80 C2S 19.6 Final Set 300 225 C3A 6.6

C4AF 9.2 Air Content

Loss of Ignition 1.68 % H20 66.2 Insoluble Residue 0.51 % Flow 84

Free Lime 1.15 % Air 8.0

128

Table 5.4: Chemical and Physical Properties of Type I/II Cement with Low Alkali Content

Chemical Composition Physical Properties Element Percent Specific Surface

Silicon Dioxide 21.30 Blaine (cm2/gm) 3530 Aluminum Dioxide 4.60 Wagner (cm2/gm) 1970 Ferric Oxide 4.10 Calcium Oxide 64.60 Magnesium Oxide 0.90 Compressive Strength Sulfur Trioxide 2.60 1-Day 2190 Loss on Ignition 1.10 3-Day 3650 Insoluble Residue 0.20 7-Day 4670 Free Lime 0.70 Tricalcium Silicate 57.00 Tricalcium Aluminate 5.20 Set Time Na2Oequiv. 0.50 Vicat Gilmore Initial Set (min.) 100 130 Final Set (min.) 210 230

Table 5.5: Chemical Properties of Granualted Slag Element Percent

SiO2 38 Al2O3 8 Fe2O3 Tr. CaO 42 MgO 7 SO3 ----

S 1 Na2Oequiv 0.4

MnO 1

129

Table 5.6: Chemical and Physical Properties of Calcined Clay Chemical Composition Physical Properties

Metal Oxide Specific Surface Element Percent Blaine ----

SiO2 52.45 Al2O3 16.91 Fe2O3 9.04 CaO 11.70 Soundness MgO 1.70 Autoclave Expansion -0.02** SO3 3.06 45 Micron, passing 95.1 %

Alkali Oxide Na2O 0.24 K2O 2.32

Na2Oequiv 1.76 Set Time (Hrs:Min) Compressive Strength, psi Gilmore Vicat

1 Day Initial Set --- 3:25** 3 Day 2950** Final Set --- 5:25** 7 Day 4110**

Air Content

Loss on Ignition 1.70 % H20 ---- Specific Gravity 2.40±0.05 % Flow ----

Normal Consistency 27.7%** % Air ---- **Indicates these tests were done using 20% replacement of cement

130

Table 5.7 Chemical and Physical Properties of the Class C Fly Ash Chemical Composition Physical Properties

Metal Oxide Element Percent

SiO2 34.99 Specific Gravity 2.63 Al2O3 20.25 Fe2O3 6.24 Retained on #325 16.57 % CaO 26.12 MgO 4.65 Water Requirement 94 % SO3 1.74

Autoclave Exp. 0.09 % Total Alkali

Na2Oequiv 1.18

Loss on Ignition 0.28 Moisture Content 0.06

Table 5.8 Chemical and Physical Properties of the Class F Fly Ash Chemical Composition Physical Properties

Metal Oxide Element Percent

SiO2 56.5 Specific Gravity 2.40 Al2O3 19.3 Fe2O3 4.7 Retained on #325 22.5 % CaO 12.3 MgO 2.3 Water Requirement 94.2% SO3 1.5

Autoclave Exp. 0.02% Total Alkali

Na2Oequiv 0.3

Loss on Ignition 0.3 Moisture Content 0.1

131

Table 5.9: Properties of Chemical Admixtures

Admixture Type Description

Conforms to

Air-Entrainment

Is a light-orange liquid product based on a high-grade saponified rosin formulation. It is chemically similar to vinsol-based products but with increased purity. Typical addition rates range from 50 to 200 mL/100 kg (3/4 to 3 fl oz/100 lbs) of cement to have 4 to 8% air.

ASTM C 260

Super-plasticizer

Is a high range water-reducing admixture that contains no added chloride. 1 liter weighs approximately 1.08 kg (9 lb/gal). It is a dispersing admixture having a capacity to disperse the cement agglomerates. Typical addition rates range from 195 to 650 mL/100 kg (3 to 10 fl oz/100 lb) of cement.

ASTM C 494

Type F

Lithium Nitrate Is a solution of LiNO3 diluted with water.

132

CHAPTER SIX

LABORATORY TESTING PROCEDURES

6.1 INTRODUCTION

The laboratory testing-program was divided into three stages:

1. Stage 1 consisted of testing each aggregate to determine the physical properties

required for concrete proportioning. Aggregates were also prepared for mortar

and concrete batching.

2. Stage 2 consisted of testing all aggregates listed in Table 5.2 using ASTM C 227,

C 1260, and C 1293. Modifications to these tests were also investigated during

this stage.

3. Stage 3 consisted of investigating ASR mitigation alternatives.

6.2 STAGE 1: AGGREGATE TESTING AND PREPARATION

Aggregate testing was divided into two phases: 1) fine aggregate testing and 2)

coarse aggregate testing. Table 6.1 shows a list of all aggregate tests performed on

both fine and coarse aggregates.

Table 6.1: Aggregate Testing Performed

Aggregate Test Fine Coarse ASTM C 29 : “Unit Weight and Voids in Aggregate” ASTM C 127:“Specific Gravity and Absorption of Coarse Aggregate” ASTM C 128: “Specific Gravity and Absorption of Fine Aggregate” ASTM C 136: “Sieve Analysis of Fine and Coarse Aggregates”

= Test performed for this aggregate type

ASTM C 227 and C 1260 require that all aggregates be graded as per Table 6.2.

As a result, all aggregates had to be separated into the required sieve sizes, washed

over a #100 sieve, and then combined using the specified quantities for each sieve.

ASTM C 1293 requires that the coarse aggregate be proportioned as described in

133

Table 6.3. Again all coarse aggregates were sieved and aggregate portions retained

on the specified sieves were separated into different containers. Before concrete

batching, the different sizes were combined in accordance with the requirements of

Table 6.3. Fine aggregates to be tested according to C 1293 did not require any

processing and were tested as supplied. Figures 6.1 and 6.2 illustrate the aggregate

preparation procedures.

Table 6.2: ASTM C 227 and C1260 Aggregate Grading Requirements

Sieve Size Passing Retained on Mass, %

4.75 mm (No. 4) 2.36 mm (No. 8) 10 2.36 mm (No. 8) 1.18 mm (No. 16) 25 1.18 mm (No. 16) 600 µm (No. 30) 25 600 µm (No. 30) 300 µm (No. 50) 25 300 µm (No. 50) 150 µm (No. 100) 15

Table 6.3: ASTM C 1293 Coarse Aggregate Grading Requirements

Sieve Size Passing Retained on Mass, %

19 mm (3/4-in) 12.5 mm (1/2-in) 33 12.5 mm (1/2-in) 9.5 mm (3/8-in) 33 9.5 mm (3/8-in) 4.75 mm (No. 4) 33

134

Figure 6.1: Aggregate Washing Over #100 Sieve

Figure 6.2: Sieve Sizes Required For C 227 and C 1260 Mortar Bars

135

6.3 STAGE 2: TESTING FOR THE POTENTIAL ALKALI-SILICA

REACTIVITY OF AGGREGATES

6.3.1 Aggregate Testing Using ASTM C 227

All the fine aggregates listed in Table 5.2 were sieved, washed over a #100 sieve,

and combined in accordance with Table 6.2 to cast 1-in. x 1-in. x 11-in. mortar bars.

A total of two bars per aggregate were made. A fixed water-cement ratio of 0.47 was

used for all the mixtures instead of the range of flow numbers (flow between 105 and

120) specified by the actual testing procedures. The flow of all mixtures was

determined in accordance with the procedures detailed in ASTM C 109,

“Compressive Strength of Hydraulic Cement Mortars,” and the unit and air content

in accordance with the requirements of ASTM C 138, “Weight per Cubic Foot, Yield,

and Air Content of Concrete”. After fabrication, the bars were stored for 24 hours,

while still in the forms, in a moisture room. All bars were then demolded and stored

in sealed containers over water in an environmental room at 100oF. Absorbent

material around the walls of the containers was not used. Expansion data were

recorded after 14 days of curing and then every 1, 2, 3, 4, 6, 9, and 12 months.

Aggregate-cement combinations showing 3-month expansions higher than 0.05% or

6-month expansions higher than 0.10% were considered ASR reactive. Aggregate-

cement combinations showing 3-month expansions higher than 0.05% but 6-month

expansions lower than 0.10% were considered innocuous. Procedures for this test are

summarized in Figures 6.5 and 6.6. Figures 6.3 and 6.4 show some of the mortar bar

mixing procedures.

6.3.2 Aggregate Testing Using ASTM C 1260

In a similar manner to the C 227 procedures, aggregates were also used to cast 1-

in. x 1-in. x 11-in. mortar bars. Three mortar bars were cast using each of the

aggregates. All mixtures were also tested for flow, unit weight, and air content in

accordance with the requirements of ASTM C 109 and C 138 respectively. After 24

136

hours of moist curing, bars were stored in water at 80oC for 24 hours after which the

initial readings were recorded. Subsequent measures consisted of storing the bars in

a 1N NaOH solution at 80oC and recording expansion readings at 4, 7, 11, 14, 21,

and 28 days. A 14-day expansion greater than 0.20% indicated a potentially reactive

aggregate in the field, while a 14-day expansion smaller than 0.10% indicated a non-

recative (innocuous) aggregate. Recent specifications have mentioned that 14-day

expansions higher than 0.10% should be used to classify aggregates as reactive.

Figures 6.7 and 6.8 show the curing process while Figure 6.9 includes a summary of

the C 1260 procedures.

Figure 6.3: Mortar bars cured for 24 hours in a moisture room, immediately after being formed (C 227 and C 1260)

Figure 6.4: Mortar bars stored over water, in containers with no wicks, in an environmental room at 380C

Figure 6.5: First Step in Performing ASTM C 227

Either Use Emmediately orStore in Jars for Later Use

Weight 330-g of Cement

Pass Cement Through a No.20 Sieve

Select Cement Type

Cement Handling

Put Excess Materials in a Plastic Bagand Store it with the Original Aggregate

Move Weighted Sample to 70-deg Rm24-hrs Before Mixing

Weight 675-g Sample,Label, and Store

Sieve for 5-min. in 300-g incrementsStop Sieving When Required Amount

is Obtained

Oven Dry

Wash Over #100 Sieve

Mix Fine AggregateSample 2000g w/Sampling Tube

No Project RequirementsSands Satisfy Table 1

Remove Materials Retained onNo.4 Sieve

Mix Fine AggregateSample 2000g w/Sampling Tube

Required Project Grading

Fine Aggregate

Wash Aggregate While on Sieve

Wash Over #100 Sieve

Sample Approximately 10-lbswith Sample Splitter

Crushed Coarse Aggregate Satisfying Table 1 Requirements

Choose Aggregate and Assign Number

Aggregate Handling

137

Figure 6.6: Second Step in Performing ASTM C 227

(See Proportioning

Directions)

(See Mixing and Molding

Procedures)

Not needed when duplicate

mortar is made for additional

specimens

Return Containers to 100-Deg

Room

Take Readings at

1,2,3,4,6,9, and 12-MonthsExamine Specimens

Day 0Day 1

Day 2

Day 14

Day 151-year

(1) Strip Molds(2) Label Bars

Take 14-Day ReadingsClean Container, Change Water

Return Specimens in Inverted Position

Take Containers Out and Place

for at Least 16-Hrs at 73.4-Deg

Place Specimens in Containers

in 100-Deg. Envir. for 12-Days

(3) Record Initial Reading(4) Clean Molds and Assemble

Place Specimens in Moisture Rm for 24 hrs

Fill the Molds, 2-Min 15-s

Run Flow Test and Return Materials to

Mixing Bowl, Mix for 15-s

Mix the Mortar

Assemble Molds, Oil with Agent

and Set Gage Studs

Set Up Data Books

and Schedule Readings

Proportion Dry Materials

138

139

Several research programs and papers in the literature have documented the

effectiveness of C 1260 for predicting the potential alkali-reactivity of aggregates

and for investigating the effectiveness of mitigation alternatives such as the use of air

entrainment, mineral admixtures, pozzolans, and chemical admixtures. In general,

most of the researchers and users agreed that this test is a good ASR predicter;

however, it is too severe for some aggregates that have had good field performances

(Category E aggregates). To overcome this obstacle, several modifications of the C

1260 were investigated including:

1. Using different interpretation methods: Avrami’s model and the polynomial fit

procedures, both of which were discussed earlier.

2. Changing the molarity of the curing solution: 0.75N, 0.50N, and 0.25N.

3. Expanding the length of testing from 14 days to 56 days.

4. Changing the water content of the mixing proportions so as to account for the

absorption of the tested aggregate. The water-cement ratio is controlled at 0.47.

This modification was not used to remedy the Category E problem but to

improve the consistency of the mixing procedures.

140

Figure 6.7: Mortar bars stored in a 1N NaOH solution used for C 1260

Figure 6.8: Mortar bars stored in an oven at 800C, in 1N NaOH solutions (C 1260 requirements)

Figure 6.9: ASTM C 1260 Procedures

(See ProportioningDirections)

(See Mixing and MoldingProcedures)

Take 4-Day Readings Take 7-Day Readings Take 11-Day Readings Take 14-Day Readings

Clean Molds and Assemble

Day 0

Day 1

Day 2Day 3Day 7 Day 10 Day 14 Day 17

Strip Molds Label Bars

Place Specimens in NaOH Solutionin 176-Deg. Envir.

Remove Containers One at aTime and Take Zero Readings

Place Specimens in H20in 176-Deg. Envir. for 24-Hrs

Prepare the NaOH Solutionand STore in Comtainers at 176-deg

Record Initial Reading

Place Specimens in Moisture Rm for 24 hrs

Mix Mortarand Prepare Bar Specimens

Assemble Molds, Oil with Agentand Set Gage Studs

Set Up Data Booksand Schedule Readings

Proportion Dry Materials

141

142

6.3.3 Aggregate Testing Using ASTM C 1293

Aggregates listed in Table 5.2, including fine and coarse aggregates, were used to

cast 3-in. x 3-in. x 11-in. concrete prisms in accordance with the requirements of

ASTM C1293. All mixtures were batched using the procedures described in ASTM

C 192, “Making and Curing Concrete Test Specimens in the Laboratory,” tested for

the slump according to ASTM C 143, “Slump of Portland Cement Concrete”, and

tested for the unit weight and air content as described in ASTM C 138. Prisms were

covered with a plastic sheet and stored in a moisture room immediately after

fabrication. After 24 hours of curing, prisms were demolded and subjected to the

following testing conditions:

1. Over water, in a sealed 6-gal bucket with absorbent material covering the sides,

and in an environmental room at 38oC (3 prisms/container). These are the

requirements of C 1293. The failure criterion for this test is 0.040% after 0ne

year of testing.

2. Over water, in a sealed 6-gal bucket with absorbent material covering the sides,

and in an environmental room at 60oC. The proposed failure criterion for these

procedures is 0.040% after 3 months of testing. This criterion was obtained from

the literature and will be discussed in Chapter 10.

3. In a 1N NaOH solution at 38oC. 2.2-liter containers were used (2

prisms/container). This is a proposed modification process that will result in

accelerated ASR results. The proposed failure criterion for these procedures is

0.040% after 26 weeks (6 months) of testing. This criterion was obtained from

the literature and will be discussed in Chapter 10.

4. In a 1N NaOH solution at 80oC. 2.2-liter containers were used (2

prisms/container). This is a modification that will result in yet more accelerated

results. The proposed failure criterion for these procedures is 0.040% after 4

143

weeks of testing. This criterion was obtained from the literature and will be

discussed in Chapter 10.

The initial readings were taken immediately after demolding, and readings were

recorded after 1, 2, 4, 6, 8, 13, 26, 39, and 52 weeks of curing. The estimated length

of C 1293 is one year. As a result, readings for prisms under the different conditions

continued for one year. Figures 6.10 through 6.13 illustrate several of the steps in

ASTM C 1293. Figures 6.14 and 6.15 contain a summary of the C 1293 procedures

that are common to all modifications. The only difference were the storage

environment.

Figure 6.10: Concrete prisms stored over water, in 6-gal buckets with wicks, in an environmental room at 380C

144

Figure 6.11: C 1293 buckets stored for 16 hours in a moisture room before measuring scheduled expansion readings

Figure 6.12: Top view of a C 1293 bucket; Concrete prisms over water;

Wicks on the sides; Seal cover

Figure 6.13: Concrete prism being measured for expansion

Figure 6.14: Aggregate Preparation for C 1293

Dry the Sand and Either Store or Test

Batch Sized Quantities Required forMixing

Blend the Material With the Sand

Remove Required Sand Fraction toProvide FM = 2.70 (from a portion)

Run, Specific Gravity, Absorption,Sieve Analysis, and Void Content

Sample Aggregate in DampCondition

Non-Reactive Fine Aggregate

Sample Quantities for Mixing fromthe Damp Sand not the Tetsed.

Oven DryStore

Run a Void Content Test by Recombiningthe Sieve Analysis Sample in the

Standard Grading

Use 500-g for a Sieve Analysis andPassing No.200

Determine Absorption andSpecific Gravity

Split the Sample and Obtain1000-g

Sample 2000g w/Sampling Tubeand Oven Dry

Fine Aggregate to Be Evaluated

Obtain Mixing Quantities From theDRUW Sample

Determine Specific Gravity andAbsorption

Split the Sample to Obtain 3000-g

Determine DRUWUsing a 0.2 cu.ft. Container

Sample About 30-lbRecombine According to Table 1

Wash Sample over No.4 SieveOven Dry

Coarse Aggregate to be Evaluated

Recombine Size Fractions inQuantities Used for Test

Determine Dry-Rodded Unit Weight (1/2 cu.ft. bucket)

Separate Aggreagte Into Table 1 Sizes

Determine Specific Gravityand Absorption

Non-Reactive Coarse Aggregate

Aggregate Handling

145

Figure 6.15: C 1293 Concrete Prism Procedures

(See ProportioningDirections)

(See Mixing and MoldingProcedures)

Not needed when duplicatemortar is made for additionalspecimens

Return Containers to 100-DegRoom

Take 28, 56-Day Readingsand 3,6,9,12-Months.

Examine Specimens

Day 0

Day 1

Day 2

Day 7Day 8 1-year

(1) Strip Molds (2) Label Bars

Take 7-Day Readings Clean Container, Change WaterReturn Specimens in Inverted Position

Take Containers Out and Placefor at Least 16-Hrs at 73.4-Deg

Place Specimens in Containersin 100.4-Deg. Envir. for 6-Days

(3) Record Initial Reading (4) Clean Molds and Assemble

Place Specimens in Moisture Rm for 24 hrs

Fill the Molds

Run Slump, Yield, and Air Content TestsReturn Concrete to Mixer

Mix the Mortar

Assemble Molds, Oil with Agentand Set Gage Studs

Set Up Data Booksand Schedule Readings

Proportion Dry Materials

146

147

6.4 STAGE 3: ASR MITIGATION ALTERNATIVES

ASTM C 1260 and C 1293 were used to evaluate the effects of Class C fly ash,

Class F fly ash, silica fume, granulated slag, calcined clay, lithium nitrate (LiNO3),

air content, and permeability on the ASR reactivity of selective aggregates. C 1293

was used to evaluate three aggregates of which one was highly reactive, one was

moderately reactive, and one was slowly reactive. Due to the short period of time

over which C 1260 can be conducted, six aggregates were chosen to evaluate the

mitigation alternatives using the test. The same aggregates used with C 1293 were

used with C 1260 with the addition of one highly reactive aggregate, one slowly

reactive aggregate, and one aggregate from Group E (Table 5.2). These aggregates

were chosen after the first run of C 1260 was completed, and the aggregates were

classified between highly reactive and innocuous according to their 14-day

expansions. Table 6.4 summarizes the aggregates investigated and tests

combinations.

All the concrete mixtures representing the mitigation alternatives mentioned in

Table 6.4 were tested for compressive strength as described in ASTM C 39,

“Compressive Strength of Cylindrical Concrete Specimens,” the modulus of

elasticity in accordance with ASTM C 469, “Static Modulus of Elasticity and

Poisson’s Ratio of Concrete in Compression,” the splitting tensile strength as

detailed in ASTM C 496, “Splitting Tensile Strength of Cylindrical Concrete

Specimens,” and the rapid chloride permeability according to ASTM C 1202, “Rapid

Chloride Ion Penetration Test.” These properties were needed to determine how the

mitigating alternatives are affecting the mixtures and to be able to determine whether

a decrease in aggregates reactivity is due to the method being investigated or due to

the decrease in permeability or any other property.

148

Table 6.4: Aggregates and Test Combinations Used to Investigate Mitigation Alternatives

ASTM C 1260 ASTM C 1293 Agg. # 6: A6-NM (Highly Reactive) Agg. # 4: A4-ID (Highly Reactive) Agg. # 2: A2-WY (Moderately Reactive) Agg. # 12: B4-VA (Slowly Reactive) Agg. # 14: C2-SD (Slowly Reactive) Agg. # 22: E2-IA

Note: Refer to Table 5.2 for aggregate notation and source locations = Aggregate evaluated using this test

6.5 SUMMARY OF THE TESTING PROGRAM

A summary of the testing program is included in Table 6.5 that includes standard

tests, modifications, and mitigation alternatives investigated.

149

Table 6.5: Summary of the Testing Program Tests investigated Mitigation Alternatives (C 1260, C 1293)

ASTM C 227 (Modified) - No Wicks - Fixed W/C = 0.47 - High alkali cement (≈ 1.25%Na2Oe) - Estimated length: 1-yr

Effect of Class C Fly Ash - 20%, 27.5%, 35% replacement by weight of cement

ASTM C 1260 (Standard) - Mortar 1N NaOH @ 800C - 14-day expansion

Effect of Class F Fly Ash - 15%, 25% replacement by weight of cement

ASTM C 1260M1 (Modified) - Mortar 1N NaOH @ 800C

- 14-day expansion - 0.25N, 0.5N, 0.75N NaOH @ 800C

Effect of Silica Fume - 5%, 10% replacement by weight of cement

ASTM C 1260M2 (Modified) - Mortar 1N NaOH @ 800C - 14-day, 28-day, 56-day expansion

Effect of Granulated Slag - 25%, 50%, 70% replacement by weight of cement

ASTM C 1260M3 (Modified) - Mortar 1N NaOH @ 800C - 14-day expansion - Avrami’s Model

Effect of Calcined Clay - 17%, 25% replacement by weight of cement

ASTM C 1260M4 (Modified) - Mortar 1N NaOH @ 800C - 14-day expansion - Polynomial Fit Procedures

Effect of Lithium Nitrate - 3.5L, 4.5L, 10L per 1-kg of Na2Oeq

ASTM C 1260M5 (Modified) - Mortar 1N NaOH @ 800C - 14-day expansion - W/C = 0.47 counting for absorption of Aggregates

Effect of Permeability by changing W/C (Fixed cement content and increasing water)

- W/C = 0.35, 0.55, 0.65

ASTM C 1293 (Standard) - Prisms Over Water @ 380C - Estimated length: 1-yr

Effectiveness of the above alternatives with different alkali content of mortar bars - C 1260M1; 0.5N and 0.75N

ASTM C 1293M1 (Modified) - Prisms Over Water @ 600C - Estimated length: 3 to 6 months

Low alkali mortar and concrete - C 1260M1; 0.25N, 0.5N, 0.75N - C 1293M1; 0.5%, 0.75%, 1.25% Na2Oe

ASTM C 1293M2 (Modified) - Prisms in 1N NaOH @ 380C - Estimated length: 6-months

ASTM C 1293M3 (Modified) - Prisms in 1N NaOH @ 800C - Estimated length: 8-weeks

150

CHAPTER SEVEN

MIXTURE PROPORTIONS

7.1 ASTM C 227 MIXTURE PROPORTIONS

ASTM C 227 was used to evaluate the aggregates listed in Table 5.2 for their

potential alkali-silica reactivity. A water-cement ratio by weight of 0.47 was used for

all mixtures. The absorption capacity of the aggregates tested (before sieve

separation) was considered in the calculation of the water demand. Table 7.1

includes a description of the mixtures investigated.

Table 7.1: Proportions and Mortar Properties for C 227 Mixtures

Agg. ID

Mixing Date

Cement g

(Note 2)

Agg. Dry

Weightg

(Note 2)

Water g

(Note 2) Flow

(Note 3)

Unit Weight kg/m3

(lb/ft3) (Note 4)

Air Content,

% (Note 4)

A1-WY 3/10/99 740 1665 361 64.5 2184 (136.3) 2.86 A2-WY 2/3/99 740 1665 361 115.0 2194 (137.0) 2.29 A4-ID 2/4/99 740 1665 380 108.5 2142 (133.8) 2.78

A6-NM 2/5/99 740 1665 376 109.5 2175 (135.8) 1.18 A7-NC 2/6/99 740 1665 357 41.5 2258 (141.0) 2.67 A9-NE 1/27/99 740 1665 353 116.5 2211 (138.0) 1.75 B2-MD 1/28/99 740 1665 361 69.0 2205 (137.7) 1.79 B4-VA 3/10/99 740 1665 348 87.0 2184 (136.3) 2.52 C2-SD 1/27/99 740 1665 353 83.5 2205 (137.7) 2.38 D2-IL 1/28/99 740 1665 378 106.0 2202 (137.5) 2.18 E2-IA 2/1/99 740 1665 366 97.0 2182 (136.2) 2.70 E4-NV 2/2/99 740 1665 443 81.0 1988 (124.1) 1.63 E6-IN 2/3/99 740 1665 366 113.0 2216 (138.3) 1.38

E8-NM 2/4/99 740 1665 370 98.0 2200 (137.3) 1.18 Note 1: Refer to Table 5.2 for Nomenclature Note 2: Weights were calculated on a 5-bars basis

Note 3: ASTM C 109 used to measure the Flow Note 4: ASTM C 138 used to measure the Unit Weight and Air Content

151

7.2 ASTM C 1260 MIXTURE PROPORTIONS

As mentioned earlier, this test was used to investigate its validity in predicting the

alkali-silica reactivity of aggregates in concrete and to investigate potential ASR

mitigation alternatives. Aggregates listed in Table 5.2 were tested using the C 1260

method and mixture proportions are included in this section. Mixture proportions for

the completed procedures are shown in Tables 7.2 through 7.11. In the following list

of tables, ASTM C 138 was used to measure the unit weight, yield, and air content

and ASTM C 109 was used to measure the flow. The unit weight is represented by

the Greek symbol γ and the water-to-cementitious materials ratio by W/CM. All

weights shown were calculated on a three-mortar bars basis.

Table 7.2: Mortar Mixtures Used for ASTM C 1260, C 1260M1, C 1260M2, C 1260 M3, AND C 1260M4 (See Table 6.5)

Mix ID

Graded Aggregate

Dry Weight,

g

Cement, g

Water,g

W/CMby

Mass

γ kg/m3

γ lb/ft3

Yield ft3

Flow

Total Air

Content%

A1-WY 990 440 207 0.47 2234.5 139.5 0.03 54.5 1.35 A2-WY 990 440 207 0.47 2251.9 140.6 0.03 78.5 0.48 A4-ID 990 440 207 0.47 2171.7 135.6 0.03 76.0 2.86

A6-NM 990 440 207 0.47 2223.4 138.8 0.03 87.5 0.26 A7-NC 990 440 207 0.47 2274.3 142.0 0.03 36.0 2.49 A9-NE 990 440 207 0.47 2235.0 139.5 0.03 120.0 1.03 A10-PA 990 440 207 0.47 2237.6 139.7 0.03 45.0 1.11 B2-MD 990 440 207 0.47 2236.0 139.6 0.03 50.5 1.09 B4-VA 990 440 207 0.47 2215.7 138.3 0.03 82.0 1.89 C2-SD 990 440 207 0.47 2217.6 138.4 0.03 75.5 2.19 D2-IL 990 440 207 0.47 2220.5 138.6 0.03 78.0 2.88 E2-IA 990 440 207 0.47 2224.1 138.8 0.03 75.0 1.71 E4-NV 990 440 207 0.47 2054.8 128.3 0.03 0.0 1.70 E6-IN 990 440 207 0.47 2233.6 139.4 0.03 103.0 1.49

E8-NM 990 440 207 0.47 2232.9 139.4 0.03 86.0 0.73 Note 1: Aggregate absorption neglected for water calculation

152

Table 7.3: Mortar Mixtures Used to Evaluate the Effect of Class C Fly Ash

Mixture ID

Graded Aggregate

Dry Weight

g

Cementg

H2Og

Class CFly Ash

g

W/CM by

Mass

γ kg/m3

γ lb/ft3

Yield ft3 Flow

Total Air

Content%

WY-FAC-20 990 352 207 88 0.47 2226.0 139.0 0.03 108.0 0.88 WY-FAC-27.5 990 319 207 121 0.47 2224.1 138.8 0.03 117.0 0.68 WY-FAC-35 990 286 207 154 0.47 2216.9 138.4 0.03 116.5 0.72 ID-FAC-20 990 352 207 88 0.47 2181.7 136.2 0.03 97.0 1.68

ID-FAC-27.5 990 319 207 121 0.47 2194.5 137.0 0.03 97.0 0.82 ID-FAC-35 990 286 207 154 0.47 2176.2 135.9 0.03 110.5 1.37

NM-FAC-20 990 352 207 88 0.47 2196.9 137.1 0.03 107.5 0.71 NM-FAC-27.5 990 319 207 121 0.47 2203.1 137.5 0.03 114.5 0.15 NM-FAC-35 990 286 207 154 0.47 2190.7 136.8 0.03 124.5 0.43 VA-FAC-20 990 352 207 88 0.47 2205.7 137.7 0.03 112.5 1.58

VA-FAC-27.5 990 319 207 121 0.47 2206.9 137.8 0.03 119.0 1.25 VA-FAC-35 990 286 207 154 0.47 2214.1 138.2 0.03 117.5 0.65 SD-FAC-20 990 352 207 88 0.47 2181.7 136.2 0.03 82.5 3.04

SD-FAC-27.5 990 319 207 121 0.47 2183.4 136.3 0.03 102.5 2.69 SD-FAC-35 990 286 207 154 0.47 2188.4 136.6 0.03 104.5 2.19 IA-FAC-20 990 352 207 88 0.47 2204.8 137.6 0.02 82.5 2.01

IA-FAC-27.5 990 319 207 121 0.47 2216.7 138.4 0.02 102.5 1.20 IA-FAC-35 990 286 207 154 0.47 2204.8 137.6 0.02 104.5 1.45

Note 1: Aggregate absorption neglected for water calculation

153

Table 7.4: Mortar Mixtures Used to Evaluate the Effect of Class F Fly Ash

Mixture ID

Graded Aggregate

Dry Weight

g

Cementg

H2Og

Class F

Fly Ash

g

W/CM by

Mass

γ kg/m3

γ lb/ft3

Yield ft3 Flow

Total Air

Content%

WY-FAF-15 990 374 207 66 0.47 2228.6 139.1 0.02 98.0 0.62 WY-FAF-25 990 330 207 110 0.47 2226.7 139.0 0.02 113.0 0.11 ID-FAF-15 990 374 207 66 0.47 2195.0 137.0 0.03 92.5 0.94 ID-FAF-25 990 330 207 110 0.47 2202.9 137.5 0.02 113.0 0.00

NM-FAF-15 990 374 207 66 0.47 2195.7 137.1 0.03 99.0 0.62 NM-FAF-25 990 330 207 110 0.47 2182.4 136.2 0.02 104.0 0.64 VA-FAF-15 990 374 207 66 0.47 2196.2 137.1 0.03 91.5 1.87 VA-FAF-25 990 330 207 110 0.47 2214.3 138.2 0.02 96.0 0.47 SD-FAF-15 990 374 207 66 0.47 2216.9 138.4 0.03 83.5 1.33 SD-FAF-25 990 330 207 110 0.47 2206.7 137.8 0.02 100 1.20 IAFAF-15 990 374 207 66 0.47 2206.7 137.8 0.03 83.5 1.60 IA-FAF-25 990 330 207 110 0.47 2206.9 137.8 0.02 100 1.00 * Aggregate absorption neglected for water calculation

Table 7.5: Mortar Mixtures Used to Evaluate the Effect of Silica Fume

Mixture ID

Graded Aggregate

Dry Weight

g

Cementg

H2Og

Silica Fume

g

W/CM by

Mass

γ kg/m3

γ lb/ft3

Yield ft3 Flow

Total Air

Content%

WY-SF-5 990 418 207 22 0.47 2208.8 137.9 0.03 75.5 2.09 WY-SF-10 990 396 207 44 0.47 2183.1 136.3 0.03 52.0 2.94

ID-SF-5 990 418 207 22 0.47 2174.5 135.8 0.03 57.0 2.44 ID-SF-10 990 396 207 44 0.47 2135.7 133.3 0.03 27.5 3.90 NM-SF-5 990 418 207 22 0.47 2201.9 137.5 0.03 74.0 0.93

NM-SF-10 990 396 207 44 0.47 2203.4 137.6 0.03 49.0 0.57 VA-SF-5 990 418 207 22 0.47 2209.1 137.9 0.03 59.0 1.89

VA-SF-10 990 396 207 44 0.47 2203.8 137.6 0.03 31.5 1.83 SD-SF-5 990 418 207 22 0.47 2198.8 137.3 0.03 57.0 2.73

SD-SF-10 990 396 207 44 0.47 2200.3 137.4 0.03 42.0 2.37 IA-SF-5 990 418 207 22 0.47 2228.6 139.1 0.03 57 1.22

IA-SF-10 990 396 207 44 0.47 2216.7 138.4 0.03 42 1.45 * Aggregate absorption neglected for water calculation

154

Table 7.6: Mortar Mixtures Used to Evaluate The Effect of Granulated Slag

Mixture ID

Graded Aggregate

Dry Weight

g

Cement g

H2Og

Granulated Slag

g

W/CM by Mass

γ kg/m3

γ lb/ft3

Yield ft3 Flow

Total Air

Content%

WY-SL-40 990 264 207 176 0.47 2207.4 137.8 0.02 94.0 0.96

WY-SL-55 990 198 207 242 0.47 2206.0 137.7 0.02 79.5 0.46

WY-SL-70 990 132 207 308 0.47 2201.5 137.4 0.02 72.5 0.11

ID-SL- 40 990 264 207 176 0.47 2191.7 136.8 0.02 64.5 0.49

ID-SL- 55 990 198 207 242 0.47 2186.2 136.5 0.02 52.5 0.18

ID-SL- 70 990 132 207 308 0.47 2171.0 135.5 0.02 50.5 0.33

NM-SL-40 990 264 207 176 0.47 2181.5 136.2 0.02 86.0 0.67

NM-SL-55 990 198 207 242 0.47 2178.6 136.0 0.02 72.0 0.25

NM-SL-70 990 132 207 308 0.47 2169.1 135.4 0.02 67.5 0.14

VA-SL-40 990 264 207 176 0.47 2199.5 137.3 0.02 73.5 1.12

VA-SL-55 990 198 207 242 0.47 2207.4 137.8 0.02 71.0 0.21

VA-SL-70 990 132 207 308 0.47 2183.4 136.3 0.02 66.5 0.74

SD-SL- 40 990 264 207 176 0.47 2187.6 136.6 0.02 66.5 2.04

SD-SL- 55 990 198 207 242 0.47 2198.1 137.2 0.02 59.5 1.01

SD-SL- 70 990 132 207 308 0.47 2197.9 137.2 0.02 52.5 0.46

IA-SL- 40 990 264 207 176 0.47 2187.6 136.6 0.02 66.5 2.04

IA-SL- 55 990 198 207 242 0.47 2198.1 137.2 0.02 59.5 0.82

IA-SL- 70 990 132 207 308 0.47 2181.0 136.2 0.02 52.5 1.04

* Aggregate absorption neglected for water calculation

155

Table 7.7: Mortar Mixtures Used to Evaluate the Effect of Lithium Nitrate

Mixture ID LiNO3

Graded Aggregate

Dry Weight

g

Cementg

H2Og

W/CM by Mass

γ kg/m3

γ lb/ft3

Yield Ft3 Flow

Total Air

Content%

WY-LI-21 21 990 440 207 0.47 2175.5 135.8 0.03 76.5 3.86

WY-LI-28 28 990 440 207 0.47 2185.3 136.4 0.03 83.5 3.43

WY-LI-60 60 990 440 207 0.47 2219.6 138.6 0.03 96.0 1.91

ID-LI- 21 21 990 440 207 0.47 2139.2 133.5 0.03 85.0 4.32

ID-LI- 28 28 990 440 207 0.47 2128.0 132.8 0.03 84.0 4.82

ID-LI- 60 60 990 440 207 0.47 2182.9 136.3 0.03 83.0 2.36

NM-LI- 21 21 990 440 207 0.47 2196.5 137.1 0.03 101.0 1.47

NM-LI- 28 28 990 440 207 0.47 2198.6 137.3 0.03 98.0 1.37

NM-LI- 60 60 990 440 207 0.47 2190.9 136.8 0.03 105.5 1.72

VA-LI- 21 21 990 440 207 0.47 2147.6 134.1 0.03 82.0 4.91

VA-LI- 28 28 990 440 207 0.47 2206.6 137.8 0.03 82.5 2.29

VA-LI- 60 60 990 440 207 0.47 2192.7 136.9 0.03 82.2 2.91

SD-LI- 21 21 990 440 207 0.47 2189.9 136.7 0.03 75.5 3.42

SD-LI- 28 28 990 440 207 0.47 2162.9 135.0 0.03 75.2 4.60

SD-LI- 60 60 990 440 207 0.47 2167.1 135.3 0.03 75.9 4.42

* Aggregate absorption neglected for water calculation

156

Table 7.8: Mortar Mixtures Used to Evaluate the Effect of Entrained Air

Mixture ID

Graded Aggregate

Dry Weight

g

Cement g

H2Og

W/CM by

Mass

γ kg/m3

γ lb/ft3

YieldFt3 Flow

Total Air

Content %

EntrainedAir

Content%

WY-AE-4 990 440 207 0.47 2164.1 135.1 0.03 99.5 4.36 3.88 WY-AE-8 990 440 207 0.47 2087.9 130.3 0.03 94.0 7.73 7.25 ID-AE-4 990 440 207 0.47 2084.5 130.1 0.03 96.0 6.76 3.90 ID-AE-8 990 440 207 0.47 1968.8 122.9 0.03 90.5 11.93 9.07

NM-AE-4 990 440 207 0.47 2156.0 134.6 0.03 90.0 3.29 3.02 NM-AE-8 990 440 207 0.47 2012.9 125.7 0.03 98.5 9.70 9.44 VA-AE-4 990 440 207 0.47 2111.9 131.8 0.03 67.5 6.48 4.60 VA-AE-8 990 440 207 0.47 2045.1 127.7 0.03 130 9.44 7.55 SD-AE-4 990 440 207 0.47 2121.0 132.4 0.03 91.5 6.45 4.26 SD-AE-8 990 440 207 0.47 2047.2 127.8 0.03 91.5 9.71 7.52 IA-AE-4 990 440 207 0.47 2151.4 134.3 0.03 91.5 4.92 4.92 IA-AE-8 990 440 207 0.47 2084.0 130.1 0.03 91.5 7.90 7.90

* Aggregate absorption neglected for water calculation

157

Table 7.9: Mortar Mixtures Used to Evaluate the Effect of Calcined Clay

Mixture ID

Graded Aggregate

Dry Weight

g

Cementg

H2Og

Calcined Clay

g

W/CM by

Mass

γ kg/m3

γ lb/ft3

Yield ft3 Flow

Total Air

Content%

WY-CC-17 990 365 207 75 0.47 2186.0 136.5 0.03 91.5 2.40 WY-CC-25 990 330 207 110 0.47 2219.5 138.6 0.02 65.5 0.43 ID-CC-17 990 365 207 75 0.47 2192.6 136.9 0.03 53.0 0.93 ID-CC-25 990 330 207 110 0.47 2190.7 136.8 0.02 44.0 0.55

A6NM-CC-17 990 365 207 75 0.47 2206.2 137.7 0.03 61 0.03 A6NM-CC-25 990 330 207 110 0.47 2178.6 136.0 0.02 60.5 0.82 VA-CC-17 990 365 207 75 0.47 2200.7 137.4 0.03 60 1.55 VA-CC-25 990 330 207 110 0.47 2192.6 136.9 0.02 53.5 1.45 SD-CC-17 990 365 207 75 0.47 2202.6 137.5 0.03 52.5 1.85 SD-CC-25 990 330 207 110 0.47 2196.0 137.1 0.02 54 1.68 IA-CC-25 990 365 207 75 0.47 2195.3 137.0 0.02 55 1.37 IA-CC-25 990 330 207 110 0.47 2183.1 136.3 0.02 52.0 2.07 IN-CC-25 990 330 207 110 0.47 2196.5 137.1 0.02 53.5 0.29 NV-CC-25 990 330 207 110 0.47 2191.2 136.8 0.02 55 0.24

E6-NM-CC-25 990 330 207 110 0.47 2193.4 136.9 0.02 60.5 1.41 * Aggregate absorption neglected for water calculation

158

Table 7.10: Mortar Mixtures Used to Evaluate the Effect of W/C

Mixture ID

Graded Aggregate

Dry Weight

g

Cementg

H2Og

HRWRcc

W/CM by

Mass

γ kg/m3

γ lb/ft3

Yield ft3 Flow

WY-WC-35 990 440 154 5 0.35 2321.2 144.9 0.02 1.76 WY-WC-55 990 440 242 --- 0.55 2203.1 137.5 0.03 0.06 WY-WC-65 990 440 286 --- 0.65 2100.0 131.1 0.03 1.79 ID-WC-35 990 440 154 5 0.35 2286.9 142.8 0.02 1.94 ID-WC-55 990 440 242 --- 0.55 2177.9 136.0 0.03 0.06 ID-WC-65 990 440 286 --- 0.65 2097.6 131.0 0.03 0.83

NM-WC-35 990 440 154 5 0.35 2320.5 144.9 0.02 0.19 NM-WC-55 990 440 242 --- 0.55 2169.8 135.5 0.03 0.16 NM-WC-65 990 440 286 --- 0.65 2106.2 131.5 0.03 0.17 VA-WC-35 990 440 154 5 0.35 2301.2 143.7 0.02 2.39 VA-WC-55 990 440 242 --- 0.55 2177.6 135.9 0.03 1.03 VA-WC-65 990 440 286 --- 0.65 2119.8 132.3 0.03 0.69 SD-WC-35 990 440 154 5 0.35 2276.9 142.1 0.02 3.84 SD-WC-55 990 440 242 --- 0.55 2170.5 135.5 0.03 1.73 SD-WC-65 990 440 286 --- 0.65 2103.6 131.3 0.03 1.80

* Aggregate absorption neglected for water calculation

159

Table 7.11: Mortar Mixtures Used to Count for the Absorption of Aggregates

Aggregate ID

Cement g

AggregateDry

Weight g

H2O g Flow Unit Weight kg/m3

(lb/ft3)

Total Air

Content %

A1-WY 740 1665 361 64.5 2184 (136.3) 2.86 A2-WY 740 1665 361 115 2194 (137.0) 2.29 A4-ID 740 1665 380 108.5 2143 (133.8) 2.78

A6-NM 740 1665 376 109.5 2175 (135.8) 1.18 A7-NC 740 1665 357 41.5 2258 (141.0) 2.67 A9-NE 740 1665 353 116.5 2211 (138.0) 1.75 B2-MD 740 1665 361 69 2205 (137.7) 1.79 B4-VA 740 1665 372 87 2184 (136.3) 2.52 C2-SD 740 1665 353 83.5 2205 (137.7) 2.38 D2-IL 740 1665 378 106 2202 (137.5) 2.18 E2-IA 740 1665 366 97 2182 (136.2) 2.7 E4-NV 740 1665 443 81 1988 (124.1) 1.63 E6-IN 740 1665 366 113 2216 (138.3) 1.38

E8-NM 740 1665 370 98 2200 (137.3) 1.18 Note 1: Refer to Table 5.2 for Nomenclature Note 2: Weights were calculated on a 5-bars batch basis:

160

7.3 ASTM C 1293 MIXTURE PROPORTIONS

ASTM C 1293 was used to investigate the alkali-silica reactivity of all

aggregates listed in Table 5.2. The test was also used to evaluate modification

procedures and mitigation alternatives using two rapidly reactive and one slowly

reactive aggregates. Table 7.12 includes the proportions and fresh concrete properties

of mixtures used to investigate the standard C 1293 at 380C, C 1293 at 600C, and C

1293 in 1N NaOH solution at 380C and 800C.

In the following tables, ASTM C 138 was used to measure the mixtures’ unit

weight, γ, yield, and total air content while ASTM C 143 was used to measure the

slump.

Using the aggregates listed in Table 5.2, 0.6 ft3 concrete mixtures were prepared

to cast seven 3-in. x 3-in. x 11-in. prisms. Three prisms were stored in a closed

container over water at 380C, two prisms were stored in a 1N NaOH solution at 380C,

and two prisms were stored in a 1N NaOH solution at 800C. Small batches (0.2 ft3),

but with the same proportions, were prepared at a later date to cast concrete prisms

for performing C 1293 at 600C. Proportions for these mixtures are listed in Table

7.12. Additional concrete mixtures, listed in Tables 7.13 to 7.20, were prepared to

investigate mitigation alternatives. All these mixtures were used to cast three 3-in. x

3-in. x 11-in. prisms that were stored in a closed container over water at 380C and six

4-in. x 8-in. concrete cylinders that were used to test for compressive strength,

modulus of elasticity, tensile strength, and rapid chloride permeability

161

Table 7.12: Concrete Mix Proportions for ASTM C 1293 and Modified C 1293

Aggregate ID

Coarse Aggregate

SSD Weight lb/yd3

Fine Aggregate

SSD Weight lb/yd3

Cementlb/yd3

Waterlb/yd3

W/CM by

Mass

γ∗

lb/ft3 Yield*

ft3 Slump**

in.

Total Air

Content*

%

A1-WY 1711 1188 710 315 0.45 143.8 0.6 4.50 1.8 A2-WY 1666 1198 710 320 0.45 143.8 0.6 4.00 0.8 A3-ID 1603 1256 710 270 0.45 143.8 0.6 4.50 2.8 A4-ID 1608 1192 710 315 0.45 145.4 0.6 4.50 1.8

A5-NM 1742 1137 710 270 0.45 145.4 0.6 4.50 2.2 A6-NM 1608 1185 710 315 0.45 145.4 0.6 4.75 1.5 A7-NC 1672 1322 710 270 0.45 148.8 0.6 3.50 2.5 A8-VA 1668 1260 710 315 0.45 147.3 0.6 3.50 1.8 A9-NE 1322 1545 710 315 0.45 147.3 0.6 4.00 2.9 A10-PA 1666 1203 710 315 0.45 147.3 0.6 3.50 1.8 B1-MD 1615 1279 710 270 0.45 147.3 0.6 4.00 1.4 B2-MD 1582 1282 710 320 0.45 141.9 0.6 2.50 1.5 B4-VA 1613 1248 710 270 0.45 147.3 0.6 4.00 1.8 C1-SD 1591 1296 710 270 0.45 145.5 0.6 4.25 2.4 C2-SD 1608 1262 710 320 0.45 145.4 0.6 2.50 1.9 D2-IL 1613 1278 710 320 0.45 143.8 0.6 3.75 2.4 E2-IA 1666 1198 710 320 0.45 142.6 0.6 4.00 2.5 E3-NV 1405 1284 710 334 0.45 138.4 0.6 4.25 1.1 E4-NV 1639 1058 710 320 0.45 138.4 0.6 4.00 2.0 E6-IN 1666 1203 710 320 0.45 144.0 0.6 4.50 1.9

E7-NM 1512 1402 710 315 0.45 148.8 0.6 4.50 1.3 E8-NM 1586 1265 710 320 0.45 144.0 0.6 3.00 1.6

* = ASTM C 138 to measure unit weight, γ, yield, and total air content ** = ASTM C 143 to measure the Slump

W/C = Water-to-Cement Ratio by weight γ = Concrete Unit Weight

162

Table 7.13: Concrete Mixtures Used to Investigate the Effect of Air Entrainment

Mixture ID

Control Air

Content %

Coarse Aggregate

SSD Weight lb/yd3

Fine Aggregate

SSD Weight lb/yd3

Cementlb/yd3

Waterlb/yd3

W/C by

Mass

γ∗

lb/ft3 Yield*

ft3 Slump**

in.

EntrainedAir

Content* %

WY-2 0.8 1666 1198 710 360 0.45 140.4 0.6 4.25 2.4 WY-4 0.8 1666 1198 710 360 0.45 137.0 0.6 4.50 4.7 WY-6 0.8 1666 1198 710 360 0.45 133.6 0.6 5.00 7.1 WY-8 0.8 1666 1198 710 360 0.45 130.1 0.6 7.00 9.5 ID-2 1.8 1608 1192 710 315 0.45 140.4 0.6 4.50 2.3 ID-4 1.8 1608 1192 710 315 0.45 137.0 0.6 6.00 4.7 ID-6 1.8 1608 1192 710 315 0.45 133.6 0.6 6.00 7.0 ID-8 1.8 1608 1192 710 315 0.45 130.1 0.6 7.00 9.3

NM-2 1.5 1608 1185 710 315 0.45 140.4 0.6 5.00 2.4 NM-6 1.5 1608 1185 710 315 0.45 137.0 0.6 5.25 4.7 NM-8 1.5 1608 1185 710 315 0.45 133.6 0.6 6.00 7.1

NM-10 1.5 1608 1185 710 315 0.45 130.1 0.6 6.50 9.4 SD-4 1.9 1608 1262 710 337 0.45 140.4 0.6 4.00 2.4 SD-8 1.9 1608 1262 710 337 0.45 133.6 0.6 6.00 7.1 IA-4 2.5 1666 1198 710 320 0.45 137.0 0.6 4.00 3.9 IA-8 2.5 1666 1198 710 320 0.45 133.6 0.6 6.00 6.3

* = ASTM C 138 to measure unit weight, γ, yield, and total air content ** = ASTM C 143 to measure the Slump W/C = Water-to-Cement Ratio γ = Concrete Unit Weight Control Air = Total air of concrete with no admixture (Table 7.12)

Entrained air = Total Air obtained by adding Entraining Agent – Control Air

163

Table 7.14: Concrete Mixtures Used to Investigate the Effect of Silica Fume

Mixture ID

Coarse Aggregate

SSD Weight lb/yd3

Fine Aggregate

SSD Weight lb/yd3

Cementlb/yd3

Waterlb/yd3

Silica Fumelb/yd3

W/CM by

Mass

γ∗

lb/ft3 Yield*

ft3 Slump**

in.

Total Air

Content*

%

WYSF- 5 1666 1198 675 360 36 0.45 143.8 0.6 4.50a 0.8

WYSF-10 1666 1198 630 360 71 0.45 143.8 0.6 5.50b 0.8

ID-SF- 5 1608 1192 675 315 36 0.45 143.8 0.6 3.50a 1.8

ID-SF-10 1608 1192 630 315 71 0.45 143.8 0.6 3.00b 1.8

SD-SF-5 1608 1262 675 337 36 0.45 143.8 0.6 1.25a 1.9 SD-SF-

10 1608 1262 630 337 71 0.45 143.8 0.6 3.00b 1.9

IA-SF- 5 1666 1198 675 337 36 0.45 143.8 0.6 1.50a 1.80

IA-SF-10 1666 1198 630 337 71 0.45 143.8 0.6 3.50b 1.80

* = ASTM C 138 to measure unit weight, γ, yield, and total air content ** = ASTM C 143 to measure the Slump

γ = Concrete Unit Weight W/CM = Water-to-Cementitious-Materials Ratio a = Slump after adding 20cc of Superplasticizer b = Slump after adding 60cc of Superplasticizer

164

Table 7.15: Concrete Mixtures Used to Investigate the Effect of Class C Fly Ash

Mixture ID

Coarse Aggregate

SSD Weight lb/yd3

Fine Aggregate

SSD Weight lb/yd3

Cementlb/yd3

Waterlb/yd3

Class C Fly Ash

lb/yd3

W/CM by

Mass

γ∗

lb/ft3 Yield*

ft3 Slump**

in.

Total Air

Content*

%

WY-FAC-20 1666 1198 568 360 142 0.45 143.2 0.6 4.50 0.8

WY-FAC-27.5

1666 1198 515 360 195 0.45 143.2 0.6 5.00 0.5

WY-FAC-35 1666 1198 462 360 249 0.45 142.5 0.6 4.75 0.9

ID- FAC-20 1608 1192 568 315 142 0.45 143.2 0.6 3.00 1.7

ID- FAC-27.5

1608 1192 515 315 195 0.45 143.2 0.6 3.50 1.5

ID- FAC-35 1608 1192 462 315 249 0.45 142.5 0.6 3.75 1.8

SD- FAC-20 1608 1262 568 337 142 0.45 143.2 0.6 3.00 1.8

SD- FAC-27.5

1608 1262 515 337 195 0.45 143.2 0.6 4.00 1.6

SD- FAC-35 1608 1262 462 337 249 0.45 142.5 0.6 5.00 1.9

IA- FAC-20 1666 1198 568 360 142 0.45 143.2 0.6 3.00 1.73

IA- FAC-27.5

1666 1198 515 360 195 0.45 143.2 0.6 4.00 1.52

IA- FAC-35 1666 1198 462 360 249 0.45 142.5 0.6 5.00 1.83

* = ASTM C 138 to measure unit weight, γ, yield, and total air content ** = ASTM C 143 to measure the Slump

γ = Concrete Unit Weight W/CM = Water-to-Cementitious Materials Ratio

165

Table 7.16: Concrete Mixtures Used to Investigate the Effect of Class F Fly Ash

Mixture ID

Coarse Aggregate

SSD Weight lb/yd3

Fine Aggregate

SSD Weight lb/yd3

Cementlb/yd3

Waterlb/yd3

Class F Fly Ash

lb/yd3

W/CM by

Mass

γ∗

lb/ft3 Yield*

ft3 Slump**

in.

Total Air

Content*

%

WY-FAF-15 1666 1198 604 360 107 0.45 143.2 0.6 4.50 0.6

WY-FAF-25 1666 1198 533 360 178 0.45 142.5 0.6 5.00 0.7

ID-FAF-15 1608 1192 604 315 107 0.45 143.2 0.6 3.00 1.6

ID-FAF-25 1608 1192 533 315 178 0.45 142.5 0.6 3.50 1.7

SD-FAF-15 1608 1262 604 337 107 0.45 143.2 0.6 3.00 1.7

SD-FAF-25 1608 1262 533 337 178 0.45 142.5 0.6 4.00 1.8

IA-FAF-15 1666 1198 604 337 107 0.45 143.2 0.6 3.00 1.61

IA-FAF-25 1666 1198 533 337 178 0.45 142.5 0.6 4.00 1.70

* = ASTM C 138 to measure unit weight, γ, yield, and total air content ** = ASTM C 143 to measure the Slump

γ = Concrete Unit Weight W/CM = Water-to-Cementitious Materials Ratio

166

Table 7.17: Concrete Mixtures Used to Investigate the Effect of Granulated Slag

Mixture ID

Coarse Aggregate

SSD Weight lb/yd3

Fine Aggregate

SSD Weight lb/yd3

Cementlb/yd3

Waterlb/yd3

Slaglb/yd3

W/CM by

Mass

γ∗

lb/ft3 Yield*

ft3 Slump**

in.

Total Air

Content*

%

WY-SL-25 1666 1198 533 360 178 0.45 143.2 0.6 4.50 0.6

WY-SL-50 1666 1198 355 360 355 0.45 141.8 0.6 5.00 0.9

WY-SL-70 1666 1198 213 360 497 0.45 141.1 0.6 4.75a 0.9

ID-SL-25 1608 1192 533 315 178 0.45 143.2 0.6 3.00 1.8

ID-SL-50 1608 1192 355 315 355 0.45 143.2 0.6 3.50 1.9

ID-SL-70 1608 1192 213 315 497 0.45 143.8 0.6 3.75a 1.6

SD-SL-25 1608 1262 533 337 178 0.45 143.2 0.6 3.00 1.9

SD-SL-50 1608 1262 355 337 355 0.45 143.8 0.6 4.00 1.6

SD-SL-70 1608 1262 213 337 497 0.45 143.8 0.6 5.00a 1.7

IA-SL-25 1666 1198 533 337 178 0.45 143.2 0.6 3.25 1.82

IA-SL-50 1666 1198 355 337 355 0.45 143.8 0.6 3.75 1.49

IA-SL-70 1666 1198 213 337 497 0.45 143.8 0.6 5.50a 1.59

* = ASTM C 138 to measure unit weight, γ, yield, and total air content ** = ASTM C 143 to measure the Slump

γ = Concrete Unit Weight W/CM = Wate-to-Cementitious Materials Ratio

a = Slump after adding 10 to 30 cc Superplasticizers

167

Table 7.18: Concrete Mixtures Used to Investigate the Effect of Calcined Clay

Mixture ID

Coarse Aggregate

SSD Weight lb/yd3

Fine Aggregate

SSD Weight lb/yd3

Cementlb/yd3

Waterlb/yd3

Calcined Clay lb/yd3

W/CM by

Mass

γ∗

lb/ft3 Yield*

ft3 Slump**

in.

Total Air

Content*

%

WY-CC-17 1666 1198 589 360 121 0.45 143.2 0.6 4.50 0.6

WY-CC-25 1666 1198 533 360 178 0.45 142.5 0.6 5.00 0.7

ID- CC-17 1608 1192 589 315 121 0.45 143.2 0.6 3.00 1.5

ID- CC-25 1608 1192 533 315 178 0.45 142.5 0.6 3.50 1.7

SD- CC-A7 1608 1262 589 337 121 0.45 143.2 0.6 3.00 1.7

SD- CC-25 1608 1262 533 337 178 0.45 142.5 0.6 4.00 1.8

IA- CC-A7 1666 1198 589 337 121 0.45 143.2 0.6 2.75 1.55

IA- CC-25 1666 1198 533 337 178 0.45 142.5 0.6 3.50 1.70

* = ASTM C 138 to measure unit weight, γ, yield, and total air content ** = ASTM C 143 to measure the Slump

γ = Concrete Unit Weight W/CM = Water-to-Cementitious Materials Ratio

168

Table 7.19: Concrete Mixtures Used to Investigate the Effect of Lithium Nitrate

Mixture ID

Coarse Aggregate

SSD Weight lb/yd3

Fine Aggregate

SSD Weight lb/yd3

Cementlb/yd3

Waterlb/yd3

LiNO3lb/yd3

W/CM by

Mass

γ∗

lb/ft3 Yield*

ft3 Slump**

in.

Total Air

Content*

%

WY-LI-315 1666 1198 710 337 31 0.45 143.8 0.6 4.50 0.8

WY-LI-495 1666 1198 710 326 49 0.45 143.8 0.6 5.00 0.8

WY-LI-900 1666 1198 710 292 89 0.45 143.8 0.6 4.75 1.0

ID-LI-315 1608 1192 710 292 31 0.45 143.8 0.6 3.00 1.8

ID-LI-495 1608 1192 710 281 49 0.45 143.8 0.6 3.50 1.7

ID-LI-900 1608 1192 710 247 89 0.45 143.8 0.6 3.75 1.9

SD-LI-315 1608 1262 710 315 31 0.45 143.8 0.6 3.00 1.9

SD-LI-495 1608 1262 710 304 49 0.45 143.8 0.6 4.00 1.9

SD-LI-900 1608 1262 710 270 89 0.45 143.8 0.6 5.00 2.0

IA-LI-315 1666 1198 710 315 31 0.45 143.8 0.6 2.75 1.81

IA-LI-495 1666 1198 710 304 49 0.45 143.8 0.6 3.75 1.76

IA-LI-900 1666 1198 710 270 89 0.45 143.8 0.6 4.50 1.93

* = ASTM C 138 to measure unit weight, γ, yield, and total air content ** = ASTM C 143 to measure the Slump

γ = Concrete Unit Weight W/CM = Water-to-Cementitious Materials Ratio

169

CHAPTER EIGHT

MISCELLANEOUS TESTING RESULTS

8.1 INTRODUCTION

This Chapter includes information about the aggregates investigated that was

either obtained by performing tests or reported by others. Information includes

physical properties, summarized results of petrographic examination, field

performance status, and any C 1260 and C 1293 results reported by aggregate

producers.

8.2 PHYSICAL PROPERTY TESTS RESULTS

After performing the tests listed in Table 6.1, physical properties of the

aggregates investigated were determined. Table 8.1 lists the measured and calculated

properties for the aggregates listed in Table 5.2.

8.3 PETROGRAPHIC EXAMINATION, CHEMICAL ANALYSIS AND FIELD PERFORMANCE DOCUMENTATION

Table 8.2 includes the chemical analysis results for the aggregates. This analysis

was submitted as part of the petrographic analysis report for each aggregate. Table

8.3 includes the following:

1. Petrographic examination results whether the aggregates contain reactive

materials or not. This information was obtained from petrographic analysis

reports that were submitted by either aggregate producers or departments of

transportation using the aggregates. Detailed information can be found in

Appendix D.

2. Field performance status of aggregates. This information was obtained by getting

input from aggregate producers and Departments of Transportation experienced

170

with the use of these aggregates. Detailed information can be found in Appendix

D.

3. ASTM C 227, C 1260, and C 1293 results that were submitted by aggregate

producers.

Table 8.1: Physical Properties of Aggregates investigated Dry Apparent SSD Abs. DRUW γssd Void Fineness

Agg. Agg. B.S.G. B.S.G. B.S.G. % lb/ft3 lb/ft3 Content, % ModulusID Type Note1 Note1 Note1 Note1 Note2 Note2 Note2 Note3

A1-WY C.A. 2.62 2.67 2.64 0.77 99.8 100.6 39 N/A A2-WY F.A. 2.61 2.66 2.63 0.80 95.7 96.5 41 2.7 A3-ID C.A. 2.52 2.65 2.57 1.9 101.5 103.4 36 N/A A4-ID F.A. 2.52 2.65 2.57 1.90 92.5 94.3 41 2.8

A5-NM C.A. 2.57 2.67 2.61 1.50 100.9 102.4 37 N/A A6-NM F.A. 2.51 2.63 2.56 1.70 100.8 102.5 36 2.92 A7-NC C.A. 2.76 2.81 2.79 0.53 97.8 98.3 43 N/A A8-VA C.A. 2.59 2.65 2.62 1.07 100.2 101.3 38 N/A A9-NE S&G 2.62 2.64 2.62 0.30 116.7 117.1 29 3.8 A10-PA F.A. 2.63 2.69 2.64 1.10 117.5 118.4 30 2.6 B1-MD C.A. 2.79 2.83 2.81 0.50 102.0 102.5 41 N/A B2-MD F.A. 2.60 2.65 2.63 0.78 97.3 98.0 40 3.6 B4-VA F.A. 2.59 2.65 2.62 0.80 100.8 101.1 40 2.9 C1-SD C.A. 2.59 2.65 2.61 0.84 95.8 96.6 41 N/A C2-SD F.A. 2.63 2.65 2.64 0.30 101.4 101.7 38 2.9 D1-IL C.A. 2.63 2.76 2.67 1.81 97.7 99.5 40 N/A D2-IL F.A. 2.64 2.71 2.68 1.80 101.5 103.3 38 2.9 D3-TX C.A. 2.49 2.56 2.56 2.85 95.2 97.9 39 N/A E2-Ia F.A. 2.63 2.63 2.63 1.10 100.2 101.3 39 2.675

E3-NV F.A. 2.15 2.28 2.27 5.70 78.6 83.1 41 2.75 E4-NV C.A. 2.19 2.29 2.29 4.80 81.4 85.3 40 N/A E6-IN F.A. 2.61 2.69 2.64 1.10 106.8 108.0 34 2.79

E7-NM C.A. 2.63 2.70 2.66 0.90 91.0 91.8 45 N/A E8-NM F.A. 2.57 2.66 2.60 1.30 100.8 102.1 37 3.02

Agg. = Aggregate; B.S.G. = Bulk specific gravity; Abs. = Absorption; γssd = SSD unit weight;

DRUW = Dry rodded unit weight = γd; N/A = Not applicable C.A. = Coarse aggregate; F.A. = Fine aggregate Note1: ASTM C 127 for coarse aggregates and ASTM C 128 for fine aggregates Note2: ASTM C 29 Note3: ASTM C 136

171

Table 8.2: Chemical Analysis of Aggregates Agg. CaO

% MgO

% Fe2O3

% Na2O

% K2O%

MnO%

TiO2%

SiO2 %

Al2O3 %

Loss on Ignition

A-WY 2.30 0.54 6.77 2.36 2.67 0.10 0.77 74.62 10.43 1.41 A-ID 2.47 1.15 3.72 2.78 3.31 0.09 0.74 74.02 10.96 1.57

A-NM 1.44 0.57 2.93 1.80 2.60 0.05 0.43 80.65 8.12 1.04 A-NC 1.42 1.98 7.18 2.09 3.84 0.16 0.87 62.68 15.70 3.77

A,B-VA 0.55 0.40 3.23 0.63 2.18 0.09 2.13 84.50 4.01 1.51 A-NE 0.80 0.12 0.45 1.38 2.45 0.01 0.11 88.14 6.05 0.37 B-MD 5.47 5.74 8.92 4.03 0.60 0.21 0.54 59.04 13.23 1.62 C-SD 0.34 0.13 0.13 0.21 0.08 0.01 0.05 97.98 0.59 0.14 D-IL 29.91 20.52 0.29 0.00 0.00 0.02 0.01 0.56 0.45 50.19 E-IA 4.51 1.25 3.03 1.40 1.40 0.07 0.34 78.30 5.88 3.83 E-NV 0.88 0.37 1.17 3.30 3.82 0.09 0.14 74.02 12.55 3.18 E-IN 5.82 1.52 1.77 0.99 1.48 0.04 0.25 77.12 4.35 5.80

E-NM 4.01 0.37 7.41 1.16 1.76 0.13 0.77 75.73 5.35 3.28 This analysis was provided as part of the petrographic analysis report

172

Table 8.3: Summary of Available Documentation on Aggregates Investigated

Aggregate ID

Petrographic Analysis

Reported

Field Performance

ASTM C 1260 (14-Day

Expansion)

ASTM C 1293 (1-Year

Expansion)

ASTM C227

(6-Month Expansion)

A(1,2)-WY Reactive Materials

Reactive N.R. N.R. N.R.

A(3,2)-ID Reactive Materials

Reactive Reactive (0.80 %)

N.R. N.R.

A(5,6)-NM Reactive Materials

Reactive Reactive (1.040 %)

N.R. N.R.

A7-NC Reactive Materials

Reactive N.R. N.R. Reactive

A8-VA No Reactive Materials

N.R. N.R. N.R. N.R.

A9-NE Reactive Materials

Reactive Reactive (0.29 %)

N.R. Innocuous (0.03%)

A10-PA Reactive Materials

Reactive Reactive (0.314 %)

N.R. N.R.

B(1,2)-MD No Reactive Materials

Reactive Inconclusive (0.11 %)

N.R. N.R.

B4-VA No Reactive Materials

N.R. N.R. N.R. N.R.

C(1,2)-SD No Reactive Materials

Reactive N.R. N.R. N.R.

D(1,2)-IL No Reactive Materials

Good with high alkali

cement

N.R. N.R. N.R.

E2-Ia No Reactive Materials

Good with high alkali

cement

Reactive (0.33 %)

N.R. Innocuous (0.03 %)

E(3,4)-NV Reactive Materials

Good with mitigation

N.R. N.R. N.R.

E6-IN No Reactive Materials

Good with high alkali

cement

N.R. N.R. N.R.

E(7,8)-NM Reactive Materials

Good with mitigation

Reactive (0.34 %)

N.R. N.R.

Note1: Refer to Table 5.2 for aggregate notation Note2: Detailed information about properties of aggregates in this Table can be

found in Appendix D. N.R. = No Record

173

8.4 ASTM C 227 RESULTS OF TESTING PERFORMED AS PART OF THIS STUDY

ASTM C 227 procedures were followed with the following exceptions:

1. The cement used had an average alkali content of 1.14% Na2Oequiv.

2. No wicks were used around the sides of the containers.

3. Mixture proportions were controlled by a constant water-cement ratio of 0.47

instead of a constant flow.

4. Expansions were monitored for up to 1-year.

Results of the testing procedures are illustrated in Table 8.4 and Figures 8.1

through 8.3. Mixture proportions used for this test are listed in Table 7.1 that

includes mixture properties including unit weight, flow number, yield and air

content.

Table 8.4: ASTM C 227 Expansion Results for Aggregates investigated

Agg. ID

Expansion, % 14-day 1-month 2-month 3-month 4-month 6-month 9-month 12-month

A1-WY 0.01 0.04 0.06 0.08 0.11 0.14 0.20 0.21 A2-WY 0.01 0.02 0.08 0.13 0.15 0.20 0.23 0.24 A4-ID 0.01 0.05 0.19 0.30 0.37 0.51 0.63 0.69

A6-NM 0.00 0.05 0.21 0.31 0.39 0.49 0.60 0.61 A7-NC 0.00 0.01 0.03 0.07 0.10 0.68 0.74 0.75 A9-NE 0.01 0.01 0.02 0.03 0.04 0.05 0.06 0.07 A10-PA 0.01 0.02 0.02 0.03 0.03 0.04 0.06 0.08 B2-MD 0.01 0.01 0.02 0.03 0.03 0.04 0.06 0.06 B4-VA 0.01 0.02 0.02 0.03 0.04 0.05 0.06 0.07 C2-SD 0.01 0.01 0.02 0.03 0.04 0.06 0.08 0.10 D2-IL 0.00 0.00 0.01 0.02 0.02 0.03 0.04 0.04 E2-IA 0.00 0.00 0.00 0.02 0.02 0.03 0.04 0.04 E4-NV 0.00 0.01 0.02 0.05 0.07 0.09 0.13 0.14 E6-IN 0.00 0.01 0.02 0.04 0.05 0.07 0.08 0.08

E8-NM 0.00 0.01 0.07 0.16 0.21 0.33 0.41 0.43

174

0.000.050.100.150.200.250.300.350.400.450.500.550.600.650.700.75

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Time, months

Exp

ansi

on, %

A1-WYA2-WYA4-IDA6-NMA7-NCA9-NEA10-PA

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Time, months

Exp

ansi

on, %

B2-MDB4-VAC2-SDD2-IL

Figure 8.1: ASTM C 227 Results for Category A Aggregates

Figure 8.2: ASTM C 227 Results of Category B, C, & D Aggregates

175

-0.050.000.050.100.150.200.250.300.350.400.45

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Time, months

Exp

ansi

on, %

E2-IAE4-NVE6-INE8-NM

This test has been heavily criticized in the literature, the major complaint being

that it does not provide for the correct prediction of the alkali-silica reactivity of

several aggregate types, namely slowly reactive aggregates. The standard limit

criteria for the interpretation of the testing results are:

1. Expansions are considered excessive if they exceed 0.05% at 3-months or 0.10%

at 6-months.

2. Expansions greater than 0.05% at 3-months should not be considered excessive if

the 6-month expansions are less than 0.10%.

3. Data for the 3-month test should be considered only when the 6-month results are

not available.

4. Other researchers suggested using a value of 0.10% at 12-months as a criterion

for reactivity.

These criteria were used to generate the following observations:

Figure 8.3: ASTM C 227 Results for Category E Aggregates

176

1. Category A: Aggregates in this category have been identified as being alkali-

silica reactive in field applications (Table 8.3) and have been identified as

reactive using C 1260 and C 1293 (Chapters 9). Using the C 227 results these

aggregates have shown 3-month expansions higher than 0.05% with the

exception of A9-NE and A10-PA (Figure 8.1). In addition, A9-NE and A10-PA

had 6-month and 12-month expansions lower than 0.10%. Thus, using the results

of this test, A9-NE and A10-PA are considered innocuous aggregates, which

does not correlate with the field performance of these aggregates nor does it

correlate with the results of C 1260 and C 1293 generated in this study.

2. Category B and C: Aggregates in these categories have been identified as slowly

reactive aggregates using C 1260 and C 1293 (Chapter 9, and 10) and some have

been identified as being alkali-silica reactive in field applications (Table 8.3). All

three aggregates showed 3-month expansions lower than 0.05% and 6-months

and 12-month expansions lower than 0.10%. Thus, based on the C 227 results

these aggregates are considered innocuous which does not correlate with the

results of C 1260, C 1293, nor the field performance record.

3. Category D: the aggregate in this category has been identified as being

innocuous in field applications (Table 8.3) and innocuous using C 1260 and C

1293 (Chapters 9 and 10). The C 227 results indicated that this aggregate is

innocuous with a 3-month expansion lower than 0.05 and 6-month and 12-month

expansions lower than 0.10%.

4. Category E: Aggregates in this category have been identified as being innocuous

in field applications (Table 8.3) with the exception of E4-NV, which has been

reported as a reactive aggregate. E4-NV had a 3-month expansion slightly higher

than 0.05% and a 12-month expansion higher than 0.10%. Thus, E4-NV is

correctly classified as reactive. According to these results, E8-NM is also

reactive. The other two aggregates (E2-IA and E4-IN) have shown innocuous

177

expansions and are classified as such. This classification correlate well with the

field performance of these aggregates.

In summary, the C 227 results have shown to be not very reliable and several

discrepancies were noted. The procedures failed to predict the potential reactivity of

all slowly reactive aggregates and two reactive aggregates. These facts, coupled with

the criticism about the test in the literature, generated the conclusion that the ASTM

C 227 testing procedures are not reliable and should not be used to predict the

potential alkali-silica reactivity of aggregates. It should be noted that an aggregate or

an aggregate-cement combination that fail this test is probably reactive and should be

rejected or mitigated.

178

CHAPTER NINE

ASTM C 1260 RESULTS AND DISCUSSION

“TEST METHOD FOR POTENTIAL REACTIVITY OF AGGREGATES (MORTAR-BAR-TEST)”

9.1 ASTM C 1260

ASTM C 1260 is used to test for the potential alkali-silica reactivity of aggregates

within two weeks. Aggregates are separated into specified sieve sizes, combined

using specified amounts of each sieve size, and mixed with cement to make

1”x1”x11” mortar bars. After 24-hours of moist curing, mortar bars are stored for an

additional 24 hours in water maintained at 800C after which the bars are stored in a

1N NaOH solution maintained at 800C. Expansion readings are taken at 4, 7, 11, and

14 days of storage in the NaOH solution. Fourteen-day expansions higher than

0.20% are considered reactive, 14-day expansions lower than 0.10% are considered

innocuous, and 14-day expansions between 0.10% and 0.20% are considered

inconclusive. Aggregates were tested using these procedures described in details in

section 6.3.2, and the results are shown in this chapter. Table 9.1 includes a summary

of expansion readings for the aggregates and Figures 9.1 through 9.3 illustrate the

expansions in a graphical form. Mixture proportions for these tests were included in

Table 7.2.

179

Table 9.1: ASTM C 1260 Expansion Test Results Aggregate Expansion, %

ID 4-day 7-day 11-day 14-day 21-day 28-day A1-WY 0.12 0.18 0.21 0.24 0.31 0.32 A2-WY 0.18 0.24 0.27 0.29 0.34 0.37 A4-ID* 0.45 0.62 0.75 0.79 0.89 0.95 A6-NM 0.50 0.67 0.83 0.91 1.04 1.12 A7-NC* 0.13 0.23 0.28 0.31 0.39 0.48 A9-NE* 0.07 0.14 0.23 0.28 0.39 0.43 A10-PA* 0.02 0.07 0.19 0.26 0.40 0.49 B2-MD* 0.04 0.07 0.09 0.11 0.16 0.18 B4-VA* 0.02 0.06 0.11 0.15 0.25 0.28 C2-SD 0.05 0.10 0.14 0.17 0.24 0.30 D2-IL* 0.01 0.01 0.02 0.02 0.03 0.03 E4-NV 0.04 0.06 0.18 0.25 0.44 0.64 E6-IN* 0.03 0.10 0.20 0.25 0.34 0.43 E2-IA 0.12 0.24 0.38 0.42 0.53 0.62

E8-NM 0.10 0.22 0.33 0.36 0.46 0.54 * = The test was performed twice and the expansions shown

are the average of two tests. Note: Expansions were the average of three prisms for each aggregate

180

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 5 10 15 20 25 30

Curing Days

Exp

ansi

on, % B2-MD*

B4-VA*C2-SDD2-IL*

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0 5 10 15 20 25 30

Curing Days

Exp

ansi

on, %

A1-WYA2-WYA4-ID*A6-NMA7-NC*A9-NE*A10-PA*

Figure 9.1: ASTM C 1260 Expansions for Category A Aggregates

Figure 9.2: ASTM C 1260 Expansions for Category B, C, & D Aggregates

181

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0 5 10 15 20 25 30

Curing Days

Exp

ansi

on, % E4-NV

E6-IN*E2-IAE8-NM

Criteria proposed in the standard ASTM C 1260 document to determine the

reactivity of aggregates are as follows: 14-day expansions lower than 0.10% are

considered innocuous, 14-day expansions between 0.10% and 0.20% are considered

inconclusive, and 14-day expansions greater than 0.20% are considered reactive.

Based on the results of the study conducted by Starks (1993) in the Strategic

Highway Research Program (SHRP C-343) (details in Chapter 4), it was concluded

that aggregates showing 14-day expansions higher than 0.08% are considered

reactive and 14-day expansions lower than 0.08% are considered innocuous.

However, this conclusion was based on a limited amount of data (one aggregate), and

the 0.10% has been adequately justified in the literature for a voluminous amount of

aggregates. As a result, the 0.10% criterion was adopted throughout this study for the

interpretation of the ASTM C 1260 results.

Figure 9.3: ASTM C 1260 Expansions for Category E Aggregates

182

Aggregates listed in Category A are rapidly reactive and have shown 14-day

expansions varying between 0.24 and 0.91%, all larger than 0.20%. Aggregates

listed in Category B and C are slowly reactive and have shown 14-day expansions

varying between 0.12 and 0.17%. Aggregates listed in Category D are innocuous

and have shown 14-day expansions varying between 0.03 and 0.06%. Category E

aggregates have shown 14-day expansions varying between 0.25 and 0.42% all larger

than 0.20%, which imply that all Category E aggregates are reactive. Petrographic

analysis and field performance of E2-IA and E6-IN indicate that the aggregates are

not reactive (Table 8.3) and this was reinforced by the results of ASTM C 1293

presented in Chapter 10 that showed that these aggregates are innocuous after 1-year

of testing. Given these discrepancies, it can be concluded that the ASTM C 1260

results were too severe for E2-IA and E6-IN. On the other hand, petrographic

analysis concluded that E4-NV and E8-NM were found to contain reactive materials

(Table 8.3), which means that the aggregates are expected to have 14-day expansions

larger than 0.20% and should be listed as Category A aggregates.

Using the 14-day expansion criterion of 0.10%, it was possible to efficiently

detect highly reactive aggregates that showed 14-day expansions higher than 0.20%.

The test was also particularly useful in detecting slowly reactive aggregates that

showed expansions between 0.10% and 0.20%. Thus, 14-day expansions between

0.10% and 0.20% should not be considered inconclusive but should be considered

slowly reactive. The power of these procedures lies in being able to detect reactive

aggregates, which was demonstrated by the correct classification of E4-NV and E8-

NM. Even though the aggregates were erroneously listed as being innocuous, the test

allowed the correct assessment of their reactivity.

The procedures however, were found to be too severe for E2-IA and E6-IN which

have been reported to have good field performance (Table 8.3), good petrographic

analysis results (Table 8.3), and innocuous when tested according to C 1293 results

(Chapter 10) but were found to be reactive when tested with C 1260.

183

9.2 ASTM C 1260 PERFORMED BY THE NATIONAL AGGREGATE ASSOCIATION (NAA)

In order to test the accuracy of the C 1260 testing procedures, three aggregates,

used in this study, were tested by the NAA. The aggregates were A2-WY, A4-ID,

and C2-SD (Table 5.2). The same cement used in this study was used by the NAA.

The C 1260 expansions for these aggregates were reported as shown in Table 9.2.

Table 9.2: ASTM C 1260 Performed by NAA Aggregate

ID Expansion, %

3-day 7-day 11-day 14-day A2-WY 0.19 0.22 0.26 0.27 A4-ID 0.43 0.58 0.68 0.73 C2-SD 0.06 0.11 0.16 0.20

A comparison between the NAA results and the results generated in this study is

included in Tables 9.3 and 9.4.

Table 9.3: Differences Between NAA Results and

Results Generated in this Study A2-WY A4-ID C2-SD

4-Day + 5.0% - 5.0% + 17.0% 7-Day 0.0% 6.5% + 8.0% 11-Day - 6.0% - 9.0% + 19.0% 14-Day - 5.0% - 8.0% + 12.0%

Positive = percentage the NAA result is larger than the one generated in this study Negative = percentage the NAA result is smaller than the one generated in this study

An inter-laboratory study evaluating the variation of C 1260 resulted in the

following conclusion (section 4.5.1.3.1): “For mortars giving average expansions

after 14 days in solution of more than 0.30%, the muti-laboratory coefficient of

variation has been found to be 14.9%. Therefore, the results of two properly

conducted tests in different laboratories on specimens of a sample of aggregate

184

should not differ by more than 42% of the mean expansion (Rogers 1996).” Table

12.2 shows the variation from the mean of all readings. It can be seen from that table

that the variations between the results of both labs are small and the results can be

considered accurate. This was done to measure the accuracy of the testing being

performed for this study and the results show that testing was conducted properly.

Table 9.4: Variations from the Mean of the NAA and the C 1260 Results

Generated Through this Study 4-Day 7-Day 11-Day 14-Day A2-WY

NAA, expansion, % 0.19 0.22 0.26 0.274 UT, Expansion, % 0.18 0.24 0.27 0.29

Mean 0.19 0.23 0.27 0.28 NAA Variation 2.0% 4.0% 3.0% 2.7% UT Variation 2.0% 4.0% 3.0% 2.7%

A4-ID NAA, expansion, % 0.43 0.58 0.68 0.73 UT, Expansion, % 0.45 0.62 0.75 0.79

Mean 0.44 0.60 0.72 0.76 NAA Variation 3.0% 3.5% 5.0% 4.0% UT Variation 3.0% 3.5% 5.0% 4.0%

C2-SD NAA, expansion, % 0.06 0.11 0.16 0.20 UT, Expansion, % 0.05 0.10 0.14 0.17

Mean 0.06 0.10 0.15 0.18 NAA Variation 7.0% 4.0% 8.0% 6.0% UT Variation 8.0% 4.0% 10.0% 6.0%

185

9.3 MODIFIED C 1260: EXPANSIONS UP TO 56-DAYS

Selected aggregates were retested using the C 1260 procedures but expansions

were recorded over 56 days in order to investigate the possibility of a better

interpretation of the results. Mixture proportions for these procedures were the same

as before and are listed in Table 7.2 which also includes mixture properties such as

yield, unit weight, air content, and flow number. Expansions are shown in Table 9.5

and Figures 9.5 through 9.7.

Roger (1993) suggested expanding the C 1260 readings to 56 days instead of 14

and using the following criteria for assessing the reactivity of aggregates: 0.15% at

14 days, 0.33% at 28 days, and 0.48% at 56 days. Thus, for an aggregate to be

classified as reactive, it should exceed all three criteria. A study conducted in

Australia (Shayan 1992) concluded that these criteria were not effective in detecting

the reactivity of several slowly reactive aggregates. These procedures were used to

determine whether Category E aggregates could be accurately classified using these

limits and whether these limits are effective with slowly reactive aggregates. That is

why only two Category A aggregates were tested while all Category B, C, D, and E

were investigated.

Table 9.5: Expansions up to 56 days in 1N NaOH Curing Solution Expansion, %

Aggregate 4-day 7-day 11-day 14-day 21-day 28-day 42-day 56-dayA1-WY 0.06 0.16 0.21 0.24 0.30 0.35 0.42 0.48 A9-NE 0.04 0.10 0.17 0.21 0.30 0.37 0.47 0.56 B4-VA 0.01 0.04 0.08 0.12 0.19 0.26 0.37 0.46 C2-SD 0.02 0.07 0.10 0.13 0.20 0.26 0.38 0.48 D2-IL 0.01 0.01 0.02 0.02 0.03 0.03 0.04 0.05 E2-IA 0.10 0.28 0.41 0.47 0.56 0.65 0.77 0.85 E4-NV 0.04 0.11 0.21 0.30 0.47 0.66 0.99 1.35 E6-IN 0.02 0.09 0.18 0.23 0.34 0.43 0.56 0.67

E8-NM 0.09 0.26 0.35 0.40 0.46 0.53 0.63 0.71

186

A comparison between the 14-day expansions generated for the 56-day

procedures were compared to the 14-day expansions generated earlier using ASTM

C 1260 is shown in Figure 9.4. ASTM C 1260 was essentially repeated and the 14-

day expansions of both set of data should be comparable and should give an

indication about the variation of the procedures when the same materials and

procedures are used and when the tests are performed by the same laboratory

operators.

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

0.500

A1-WY A9-NE B4-VA C2-SD D2-IL E2-IA E4-NV E6-IN E8-NM

Aggregate Investigated

14-D

ay E

xpan

sion

, %

14-day expansions generated for the 56-day procedures

14-day expansions generated for the 14-day procedures

It can be seen from Figure 9.4 that the expansions are comparable with some

differences that are comparable to the differences noted between the data generated

for this study and the data examined by the NAA.

Figure 9.4: Comparison Between the 14-Day Expansions Generated for the ASTM C 1260 and for the 56-Day Extended ASTM C 1260

187

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60

Time, Days

Exp

ansi

on, %

A1-WYA9-NE

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60

Time, Days

Exp

ansi

on, % B4-VA

C2-SDD2-IL

Figure 9.5: 56-Day C 1260 Results for Category A Aggregates

Figure 9.6: 56-Day C 1260 Results for Category B, C, & D Aggregates

188

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60

Time, Days

Exp

ansi

on, % E2-IA

E4-NVE6-INE8-NM

Using the criteria of 0.33% at 28 days, and 0.48% at 56 proposed by Rogers

(1996), the following observations were recorded:

1. Slowly reactive aggregates B4-VA and C2-SD showed 28-day expansions of

0.26%. The two aggregates also exhibited 56-day expansions of 0.46% and

0.48% respectively. Both the 28-day and the 56-day expansions of both

aggregates were lower than the proposed limits and as such should be classified

as innocuous, which is false. These two aggregates are slowly reactive aggregates

as it was determined using ASTM C 1260 (Table 9.1), ASTM C 1293 (Table

10.1), and field performance (Table 8.3). Thus using the proposed criteria it was

not possible to correctly characterize the reactivity of the slowly reactive

aggregates tested.

Figure 9.7: 56-Day C 1260 Results for Category E Aggregates

189

2. Using the same line of reasoning, all Category E aggregates were all

characterized as reactive, which is true for E4-NV and E8-NM but not E2-IA and

E6-IN.

3. Using the proposed criteria for the 28-day and 56-day expansions, Category D

aggregates were correctly characterized as innocuous.

4. In summary, the criteria were not effective in detecting slowly reactive

aggregates and correctly characterizing Category E aggregates.

9.4 MODIFIED C 1260: ADJUSTING WATER CONTENT TO ACCOUNT FOR AGGREGATE ABSORPTION

For proportioning the mortar bar mixtures, ASTM C 1260 requires using a water-

cement ratio that neglects the absorption of the processed aggregates. As mentioned

earlier, aggregates for these procedures are separated into sieve sizes and then

combined in a required percentage. This results in a high-fines aggregate with an

unknown absorption. That is why the absorption is neglected. In order to account for

the absorption of aggregates and obtain a constant 0.47 water-cement ratio for all

mixtures, the C 1260 procedures were repeated but using the absorption of

aggregates in calculating the water content. Mixture proportions for these tests were

included in Table 7.11. Results are shown in Table 9.6 and Figures 9.8 through 9.10.

190

Table 9.6: C 1260 Expansions for Mixtures Adjusted for Aggregate Absorption Aggregate

ID Expansion, %

0-day 4-day 7-day 11-day 14-day 21-day 28-day A2-WY 0.00 0.17 0.24 0.26 0.29 0.33 0.36 A4-ID 0.00 0.37 0.53 0.64 0.69 0.75 0.81

A6-NM 0.00 0.48 1.01 1.02 1.02 1.02 1.03 A7-NC 0.00 0.18 0.28 0.34 0.38 0.46 0.55 A9-NE 0.00 0.08 0.15 0.25 0.32 0.39 0.45 B2-MD 0.00 0.03 0.04 0.08 0.11 0.14 0.17 C2-SD 0.00 0.05 0.07 0.11 0.17 0.24 0.28 D2-IL 0.00 0.00 0.00 0.01 0.02 0.03 0.03 E2-IA 0.00 0.27 0.40 0.51 0.57 0.61 0.65 E4-NV 0.00 0.09 0.21 0.38 0.49 0.70 0.91 E6-IN 0.00 0.06 0.15 0.26 0.32 0.33 0.34

E8-NM 0.00 0.22 0.32 0.42 0.46 0.54 0.61

Increasing the water content of the mortar bars to satisfy the absorption of

aggregates and keeping a constant water-cement ratio of 0.47, resulted in the same

aggregate classification as the standard C 1260 procedures. The 14-day expansions

were slightly higher but still resulted in the same aggregate classification. The

additional water resulted in a much better workability of mortar bar mixtures as can

be seen from the flow numbers in Tables 7.2 (Standard Mixtures) and 7.11 (Adjusted

Water). Table 7.11 shows higher flow numbers and better workability. Still the

results increased slightly, and the aggregates were classified in the same categories.

It looks like these procedures can be used without affecting the testing results.

However, before making that conclusion additional testing should be performed

using aggregates that have 14-day expansions close to the 0.10% limit.

191

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Time, Days

Exp

ansi

on, %

A2-WYA4-IDA6-NMA7-NCA9-NE

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Time, Days

Exp

ansi

on, % B2-MD

C2-SDD2-IL

Figure 9.8: Modified Water C 1260 Expansions for Category A Aggregates

Figure 9.9: Modified Water C 1260 Expansions for Category B, C, & D Aggregates

192

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Time, Days

Exp

ansi

on, % E2-IA

E4-NVE6-INE8-NM

Figure 9.10: Modified Water C 1260 Expansions for Category E Aggregates

193

9.5 MODIFIED C 1260: USING A POLYNOMIAL FITTING PROCEDURE FOR INTERPRETATION OF RESULTS

An attempt was made to use a polynomial fit procedure on the C 1260 expansion

test results versus time for each of the tested aggregates and then to plot the

coefficients of these curves against each other. Results are shown in Figure 9.11.

This process is discussed in more details by Johnston (Johnston 1994), and was

mentioned in section 4.18.5 of this document.

There was a separation between reactive and innocuous aggregates as shown by

the two lines in Figure 9.11. These lines were developed using the expansion

readings over a duration of 14 days (specified in C 1260). The more reactive

aggregates were to the left of the graph and aggregate reactivity diminished from left

to right. Slowly reactive aggregates (Categories B and C) fell in between the two

lines. Most of the slowly reactive aggregates and innocuous aggregates were

-0.40

-0.20

0.00

0.20

0.40

0.60

0.80

-0.08 -0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 0.08

Coefficient, A2

Coe

ffic

ient

, A1 Category A

Category BCategory CCategory ECategory D

Innocuous Line A1 = -4.6821*A2 + 0.0024

Reactive Line A1 = -7.3833*A2 + 0.0868

Figure 9.11: Polynomial Regression Coefficients A1 vs. A2

Expansion = A2*Time + A1*SQRT(Time) + A0

194

concentrated in the area where the lines meet. In this area the lines are too close to be

able to make a definite identification of the reactivity of aggregates. As a result, it

was concluded that these procedures are not very accurate in assessing the reactivity

of aggregates and interpreting the C 1260 expansions.

9.6 MODIFIED C 1260: USING KOLMOGOROV-AVRAMI-MEHL-JOHNSTON’S MODEL FOR INTERPRETATION OF RESULTS

Johnston evaluated the Kolmogorov-Avrami-Mehl-Johnston model in his 1998

paper. He concluded that using the model allows the correct prediction of an

aggregate reactivity with ln(k) equal to -6 being the separating value between

reactive and innocuous aggregates. Aggregates with ln(k) greater than -6 are reactive

and aggregates with ln(k) lower than -6 are innocuous. The model is discussed in

more details in section 4.18.5 of this document. The model was applied to Table 5.2

aggregates, and results are shown in Figure 9.12.

195

0.00

0.50

1.00

1.50

2.00

2.50

-10.0 -8.0 -6.0 -4.0 -2.0 0.0ln (Avrami Rate Constant k)

Avr

ami E

xpon

ent M Category A

Category BCategory CCategory DCategory E

Innocuous Slowly Reactive

Reactive

All Category D aggregates had ln(k) values smaller than –6 and M values larger

than 1. All Category A aggregates had ln(k) values larger than –6 and M values

smaller than 1. Category B and C aggregates had ln(k) values between –6 and –4 and

M values close to 1. Three of the Category E aggregates had ln(k) values larger than

–6 while one had a value slightly smaller than –6.

The K-A-M-J model is better than the polynomial fitting procedures. It provides a

better visualization and is more accurate. However, the model was not successful in

correctly predicting the reactivity of Category E aggregates. It resulted in the same

conclusions as the ones generated using the 14-day expansion of 0.10% criterion.

Thus, even though the model is a more realistic representation of the mortar bar

expansions, it did not provide new advantages. The classification of aggregates was

identical using the K-A-M-J model and the 14-day expansion criterion.

Figure 9.12a: Avrami’s Exponent M versus ln(k) illustrating Avrami’s Equation

Kolmogorov-Avrami-Mehl-Johnson Model Normal Results

196

9.6.1 K-A-M-J’s Model Applied to NAA Data

The NAA performed C 1293 and C 1260 on several aggregates, and the results

were listed in Table 4.17. As can be seen in that table, there is no correlation between

the C 1260 and C 1293 results. Most of the aggregates were tested innocuous with C

1293 while reactive with C 1260. This is basically the same problem as the Category

E problem (C 1260 is too severe for some aggregates). The K-A-M-J model was used

to evaluate these data, and results are shown in Figure 9.12b.

0.0

0.5

1.0

1.5

2.0

2.5

-10 -8 -6 -4 -2 0

Ln (Rate Constant K)

Exp

onen

t M

Innocuous Slowly Rapidly Reactive ReactiveFailed C 1260 Passed C 1293

Failed C 1260 Failed C 1293

From Table 4.17 it can be seen that aggregates with Lot numbers 007,008, 017,

043, 049, 052, 055, 060, 088, 129, and 139 (empty diamonds in Figure 9.12b) were

found to be reactive based on the C 1260 results and innocuous based on the C 1293

results. Thus, C 1260 was too severe for all these aggregates. The C 1260 data were

used to draw the K-A-M-J plot shown in Figure 9.12b, and it can be seen that all

these aggregates showed ln(k) values larger than –6. Thus, the K-A-M-J model

Figure 9.12b: K-A-M-J’s Model Results For NAA C 1260 Data

197

resulted in the same conclusions as the ones generated using C 1260 (the aggregates

are showing as reactive while passing the C 1293 test). The K-A-M-J did not provide

new information; it is basically a different way of arriving at the same results as for

the standard C 1260.

9.6.2 K-A-M-J’s Model Applied to Virginia’s Data

C 1260 data of several aggregates from Virginia were included in Table 4.12.

Again, C 1260 data were used to develop a K-A-M-J diagram that shows the

obtained ln (K) values in Figure 9.12c.

0

0.5

1

1.5

2

2.5

-10 -8 -6 -4 -2 0

Ln (Rate Constant K)

Exp

onen

t M

Innocuous Slowly Rapidly Reactive Reactive

Blacksburg

Warrenton

Basically, all aggregates were found to be reactive in field applications with the

exception of aggregates from Blacksburg and Warrenton. A K-A-M-J plot was

Figure 9.12c: K-A-M-J’s Model Results For Virginia Aggregates

198

generated as Figure 9.12c where it can be seen that all aggregates showed ln(k)

values larger than –6 with the exception of the Blacksburg aggregate that showed a

ln(k) value smaller than –6. In Table 4.12 it can be seen that the Blacksburg

aggregate was found to be innocuous showing 14-day expansion of 0.09% when

tested using C 1260, which corresponded to a ln(k) value of –6.2, slightly smaller

than –6. Thus, the same conclusion was generated using ASTM C 1260 and the K-A-

M-J model.

On the other hand, the Warrenton aggregate was innocuous in the field but

showed C 1260, 14-day expansion, equals to 0.13%, which is slightly above the

limit, and thus, was labeled as Reactive. Using Figure 9.12c indicated that this

aggregate has a ln(k) value slightly larger than –6 which classifies that aggregate as

reactive. Thus, using the K-A-M-J’s model, it was possible to regenerate the C 1260

conclusion. The model did not correlate with the field performance but with the

expansions generated using C 1260.

The rest of the aggregates were reactive in the field and were classified as reactive

using both C 1260 procedures and K-A-M-J’s model. Thus, the same conclusions

that were obtained using the C 1260 procedures were generated using the K-A-M-J

model. Again, results indicate that the model is a more sophisticated method for

saying the same thing.

9.7 MODIFIED C 1260: CHANGING THE MOLARITY OF THE TESTING SOLUTION

In order to investigate the effect of the cement alkali content on ASR using C

1260, the investigated aggregates were tested in solutions with varying molarities,

namely, 1N (standard), 0.75N, 0.5N, and 0.25N. This was also performed to

determine whether using a lower concentration for the curing solution could result in

more reliable results. Mixture proportions used for the standard test (Table 7.2) were

199

used, also. Results for this set of testing are illustrated in Tables 9.6 through 9.9 and

Figures 9.13 through 9.18. Detailed expansions for all aggregates investigated, under

the different molarity solutions, are included in Appendix A.

Table 9.6: Expansions of Category A Aggregates (Different Molarity Solutions) Mixture

ID Expansion, %

4-Day 7-Day 11-Day 14-Day 21-Day 28-Day A1-WY 1N 0.12 0.18 0.21 0.24 0.31 0.32

A1-WY 0.75N 0.05 0.11 0.17 0.20 0.24 0.25 A1-WY 0.50N 0.01 0.03 0.05 0.06 0.10 0.12 A1-WY 0.25N 0.01 0.01 0.01 0.02 0.03 0.04

A2-WY 1N 0.18 0.24 0.27 0.29 0.34 0.37 A2-WY 0.75N 0.11 0.17 0.21 0.25 0.28 0.34 A2-WY 0.50N 0.02 0.05 0.08 0.09 0.13 0.14 A2-WY 0.25N 0.01 0.01 0.02 0.02 0.03 0.05

A4-ID 1N 0.45 0.62 0.75 0.79 0.89 0.95 A4-ID 0.75N 0.31 0.49 0.64 0.72 0.79 0.88 A4-ID 0.50N 0.08 0.18 0.27 0.30 0.40 0.43 A4-ID 0.25N 0.01 0.01 0.06 0.09 0.16 0.21 A6-NM 1N 0.50 0.67 0.83 0.91 1.04 1.12

A6-NM 0.75N 0.37 0.58 0.76 0.86 0.97 1.11 A6-NM 0.50N 0.10 0.21 0.30 0.33 0.45 0.51 A6-NM 0.25N 0.01 0.01 0.07 0.12 0.22 0.29

A7-NC 1N 0.13 0.23 0.28 0.31 0.39 0.48 A7-NC 0.75N 0.06 0.16 0.24 0.29 0.33 0.40 A7-NC 0.50N 0.01 0.02 0.04 0.06 0.10 0.11 A7-NC 0.25N 0.01 0.01 0.01 0.02 0.02 0.02

A9-NE 1N 0.07 0.14 0.23 0.28 0.39 0.43 A9-NE 0.75N 0.02 0.04 0.08 0.12 0.20 0.27 A9-NE 0.50N 0.02 0.03 0.04 0.06 0.12 0.17 A9-NE 0.25N 0.01 0.01 0.01 0.01 0.01 0.01 A10-PA 1N 0.02 0.07 0.19 0.26 0.40 0.49

A10-PA 0.75N 0.01 0.03 0.08 0.18 0.34 0.53 A10-PA 0.50N 0.02 0.02 0.03 0.04 0.10 0.21

200

Table 9.7: Expansions of Category B, C, & D Agg. (Different Molarity Solutions)

Mixture ID

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

B2-MD 1N 0.04 0.07 0.09 0.11 0.16 0.18 B2-MD 0.75N 0.02 0.03 0.06 0.08 0.11 0.17 B2-MD 0.50N 0.01 0.01 0.03 0.04 0.07 0.10 B2-MD 0.25N 0.00 0.02 0.02 0.02 0.02 0.03

B4-VA 1N 0.02 0.06 0.11 0.15 0.25 0.28 B4-VA 0.75N 0.02 0.04 0.05 0.10 0.19 0.25 B4-VA 0.50N 0.01 0.02 0.03 0.04 0.08 0.11 B4-VA 0.25N 0.01 0.01 0.01 0.02 0.02 0.02

C2-SD 1N 0.05 0.10 0.14 0.17 0.24 0.30 C2-SD 0.75N 0.03 0.06 0.07 0.11 0.19 0.25 C2-SD 0.50N 0.01 0.02 0.05 0.07 0.11 0.15 C2-SD 0.25N 0.00 0.01 0.02 0.02 0.02 0.02

D2-IL 1N 0.00 0.01 0.02 0.02 0.03 0.03 D2-IL 0.75N 0.00 0.01 0.02 0.02 0.02 0.03 D2-IL 0.50N 0.00 0.01 0.01 0.01 0.02 0.02 D2-IL 0.25N 0.00 0.00 0.01 0.01 0.01 0.01

201

Table 9.8: Expansions of Category E Aggregates (Different Molarity Solutions)

Mixture ID

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

E2-IA 1N 0.12 0.24 0.38 0.42 0.53 0.62 E2-IA 0.75N 0.10 0.17 0.31 0.37 0.45 0.48 E2-IA 0.50N 0.00 0.01 0.02 0.03 0.04 0.04 E2-IA 0.25N 0.00 0.00 0.01 0.02 0.05 0.07 E4-NV 1N 0.04 0.06 0.18 0.25 0.44 0.64

E4-NV 0.75N 0.05 0.06 0.13 0.17 0.31 0.41 E4-NV 0.50N 0.02 0.04 0.05 0.09 0.14 0.20 E4-NV 0.25N 0.00 0.01 0.02 0.02 0.02 0.03

E6-IN 1N 0.03 0.10 0.20 0.25 0.34 0.43 E6-IN 0.75N 0.02 0.05 0.12 0.16 0.27 0.33 E6-IN 0.50N 0.01 0.01 0.02 0.04 0.07 0.12 E6-IN 0.25N 0.00 0.01 0.01 0.01 0.01 0.01 E8-NM 1N 0.10 0.22 0.33 0.36 0.46 0.54

E8-NM 0.75N 0.04 0.09 0.19 0.22 0.29 0.33 E8-NM 0.50N 0.01 0.02 0.03 0.04 0.05 0.06 E8-NM 0.25N 0.00 0.01 0.01 0.02 0.04 0.07

202

Table 9.9: 14-Day Expansions of the different Testing Solutions 14-Day Expansions, %

Aggregate ID 1N NaOH 0.75N NaOH 0.50N NaOH 0.25N NaOH A1-WY 0.24 0.20 0.06 0.02 A2-WY 0.29 0.25 0.09 0.02 A4-ID 0.79 0.72 0.30 0.09

A6-NM 0.91 0.86 0.33 0.12 A7-NC 0.31 0.29 0.06 0.02 A9-NE 0.28 0.12 0.06 0.01 A10-PA 0.26 0.18 0.04 0.02 B2-MD 0.11 0.08 0.04 0.02 B4-VA 0.15 0.10 0.04 0.02 C2-SD 0.17 0.11 0.07 0.02 D2-IL 0.02 0.02 0.01 0.01 E2-IA 0.42 0.37 0.03 0.02 E4-NV 0.25 0.17 0.09 0.02 E6-IN 0.25 0.16 0.04 0.01

E8-NM 0.36 0.22 0.04 0.02

203

0.000.040.080.120.160.200.240.280.320.360.400.440.480.520.560.600.640.680.720.760.800.840.880.920.96

A1-WY A2-WY A4-ID A6-NM A7-NC A9-NE A10-PA

Investigated Aggregate

14-D

ay E

xpan

sion

, %

1N NaOH0.75N NaOH0.50N NaOH0.25N NaOH

0.000.020.040.060.080.100.120.140.160.18

B2-MD B4-VA C2-SD D2-IL

Investigated Aggregate

14-D

ay E

xpan

sion

, %

1N NaOH0.75N NaOH0.50N NaOH0.25N NaOH

Figure 9.13: 14-Day Expansion Comparison Between Different Curing Solutions, Category A Aggregates

Figure 9.14: 14-Day Expansion Comparison Between Different Curing Solutions Category B, C, & D Aggregates

204

0.000.040.080.120.160.200.240.280.320.360.400.440.48

E2-IA E4-NV E6-IN E8-NM

Investigated Aggregate

14-D

ay E

xpan

sion

, %

1N NaOH0.75N NaOH0.50N NaOH0.25N NaOH

As mentioned earlier in section 4.18.2, the varying levels of normalities could

be used to determine a cement alkali level below which the aggregates do not exhibit

deleterious expansions. These different normalities corresponds to cement alkali

content defined by equation 9.1 that is the same as equation 4.4 (Starks, 1993):

LmolescwONaOH /06.0022.0

/2339.0][ ±+=− (Eq 9.1)

The following list of figures will illustrate the generated expansion results using

1N, 0.75N, 0.50N, and 0.25N NaOH solutions. On each figure, the corresponding

cement alkali content is indicated on a separate axis.

Figure 9.15: 14-Day Expansion Comparison Between Different Curing Solutions Category E Aggregates

205

0.000.100.200.300.400.500.600.700.800.901.00

0 0.2 0.4 0.6 0.8 1 1.2

NaOH Solution Normality

14-D

ay E

xpan

sion

, % A1-WYA2-WYA4-IDA6-NMA7-NCA9-NEA10-PA

0.000.020.040.060.080.100.120.140.160.180.20

0 0.2 0.4 0.6 0.8 1 1.2

NaOH Solution Normality

14-D

ay E

xpan

sion

, %

B2-MDB4-VAC2-SDD2-IL

Figure 9.16: Category A Results at Different Solution Normalities and Cement Alkali Content

0.39 0.67 0.95 1.22 1.50

Cement Alkali Na2Oequiv.

0.39 0.67 0.95 1.22 1.50

Figure 9.17: Category B, C, & D Results at Different Solution Normalities and Cement Alkali Content

Cement Alkali Na2Oequiv.

206

0.000.040.080.120.160.200.240.280.320.360.400.440.48

0 0.2 0.4 0.6 0.8 1 1.2

NaOH Solution Normality

14-D

ay E

xpan

sion

, %

E2-IAE4-NVE6-INE8-NM

Starks (1993) was the first to investigate these procedures (Section 4.18.2). He

suggested that the test failure criteria must be adjusted progressively downward from

0.08% at 1.0N to a minimum of about 0.02% as solution normality decreases to

about 0.6N (Figure 4.3). Thus, for the 0.5N (0.81% Na2Oequiv.) and 0.25N (0.46%

Na2Oequiv.) NaOH solutions, the failure criterion should be 0.02% and for the 0.75N

(1.15% Na2Oequiv.) NaOH solution the failure criterion should be 0.04%. These

criteria were used to evaluate the result listed above.

Results indicated that as the solution normality decreased the expansions

decreased progressively. The following observations were recorded:

0.39 0.67 0.95 1.22 1.50

Figure 9.18: Category E Results at Different Solution Normalities and Cement Alkali Content

Cement Alkali Na2Oequiv.

207

1. The highly reactive aggregates A4-ID and A6-NM of Category A were reactive

even when tested using the 0.25N solution (0.46% Na2Oequiv.).

2. The moderately reactive aggregates of Category A, namely A1-WY, A2-WY,

A7-NC, A9-NE, and A10-PA showed 14-day expansions lower than 0.02% when

tested using the 0.25N solution (0.46% Na2Oequiv.). When 0.50N solution was

used all Category A aggregates showed expansions higher than the proposed

limit of 0.04%.

3. A solution normality of 0.25N (0.46% Na2Oequiv.) was required to decrease the

14-day expansions of slowly reactive aggregates of Categories B and C below

0.02%. Testing at a higher cement alkali content of 0.81% Na2Oequiv. (i.e. higher

solution normality of 0.50N) resulted in 14-day expansions higher than the safe

limit of 0.04%.

4. Category E aggregates had similar behavior to the slowly reactive aggregates. A

solution normality of 0.25N (0.46% Na2Oequiv.) was required to decrease the 14-

day expansions below 0.02%. Testing at a higher cement alkali content of 0.81%

Na2Oequiv. (i.e. higher solution normality of 0.50N) resulted in 14-day expansions

higher than the safe limit of 0.04%. This contradicts the field performance reports

of E2-IA which indicate that the aggregate has been successfully used in field

application with cement alkali contents higher than 0.9%. In addition, E2-IA and

E6-IN have both passed the C 1293 test (corresponding to 1.25% alkali content).

Thus, these procedures are very conservative and very severe for these

aggregates.

5. These observations are summarized in Table 9.10.

208

Table 9.10: Effect of Na2Oequiv. Content on ASR Using ASTM C 1260

Aggregate ID

C 1260 14-Day

Expansiona

Na2Oequiv. Cement Content 1.15% 0.81% 0.46%

NaOH Solution Normality 0.75Nb 0.50Nc 0.25Nc

A1-WY 0.24% H.R.

Reactive Reactive Innocuous

A2-WY 0.29% H.R.

Reactive Reactive Innocuous

A4-ID 0.79% H.R.

Reactive Reactive Reactive

A6-NM 0.91% H.R.

Reactive Reactive Reactive

A7-NC 0.31% H.R.

Reactive Reactive Innocuous

A9-NE 0.28% H.R.

Reactive Reactive Innocuous

A10-PA 0.26% H.R.

Reactive Reactive Innocuous

B2-MD 0.12% S.R.

Reactive Reactive Innocuous

B4-VA 0.15% S.R.

Reactive Reactive Innocuous

C2-SD 0.17% S.R.

Reactive Reactive Innocuous

D2-IL 0.02% Innocuous

Innocuous Innocuous Innocuous

E4-NV 0.25% H.R.

Reactive Reactive Innocuous

E6-IN 0.25% H.R.

Reactive Reactive Innocuous

E2-IA 0.42% H.R.

Reactive Reactive Innocuous

E8-NM 0.36% H.R.

Reactive Reactive Innocuous

aH.R. = ASTM C 1260 14-day expansion > 0.20% aS.R. = 0.10% < ASTM C 1260 14-day expansion < 0.20%

aInnocuous = ASTM C 1260 14-day expansion < 0.10% bReactive = 14-day expansion > 0.04% ; Innocuous = 14-day expansion < 0.04% cReactive = 14-day expansion > 0.02% ; Innocuous = 14-day expansion < 0.02%

209

In summary, changing the solution molarity was not an effective modification of

the ASTM C 1260. Decreasing the solution normality will not solve the severity of

ASTM C 1260. However, changing the NaOH solution normality can be used to

evaluate the effect of cement Na2Oequiv. content on ASR. These procedures are very

conservative and will result in a worst-case scenario. Using the proposed limit, it was

found that a cement alkali content of about 0.5% Na2Oequiv. was effective in

decreasing the 14-day expansions to safe levels for moderately and slowly reactive

aggregates. Highly reactive aggregates were still showing deleterious expansions at

that level.

210

CHAPTER TEN

ASTM C 1293 TESTS RESULTS AND DISCUSSION

“TEST METHOD FOR CONCRETE AGGREGATES BY DETERMINATION OF LENGTH CHANGE OF CONCRETE DUE TO ALKALI-SILICA

REACTION”

10.1 ASTM C 1293

ASTM C 1293 is a concrete prism test that is used to test for the potential alkali-

silica reactivity of aggregates and concrete mixtures. The test consists of casting

three 3”x3”x11” concrete prisms using the aggregate in question and storing the

prisms over water, in a sealed container with wicks covering the sides, at 380C. Some

of the test procedures requirements include the use of (1) a cement content of 708 ±

17 lb, (2) a volume of coarse aggregate per unit volume of concrete of 0.70 ± 0.2%

based on the oven-dry-rodded weight, and (3) a water-cement ratio of 0.42 to 0.45 by

mass. The alkali content of the prisms, Na2Oequiv., is increased to 1.25% by adding

NaOH to the mixing water. Expansions are measured periodically over a period of

one year. Concrete mixtures exhibiting one-year expansions larger than 0.040% are

considered reactive while mixtures showing one-year expansions lower than 0.040%

are considered innocuous.

Aggregates listed in Table 5.2 were tested using the ASTM C 1293 procedures

described in section 6.3.3 and the results are shown in Tables 10.1 through 10.3 and

Figures 10.1 through 10.4. Mixture proportions for these tests were included in Table

7.12.

211

Table 10.1: ASTM C 1293 Results for Category A Aggregates Expansion, %

Time A1-WY A2-WY A3-ID A4-ID A5-NM A6-NM A7-NC A8-VA A9-NE A10-PA1-week 0.005 0.003 0.015 0.019 0.000 0.006 0.000 0.015 0.006 0.008 2-week 0.010 0.005 0.008 0.026 0.009 0.013 0.002 0.017 0.015 0.011 4-week 0.014 0.009 0.008 0.039 0.019 0.048 0.001 0.024 0.019 0.012 6-week 0.018 0.010 0.009 0.092 0.026 0.117 0.002 0.017 0.020 0.017 8-week 0.020 0.013 0.016 0.141 0.034 0.175 0.004 0.021 0.025 0.017 13-week 0.030 0.018 0.020 0.216 0.048 0.266 0.010 0.024 0.031 0.024 18-week 0.034 0.028 0.030 0.267 0.068 0.320 0.025 0.031 0.035 0.024 26-week 0.048 0.067 0.043 0.319 0.077 0.371 0.057 0.040 0.036 0.035 39-week 0.069 0.109 0.053 0.350 0.086 0.400 0.077 0.051 0.037 0.039 52-week 0.073 0.107 0.058 0.379 0.084 0.411 0.085 0.047 0.051 0.043

Table 10.2: ASTM C 1293 Results for Category B, C, & D Aggregates Expansion, %

Time B1-MD B2-MD B4-VA C1-SD C2-SD D2-IL 1-week 0.000 0.006 0.001 0.001 0.010 0.003 2-week 0.002 0.004 0.005 0.003 0.006 0.004 4-week 0.004 0.015 0.008 0.006 0.015 0.007 6-week 0.007 0.016 0.007 0.010 0.017 0.008 8-week 0.009 0.019 0.010 0.014 0.019 0.010 13-week 0.012 0.026 0.013 0.022 0.025 0.014 18-week 0.020 0.029 0.016 0.036 0.030 0.016 26-week 0.028 0.041 0.022 0.048 0.043 0.019 39-week 0.036 0.045 0.030 0.061 0.051 0.024 52-week 0.040 0.046 0.040 0.063 0.053 0.022

212

Table 10.3: Standard ASTM C 1293 Results for Category E Aggregates Expansion, %

Time E2-IA E3-NV E4-NV E6-IN E7-NM E8-NM 1-week 0.009 0.003 0.001 0.002 0.000 0.001 2-week 0.011 0.005 0.001 0.005 0.000 0.001 4-week 0.014 0.008 0.004 0.007 0.001 0.002 6-week 0.015 0.014 0.003 0.008 0.006 0.003 8-week 0.016 0.015 0.005 0.010 0.006 0.005

13-week 0.019 0.018 0.014 0.011 0.010 0.012 18-week 0.021 0.023 0.041 0.018 0.014 0.046 26-week 0.027 0.029 0.046 0.019 0.024 0.048 39-week 0.028 0.029 0.048 0.022 0.026 0.050 52-week 0.025 0.058 0.060 0.022 0.063 0.064

0.000.040.080.120.160.200.240.280.320.360.400.44

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Days

Exp

ansi

on, %

A1-WYA2-WYA3-IDA4-IDA5-NMA6-NMA7-NCA8-VAA9-NEA10-PA

Figure 10.1a: ASTM C 1293 Results for Category A Aggregates

213

0.000.010.020.030.040.050.060.070.080.090.10

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Days

Exp

ansi

on, %

A1-WYA3-IDA5-NMA7-NCA8-VA

0.000.040.080.120.160.200.240.280.320.360.400.44

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Days

Exp

ansi

on, %

A2-WYA4-IDA6-NMA9-NEA10-PA

Figure 10.1b: ASTM C 1293 Results for Coarse Aggregates of Category A

Figure 10.1c: ASTM C 1293 Results for Fine Aggregates of Category A

214

-0.01

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Days

Exp

ansi

on, %

B1-MDB2-MDB4-VAC1-SDC2-SDD2-IL

-0.02

0.00

0.02

0.04

0.06

0.08

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Days

Exp

ansi

on, %

E2-IAE3-NVE4-NVE6-INE7-NME8-NM

Figure 10.2: ASTM C 1293 Results for Category B, C, & D Aggregates

Figure 10.3: ASTM C 1293 Results for Category E Aggregates

215

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0.32

0.36

0.40

0.44

WY ID A-NM MD SD NV E-NM

Investigated Source

12-M

onth

Exp

ansi

on, %

Fine AggregateCoarse Aggregate

An expansion limit of 0.040%, after one year (52 weeks) of testing, was used as a

cut off point between reactive and innocuous aggregates. This limit is what the

standard test calls for and is the limit that is most accepted and used in the literature.

As can be seen from the results above, Category A aggregates, which are highly

reactive, have all shown one-year expansions higher than 0.040%. The expansions

varied from 0.047% to 0.308%. Categories B and C aggregates, which are slowly

reactive, have also shown one-year expansions higher than 0.040% and varying

between 0.040% and 0.063%. Only one Category D aggregate (Innocuous) was

tested and it showed one-year expansion lower than 0.040% specifically, 0.022%.

E4-NV and E8-NM of Category E were found to be reactive with one-year

expansions higher than 0.040%. The coarse aggregates corresponding to these

Figure 10.4: Comparison Between the 12-month Expansions of Tested Coarse and Fine Aggregates from the Same Source

216

aggregate, E3-NV and E8-NM, showed lower expansions than the fine aggregates

however they still were found to be reactive. This correlates well with the field

performance record, and the petrographic analysis of these aggregates, shown in

Table 8.3. E2-IA and E6-IN of Category E were found to be innocuous with one-year

expansions lower than 0.040%, which also correlates well with the field performance

and the petrographic analysis reported in Table 8.3. As a result, using ASTM C 1293,

it was possible to predict the potential alkali-silica reactivity of all aggregates

investigated in a manner that correlated with the field performance records of these

aggregates. This was the only test that showed was capable of correctly portraying

the filed performance of all aggregates. When tested in accordance with ASTM C

1260, E2-IA and E6-IN which have had good field performance records, were found

to be reactive but were found to be innocuous when tested in accordance with C

1293. That is why the C 1260 procedures were labeled as being too severe for some

aggregates.

A comparison between expansions of coarse and fine aggregates from the same

source was included in Figure 10.4 where it can be seen that, with the exception of

SD aggregates, coarse aggregates showed much lower expansions than their

corresponding fine aggregates. This difference can be explained by the fact that fine

aggregates have a larger surface area than coarse aggregates and thus more reactive

silica surface is exposed to alkalis and as a result, higher expansions in shorter

amount of time are expected. Still the reactivity classification of coarse and fine

aggregates from the same source was the same for all combinations.

217

10.2 MODIFIED C 1293: PRISMS STORED IN A 1N NAOH SOLUTION AT 80OC

As mentioned earlier, ASTM C 1293 requires monitoring the expansions of

concrete prisms over a period of one year in order to obtain the final results. In an

effort to decrease the testing period and generate results in a shorter period of time,

ASTM C 1293 concrete prisms were stored in a 1N NaOH solution maintained at

800C. These measures are expected to accelerate the alkali-silica reaction. Mixture

proportions for these tests are the same as the standard C 1293 and are listed in Table

7.12. Results of these procedures are included in Tables 10.4 through 10.6 and

Figures 10.5 through 10.7. C 1293 procedures were followed for the fabrication of

prisms; however, the storage conditions were modified.

Table 10.4: Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category A Aggregates

Expansion, % Time A1-WY A2-WY A3-ID A4-ID A5-NM A6-NM A7-NC A8-VA A9-NE A10-PA

1-week 0.004 0.049 0.102 0.181 0.039 0.191 0.042 0.109 0.105 0.099 2-week 0.012 0.100 0.123 0.244 0.070 0.259 0.045 0.119 0.128 0.115 4-week 0.037 0.151 0.159 0.318 0.099 0.332 0.052 0.118 0.209 0.159 6-week 0.060 0.202 0.192 0.363 0.120 0.383 0.057 0.145 0.272 0.210 8-week 0.074 0.254 0.223 0.392 0.144 0.418 0.066 0.162 0.330 0.266 13-week 0.109 0.305 0.281 0.443 0.184 0.482 0.073 0.187 0.418 0.409 18-week 0.124 0.345 0.338 0.478 0.208 0.523 0.081 0.201 0.477 0.551 26-week 0.151 0.395 0.443 0.529 0.499 0.581 0.097 0.223 0.548 0.694 39-week 0.176 0.445 0.548 0.566 0.582 0.622 0.133 0.244 0.619 0.836 52-week 0.201 0.495 0.653 0.602 0.665 0.663 0.170 0.266 0.690 0.979

218

Table 10.5: Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category B, C, & D Aggregates

Expansion, % Time B1-MD B2-MD B4-VA C1-SD C2-SD D2-IL

1-week 0.047 0.085 0.040 0.099 0.087 0.005 2-week 0.055 0.104 0.051 0.121 0.113 0.006 4-week 0.064 0.141 0.097 0.092 0.148 0.006 6-week 0.072 0.154 0.100 0.174 0.164 0.010 8-week 0.070 0.210 0.119 0.180 0.209 0.016

13-week 0.095 0.268 0.155 0.230 0.266 0.019 18-week 0.099 0.320 0.192 0.251 0.304 0.028 26-week 0.097 0.387 0.245 0.280 0.379 0.028 39-week 0.128 0.442 0.297 0.293 0.449 0.027 52-week 0.160 0.497 0.349 0.306 0.519 0.027

Table 10.6: Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category E Aggregates

Expansion, % Time E2-IA E3-NV E4-NV E6-IN E7-NM E8-NM

1-week 0.059 0.046 0.047 0.049 0.068 0.079 2-week 0.115 0.054 0.092 0.054 0.077 0.126 4-week 0.207 0.063 0.189 0.068 0.092 0.176 6-week 0.253 0.068 0.267 0.090 0.101 0.209 8-week 0.276 0.074 0.332 0.109 0.108 0.230

13-week 0.315 0.089 0.478 0.154 0.121 0.279 18-week 0.342 0.099 0.585 0.193 0.131 0.314 26-week 0.385 0.157 0.896 0.259 0.145 0.374 39-week 0.428 0.252 1.207 0.325 0.153 0.435 52-week 0.471 0.692 1.518 0.391 0.322 0.495

219

0.000.100.200.300.400.500.600.700.800.901.001.10

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

Exp

ansi

on, %

A1-WYA2-WYA3-IDA4-IDA5-NMA6-NMA7-NCA8-VAA9-NEA10-PA

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0.32

0.36

0 1 2 3 4 5

Time, Weeks

Exp

ansi

on, %

A1-WYA2-WYA3-IDA4-IDA5-NMA6-NMA7-NCA8-VAA9-NEA10-PA

Figure 10.5a: 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category A Aggregates

Figure 10.5b: Four-Week Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category A Aggregates

220

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

Exp

ansi

on, %

B1-MDB2-MDB4-VAC1-SDC2-SDD2-IL

0.00

0.04

0.08

0.12

0.16

0 1 2 3 4 5

Time, Weeks

Exp

ansi

on, %

B1-MDB2-MDB4-VAC1-SDC2-SDD2-IL

Figure 10.6a: 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category B, C, and D Aggregates

Figure 10.6b: Four-Week Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category B, C, and D Aggregates

221

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

Exp

ansi

on, %

E2-IAE3-NVE4-NVE6-INE7-NME8-NM

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0 1 2 3 4 5

Time, Weeks

Exp

ansi

on, %

E2-IAE3-NVE4-NVE6-INE7-NME8-NM

Figure 10.7a: 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category E Aggregates

Figure 10.7b: Four-Week Expansions of Concrete Prisms Stored in 1N NaOH solution at 80oC for Category E Aggregates

222

A proposed limit of 0.040% after 4weeks of testing was used to differentiate

between reactive and innocuous aggregates. Thus, 4-week expansions greater than

0.040% are indicative of reactive aggregates and vice versa. This limit was proposed

by researchers in the literature and was found to be most realistic.

From results shown in Figures 10.5 through 10.7, it can be seen that all aggregates

in Categories A, B, and C were classified as reactive and Category D aggregate was

classified as innocuous. These conclusions correlate well with the standard C 1293

test results as far as characterizing the reactivity of aggregates. Using these

procedures, Category E aggregates were all classified as reactive including E2-IA

and E6-IN, which is not in correlation with the standard C 1293 results. This means

that storing the concrete prisms in a 1N NaOH solution at 800C was too severe for

these aggregates. In addition, when tested using the standard C 1293 procedures, A9-

NE, A10-PA, and B2-MD exhibited one-year expansions lower than the expansion of

A5-NM but when tested using the 1N NaOH solution at 800C, all three aggregates

exhibited expansions that are higher than the A5-NM expansion (A5-NM was chosen

as the comparison aggregate). This means that these procedures were too severe

resulting in over estimating aggregate reactivity. Other aggregates exhibited similar

problems. Table 10.7 summarizes the above comparison.

223

Table 10.7: Summary of Generated Results: ASTM C 1293 vs 1N NaOH at 800C Using Respectively

0.040% at one-year and 0.040% at Four-Week as Failure Criteria

Field

Performance

100% R.H. 380C

Standarda

1N NaOH 800C

Modifiedb

A1-WY Reactive Reactive Reactive A2-WY Reactive Reactive Reactive A3-ID Reactive Reactive Reactive A4-ID Reactive Reactive Reactive

A5-NM Reactive Reactive Reactive A6-NM Reactive Reactive Reactive A7-NC Reactive Reactive Reactive A8-VA Reactive Reactive Reactive A9-NE Reactive Reactive Reactive A10-PA Reactive Reactive Reactive B1-MD Reactive Reactive Reactive B2-MD Reactive Reactive Reactive B4-VA Reactive Reactive Reactive C1-SD Reactive Reactive Reactive C2-SD Reactive Reactive Reactive D1-IL Innocuous Innocuous Innocuous E2-Ia Innocuous Innocuous Reactive

E3-NV Reactive Reactive Reactive E4-NV Reactive Reactive Reactive E6-IN Innocuous Innocuous Reactive

E7-NM Reactive Reactive Reactive E8-NM Reactive Reactive Reactive

a = ASTM C 1293 failure criterion is 0.040% at one year b = Failure criterion is 0.040% at 4 weeks Shaded area indicate aggregates with discrepancies

In an effort to solve that problem, the failure criterion of 0.040% after 4 weeks of

testing was changed and made less lenient. E2-IA and E6-IN, which according to

ASTM C 1293 and the field performance data should be innocuous, exhibited 1-

week expansions of 0.059% and 0.049% respectively when tested using the 1N

NaOH solution at 800C procedures. These were the lowest expansions recorded for

these two aggregates. Thus, in order for these procedures to produce results that

224

correlate with ASTM C 1293 and the field performance data of E2-IA and E6-IN, a

1-week expansion limit of 0.06% should be chosen as a cut off point between

reactive and innocuous aggregates. This is the only criterion that will result in E2-IA

and E6-IN to be innocuous aggregates. Using this criterion, 0.06% expansion after 1

week of testing, resulted in false results for A1-WY, A2-WY, A5-NM, and A7-NC

indicating that these aggregates are innocuous with 1-week expansions lower than

0.06%. All these aggregates were classified as highly reactive when tested in

accordance with C 1260 and C 1293 and have had a bad field performance record as

mentioned in Table 8.3. The same erroneous results were generated for the slowly

reactive aggregates B1-MD and B4-VA. In addition, the reactive aggregates of

Category E, E3-NVand E4-NV, were labeled as innocuous. This is illustrated in

Table 10.8. As a result, using the criterion of 0.06% expansion after 1 week of testing

is not a good limit to use. Using the 4-week criterion of 0.040% resulted in better

results than the 1-week criterion, however, the results were on the high side.

A plot comparing these procedures to the standard C 1293 is included in Figure

10.8 where the above discrepancies are illustrated. E2-IA and E6-IN that showed

ASTM C 1293 one-year expansions lower than 0.040% have exhibited 4-week

expansions that are much higher than the proposed limit of 0.040%. In addition, the

450 line on the plot indicates the poor correlation between the ASTM C 1293

expansion results and the results generated by storing the concrete prisms in a 1N

NaOH solution at 800C.

225

Table 10.8: Summary of Generated Results: ASTM C 1293 vs 1N NaOH at 800C Using Respectively

0.040% at one-year and 0.060% at 1-week as Failure Criteria

Field

Performance

100% R.H. 380C

Standarda

1N NaOH 800C

Modifiedb

A1-WY Reactive Reactive Innocuous A2-WY Reactive Reactive Innocuous A3-ID Reactive Reactive Reactive A4-ID Reactive Reactive Reactive

A5-NM Reactive Reactive Innocuous A6-NM Reactive Reactive Reactive A7-NC Reactive Reactive Innocuous A8-VA Reactive Reactive Reactive A9-NE Reactive Reactive Reactive A10-PA Reactive Reactive Reactive B1-MD Reactive Reactive Innocuous B2-MD Reactive Reactive Reactive B4-VA Reactive Reactive Innocuous C1-SD Reactive Reactive Reactive C2-SD Reactive Reactive Reactive D1-IL Innocuous Innocuous Innocuous E2-Ia Innocuous Innocuous Reactive

E3-NV Reactive Reactive Innocuous E4-NV Reactive Reactive Innocuous E6-IN Innocuous Innocuous Reactive

E7-NM Reactive Reactive Reactive E8-NM Reactive Reactive Reactive

a = ASTM C 1293 failure criterion is 0.040% at one year b = Failure criterion is 0.06% at 1 weeks Shaded area indicate aggregates with discrepancies

226

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0.32

0.36

0.00 0.04 0.08 0.12 0.16 0.20 0.24 0.28 0.32 0.36

ASTM C 1293 1-Year Expansions, %

4-w

eek

Exp

ansi

on, %

(1

N a

t 80-

deg.

)

E2-IA

E6-IN

ASTM C 1293

Failure Criterion

Modified C 1293 Failure

Criterion

These procedures are the same as the ones used for the C 1260 procedures

(Mortar-Bar Test), and in both tests E2-IA and E6-IN were classified as reactive

even though they have good performance in the field and passed ASTM C 1293. In

addition, Starks (1993) and Fournier (1992) investigated aggregates using these

procedures, and they concluded that they are inadequate. Several innocuous

aggregates showed higher expansions than reactive aggregates. These procedures are

inadequate and should not be used to differentiate between reactive and innocuous

aggregates.

Figure 10.8: Comparison Between the Standard C 1293 procedures and Modified C 1293 Storing Prisms in 1N NaOH at 800C

227

10.3 MODIFIED C 1293: PRISMS STORED IN A 1N NAOH SOLUTION AT 38OC

As mentioned earlier, ASTM C 1293 requires monitoring the expansions of

concrete prisms over a period of one year in order to obtain the final results. In an

effort to decrease the testing period and generate results in a shorter period of time,

ASTM C 1293 concrete prisms were stored in a 1N NaOH solution maintained at

380C. These measures are expected to accelerate the alkali-silica reaction. Mixture

proportions for these tests are the same as for the standard C 1293 and are listed in

Table 7.12. Procedures are also similar to C 1293 with the exception of storage

environment. Results of these procedures are included in Tables 10.9 through 10.11

and Figures 10.9 through 10.11.

Table 10.9: Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category A Aggregates

Expansion, % Time A1-WY A2-WY A3-ID A4-ID A5-NM A6-NM A7-NC A8-VA A9-NE A10-PA

1-week 0.002 0.012 0.022 0.015 0.133 0.015 0.011 0.034 0.024 0.031 2-week 0.000 0.011 0.024 0.019 0.138 0.021 0.015 0.035 0.026 0.032 4-week 0.005 0.013 0.023 0.036 0.114 0.058 0.015 0.037 0.033 0.039 6-week 0.011 0.014 0.027 0.064 0.118 0.096 0.018 0.038 0.035 0.043 8-week 0.010 0.018 0.027 0.090 0.147 0.130 0.022 0.047 0.038 0.043 13-week 0.017 0.030 0.045 0.144 0.155 0.194 0.030 0.053 0.049 0.050 18-week 0.024 0.063 0.058 0.186 0.162 0.238 0.042 0.059 0.057 0.057 26-week 0.034 0.092 0.084 0.242 0.172 0.297 0.058 0.066 0.069 0.063 39-week 0.043 0.122 0.123 0.292 0.186 0.352 0.068 0.073 0.081 0.070 52-week 0.051 0.151 0.163 0.343 0.199 0.407 0.078 0.079 0.093 0.076

228

Table 10.10: Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category B, C, & D Aggregates

Expansion, % Time B1-MD B2-MD B4-VA C1-SD C2-SD D2-IL

1-week 0.020 0.023 0.011 0.026 0.020 0.013 2-week 0.020 0.027 0.012 0.027 0.020 0.014 4-week 0.020 0.029 0.012 0.027 0.023 0.014 6-week 0.022 0.026 0.013 0.029 0.022 0.015 8-week 0.022 0.030 0.014 0.029 0.024 0.014

13-week 0.028 0.038 0.019 0.041 0.031 0.021 18-week 0.034 0.050 0.023 0.050 0.040 0.026 26-week 0.042 0.071 0.045 0.064 0.052 0.025 39-week 0.049 0.103 0.055 0.077 0.072 0.025 52-week 0.057 0.135 0.065 0.091 0.091 0.026

Table 10.11: Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category E Aggregates

Expansion, % Time E2-IA E3-NV E4-NV E6-IN E7-NM E8-NM

1-week 0.006 0.014 0.012 0.015 0.013 0.014 2-week 0.007 0.015 0.014 0.015 0.010 0.013 4-week 0.007 0.017 0.019 0.016 0.012 0.016 6-week 0.011 0.018 0.029 0.018 0.013 0.019 8-week 0.015 0.019 0.048 0.018 0.014 0.024

13-week 0.020 0.022 0.089 0.022 0.020 0.060 18-week 0.030 0.025 0.122 0.033 0.026 0.103 26-week 0.036 0.030 0.161 0.038 0.033 0.145 39-week 0.041 0.032 0.201 0.042 0.040 0.187 52-week 0.046 0.069 0.240 0.046 0.095 0.229

229

0.000.040.080.120.160.200.240.280.320.360.400.44

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

Exp

ansi

on, %

A1-WYA2-WYA3-IDA4-IDA5-NMA6-NMA7-NCA8-VAA9-NEA10-PA

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0.32

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

Exp

ansi

on, %

A1-WYA2-WYA3-IDA4-IDA5-NMA6-NMA7-NCA8-VAA9-NEA10-PA

Figure 10.9a: 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category A Aggregates

Figure 10.9b: 13-Week (6-Month) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category A Aggregates

230

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

Exp

ansi

on, %

B1-MDB2-MDB4-VAC1-SDC2-SDD2-IL

0.00

0.02

0.04

0.06

0.08

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

Exp

ansi

on, %

B1-MDB2-MDB4-VAC1-SDC2-SDD2-IL

Figure 10.10a: 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category B, C, & D Aggregates

Figure 10.10b: 13-Week (6-month) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category B, C, & D Aggregates

231

0.000.020.040.060.080.100.120.140.160.180.200.220.240.26

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

Exp

ansi

on, %

E2-IAE3-NVE4-NVE6-INE7-NME8-NM

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

Exp

ansi

on, %

E2-IAE3-NVE4-NVE6-INE7-NME8-NM

Figure 10.11a: 52-Week (one-year) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category E Aggregates

Figure 10.11b: 13-Week (6-month) Expansions of Concrete Prisms Stored in 1N NaOH solution at 38oC for Category E Aggregates

232

A proposed expansion limit for these procedures is 0.040% after 6 months (26

weeks) of testing. Thus, 26-week expansions higher than 0.040% are representative

of reactive aggregates. In the literature, these procedures were found to be effective

in correctly predicting the reactivity of aggregates.

Results indicate that using a 26-week expansion limit of 0.040% results in the

same aggregate classification as the standard C 1293 test. Category A, B, and C

aggregates were all found to be reactive, Category D aggregate was found to be

innocuous, E2-IA and E6-IN of Category E were found to be innocuous, and E4-NV

and E8-NM of Category E were found to be reactive. These are the same

conclusions obtained using the standard C 1293 procedures. Basically, storing the

concrete prisms in a 1N NaOH solution at 380C resulted in the same results but in a

shorter time (26-weeks). This is illustrated in Table 10.12.

It should be noted however, that the 26-week expansions of E2-IA and E6-IN

were respectively 0.036% and 0.038% both of which are very close to the 0.040%

limit and should be considered potentially reactive according to these procedures. In

addition, several aggregates were characterized as highly reactive while they were

showing as slowly reactive with the standard C 1293 (Figure 10.12). These

aggregates included E4-NV and E8-NM. As a result, these procedures were deemed

to be effective in detecting reactive aggregates but might be too severe for some

aggregates such E2-IA and E6-IN and might be over conservative with other

aggregates. A plot comparing these procedures to the standard C 1293 is included in

Figure 10.12 which shows a better distribution around the 450 line than the previous

results generated by storing concrete prisms in 1N NaOH solution at 800C.

233

Table 10.12: Summary of Generated Results: ASTM C 1293 vs 1N NaOH at 380C Using Respectively

0.040% at one-year and 0.040% at 26-week as Failure Criteria

Field

Performance

100% R.H. 380C

Standarda

1N NaOH 800C

Modifiedb

A1-WY Reactive Reactive Reactive A2-WY Reactive Reactive Reactive A3-ID Reactive Reactive Reactive A4-ID Reactive Reactive Reactive

A5-NM Reactive Reactive Reactive A6-NM Reactive Reactive Reactive A7-NC Reactive Reactive Reactive A8-VA Reactive Reactive Reactive A9-NE Reactive Reactive Reactive A10-PA Reactive Reactive Reactive B1-MD Reactive Reactive Reactive B2-MD Reactive Reactive Reactive B4-VA Reactive Reactive Reactive C1-SD Reactive Reactive Reactive C2-SD Reactive Reactive Reactive D1-IL Innocuous Innocuous Innocuous E2-Ia Innocuous Innocuous Innocuous

E3-NV Reactive Reactive Reactive E4-NV Reactive Reactive Reactive E6-IN Innocuous Innocuous Innocuous

E7-NM Reactive Reactive Reactive E8-NM Reactive Reactive Reactive

a = ASTM C 1293 failure criterion is 0.040% at one year b = Failure criterion is 0.06% at 1 weeks

Shaded area indicate aggregates with discrepancies (No discrepancies were noted)

234

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0.32

0.36

0.00 0.04 0.08 0.12 0.16 0.20 0.24 0.28 0.32 0.36

ASTM C 1293 1-Year Expansions, %

4-w

eek

Exp

ansi

on, %

(1

N a

t 80-

deg.

)

ASTM C 1293

Failure Criterion

Modified C 1293 Failure

Criterion

Storing concrete prisms in 1N NaOH solution at 380C resulted in aggregate

classifications that are comparable to ASTM C 1293 and that correlate well with the

field performance of all aggregates investigated; however, aggregates were shown to

be more reactive when evaluated using these procedures than when tested using C

1293.

Figure 10.12: Comparison Between the Standard C 1293 procedures and Modified C 1293 Storing Prisms in 1N NaOH at

380C

235

10.4 MODIFIED C 1293: PRISMS STORED OVER WATER, AT 100% R.H. AND 600C

These procedures are identical to the standard C 1293 except that the containers

are stored at 600C instead of 380C. These procedures are expected to produce

comparable results in a shorter period of time. Mixture proportions for these tests are

the same as the standard C 1293 and are listed in Table 7.12. Results of these

procedures are included in Tables 10.13 through 10.15 and Figures 10.13 through

10.15.

Table 10.13: Expansions of Category A Aggregate Concrete Prisms Stored

Over Water, at 100% R.H., and 600C Expansion, %

Time A1-WY A2-WY A3-ID A4-ID A5-NM A6-NM A7-NC A8-VA A9-NE A10-PA1-week 0.021 0.027 0.019 0.082 0.012 0.082 0.029 0.009 0.005 0.026 2-week 0.038 0.038 0.028 0.224 0.021 0.233 0.048 0.017 0.019 0.037 4-week 0.050 0.062 0.043 0.408 0.035 0.377 0.062 0.020 0.022 0.039 8-week 0.065 0.077 0.050 0.436 0.046 0.397 0.071 0.035 0.029 0.039

13-week 0.072 0.083 0.061 0.479 0.054 0.440 0.088 0.046 0.042 0.046

Table 10.14: Expansions of Category B, C, & D Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C

Expansion, % Time B1-MD B2-MD B4-VA C1-SD C2-SD D2-IL

1-week 0.005 0.008 0.009 0.011 0.014 0.010 2-week 0.011 0.015 0.018 0.029 0.016 0.011 4-week 0.019 0.020 0.027 0.040 0.029 0.012 8-week 0.033 0.034 0.034 0.058 0.050 0.017 13-week 0.041 0.045 0.043 0.065 0.059 0.021

236

Table 10.15: Expansions of Category E Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C

Expansion, % Time E2-IA E3-NV E4-NV E6-IN E7-NM E8-NM

1-week 0.016 0.010 0.019 0.012 0.015 0.027 2-week 0.016 0.021 0.023 0.018 0.027 0.034 4-week 0.023 0.037 0.034 0.020 0.042 0.040 8-week 0.024 0.051 0.045 0.024 0.051 0.048 13-week 0.028 0.062 0.059 0.029 0.063 0.054

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0 2 4 6 8 10 12 14

Time, Weeks

Exp

ansi

on, %

A1-WYA2-WYA3-IDA4-IDA5-NMA6-NMA7-NCA8-VAA9-NEA10-PA

Figure 10.13: Expansions of Category A Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C

237

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0 2 4 6 8 10 12 14

Time, Weeks

Exp

ansi

on, %

B1-MDB2-MDB4-VAC1-SDC2-SDD2-IL

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0 2 4 6 8 10 12 14

Time, Weeks

Exp

ansi

on, %

E2-IAE3-NVE4-NVE6-INE7-NME8-NM

Figure 10.14: Expansions of Category B, C, & D Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C

Figure 10.15: Expansions of Category E Aggregate Concrete Prisms Stored Over Water, at 100% R.H., and 600C

238

A proposed expansion limit of 0.040% after 3-months (13-weeks) of testing was

used to differentiate between reactive and innocuous aggregates. This limit was

proposed by researchers in the literature and was found to be effective with all types

of aggregates.

Category A, B, and C aggregates were all found to be reactive, Category D

aggregate was found to be innocuous, E2-IA and E6-IN of Category E were found to

be innocuous, and the E4-NV and E8-NM of Category E were found to be reactive.

These are the same conclusions obtained using the standard C 1293 procedures. Thus

these procedures generated results similar to the C 1293 procedures but in a much

shorter period of time (3 months). This is illustrated in Table 10.16.

A plot comparing these procedures to the standard C 1293 is included in Figure

10.16 where it can be noted that both testing procedures resulted in almost identical

results with an R2 value of 0.98. Thus, running the same procedures as C 1293 but

increasing the storage temperature to 600C resulted in identical results but in a much

shorter, 3 months, period of time.

239

Table 10.16: Summary of Generated Results: ASTM C 1293 vs C 1293 at 600C Using Respectively

0.040% at one-year and 0.040% at 13-week (3-months) as Failure Criteria

Field

Performance

100% R.H. 380C

Standarda

1N NaOH 800C

Modifiedb

A1-WY Reactive Reactive Reactive A2-WY Reactive Reactive Reactive A3-ID Reactive Reactive Reactive A4-ID Reactive Reactive Reactive

A5-NM Reactive Reactive Reactive A6-NM Reactive Reactive Reactive A7-NC Reactive Reactive Reactive A8-VA Reactive Reactive Reactive A9-NE Reactive Reactive Reactive A10-PA Reactive Reactive Reactive B1-MD Reactive Reactive Reactive B2-MD Reactive Reactive Reactive B4-VA Reactive Reactive Reactive C1-SD Reactive Reactive Reactive C2-SD Reactive Reactive Reactive D1-IL Innocuous Innocuous Innocuous E2-Ia Innocuous Innocuous Innocuous

E3-NV Reactive Reactive Reactive E4-NV Reactive Reactive Reactive E6-IN Innocuous Innocuous Innocuous

E7-NM Reactive Reactive Reactive E8-NM Reactive Reactive Reactive

a = ASTM C 1293 failure criterion is 0.040% at one year b = Failure criterion is 0.06% at 1 weeks

Shaded area indicate aggregates with discrepancies (No discrepancies were noted)

240

R2 = 0.9808

0.000.040.080.120.160.200.240.280.320.360.400.440.480.52

0.00 0.04 0.08 0.12 0.16 0.20 0.24 0.28 0.32 0.36 0.40 0.44 0.48 0.52

Standard C 1293 1-Year Expansions, %

13-w

eek

Exp

ansi

on, %

(C

129

3 at

60-

deg.

)

ASTM C 1293

Failure Criterion

Modified C 1293 Failure Criterion

Figure 10.16: Comparison Between the Standard C 1293 procedures and Modified C 1293 at 600C

241

10.5 SUMMARY: STANDARD AND MODIFIED C 1293 TESTING PROCEDURES

A summary of the results generated with the C 1293 procedures and its

modifications is included in Table 10.19. Tables 10.17 and 10.18 include a summary

of the expansion limit criteria used with each of the investigated testing procedures.

Table 10.17: Expansion Limits for the Different C 1293 Procedures Testing Procedure Length of Testing Expansion Limit Criteria

Over Water, 100% R.H., 380C 52 weeks (one year) 0.040% Over Water, 100% R.H., 600C 13 weeks (3 months) 0.040% In 1N NaOH Solution, 380C 26 weeks (6 months) 0.040% In 1N NaOH Solution, 800C 4 weeks 0.040%

Table 10.18: Aggregate’s Reactivity Classification for the Different C 1293 Procedures

Testing Procedure Length of Testing

Slowly Reactive

%

Highly Reactive

% Over Water, 100% R.H., 380C 52 weeks (one-year) 0.040-0.070 > 0.070 Over Water, 100% R.H., 600C 13 weeks (3 months) 0.040-0.070 > 0.070 In 1N NaOH Solution, 380C 26 weeks (6 months) 0.040-0.070 > 0.070 In 1N NaOH Solution, 800C 4 weeks 0.040-0.070 > 0.070

242

Table 10.19: Summary Results of the Different C 1293 Procedures 100% R.H.

380C Standard

100% R.H

600C

1N NaOH

380C

1N NaOH

800C A1-WY H.R. (0.073%) H.R. (0.072%) S.R. (0.034%) S.R. (0.037%) A2-WY H.R. (0.107%) H.R. (0.072%) H.R. (0.092%) H.R. (0.151%) A3-ID S.R. (0.058%) S.R. (0.061%) H.R. (0.242% H.R. (0.159%) A4-ID H.R. (0.379%) H.R. (0.467%) H.R. (0.242%) H.R. (0.318%)

A5-NM S.R. (0.084%) S.R. (0.054%) H.R. (0.172%) H.R. (0.099) A6-NM H.R. (0.411%) H.R. (0.427%) H.R. (0.297%) H.R. (0.332%) A7-NC H.R. (0.085%) H.R. (0.088%) S.R. (0.066%) H.R. (0.170%) A8-VA S.R. (0.047%) S.R. (0.046%) S.R. (0.066%) H.R. (0.118%) A9-NE S.R. (0.051%) S.R. (0.042%) S.R. (0.069%) H.R. (0.209%) A10-PA S.R. (0.043%) S.R. (0.041%) S.R. (0.063%) H.R. (0.159%) B1-MD S.R. (0.040%) S.R. (0.041%) S.R. (0.045%) S.R. (0.064%) B2-MD S.R. (0.046%) S.R. (0.045%) S.R. (0.071%) H.R. (0.141%) B4-VA S.R. (0.040%) S.R. (0.043%) S.R. (0.045%) H.R. (0.097%) C1-SD S.R. (0.063%) S.R. (0.065%) S.R. (0.064%) H.R. (0.092%) C2-SD S.R. (0.053) S.R. (0.059%) S.R. (0.052%) H.R. (0.148%) D1-IL Innocuous

(0.022%) Innocuous (0.021%)

Innocuous (0.025%)

Innocuous (0.006%)

E2-Ia Innocuous (0.025%)

Innocuous (0.024%)

Innocuous (0.036%)

H.R. (0.207%)

E3-NV S.R. (0.058%) S.R. (0.062%) Innocuous S.R. (0.063%) E4-NV S.R. (0.060%) S.R. (0.059%) H.R. (0.161%) H.R. (0.189%) E6-IN Innocuous

(0.022%) Innocuous (0.029%)

S.R. (0.038%)

S.R. (0.068%)

E7-NM S.R. (0.063%) S.R. (0.063%) Innocuous H.R. (0.092%) E8-NM S.R. (0.064%) S.R. (0.044%) H.R. (0.145%) H.R. (0.176%)

H.R. = Highly Reactive ; S.R. = Slowly Reactive Note1: The numbers in Parenthesis are the expansions at the specified length of

testing in Table 12.3 Note 2: Shaded area = Results that do not correlate with standard C 1293

Expansions that correlated perfectly with field performance

243

CHAPTER ELEVEN

INVESTIGATION OF MITIGATION ALTERNATIVES USING ASTM C 1260

11.1 INTRODUCTION

ASTM C 1260 was used to evaluate the effects of Class C fly ash, Class F fly ash,

silica fume, granulated slag, calcined clay, lithium nitrate (LiNO3), air content,

permeability, and cement alkali content on the ASR reactivity of selected aggregates.

Six aggregates were chosen to conduct these investigations: A4-ID (highly reactive C

1260 and C 1293), A6-NM (Highly Reactive C 1260 and C 1293), A2-WY

(moderately reactive C 1260 and C 1293), C2-SD (slowly reactive C 1260 and C

1293), B4-VA (Slowly Reactive C 1260 and C 1293), and E2-IA (Highly Reactive C

1260 and Innocuous C 1293). The following is a presentation and a discussion of

results generated using C 1260.

11.2 EFFECT OF CLASS C FLY ASH USING C 1260

In order to investigate the effect of Class C fly ash on the expansions due to ASR,

three levels of cement replacement were investigated namely, 20, 27.5, and 35%. The

six aggregates mentioned above were used to conduct the different mixtures listed in

Table 7.3. Results for these procedures are illustrated in Table 11.1 and Figures 11.1

through 11.6. A comparison of the 14-day expansions of the various replacement

levels is shown in Figure 11.7.

244

Table 11.1: C 1260 Expansions Using Class C Fly Ash

Aggregate ID

Class C Fly Ash

Content

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

A2-WY A2-WY 20% 0.17 0.19 0.23 0.24 0.29 0.32 A2-WY 27.5% 0.07 0.10 0.14 0.16 0.21 0.24 A2-WY 35% 0.03 0.05 0.08 0.10 0.14 0.17

A4-ID A4-ID 20% 0.22 0.29 0.37 0.41 0.51 0.58 A4-ID 27.5% 0.07 0.12 0.19 0.22 0.31 0.37 A4-ID 35% 0.03 0.06 0.11 0.14 0.21 0.26

A6-NM A6-NM 20% 0.21 0.31 0.43 0.49 0.61 0.72 A6-NM 27.5% 0.08 0.15 0.24 0.29 0.39 0.47 A6-NM 35% 0.03 0.08 0.13 0.20 0.29 0.36

BA-VA BA-VA 20% 0.02 0.05 0.10 0.14 0.20 0.25 BA-VA 27.5% 0.03 0.04 0.06 0.08 0.12 0.15 BA-VA 35% 0.02 0.03 0.05 0.06 0.08 0.10

C2-SD C2-SD 20% 0.05 0.10 0.14 0.18 0.24 0.30 C2-SD 27.5% 0.04 0.05 0.08 0.10 0.14 0.18 C2-SD 35% 0.02 0.04 0.06 0.07 0.09 0.12

E2-IA E2-IA 20% 0.11 0.20 0.33 0.36 0.47 0.53 E2-IA 27.5% 0.02 0.11 0.20 0.22 0.29 0.35 E2-IA 35% 0.01 0.08 0.09 0.11 0.12 0.15

245

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A2-WY-FAC 0%

A2-WY-FAC 20%A2-WY-FAC 27.5%A2-WY-FAC 35%

0.000.100.200.300.400.500.600.700.800.901.00

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A4-ID-FAC 0%

A4-ID-FAC 20%A4-ID-FAC 27.5%A4-ID-FAC 35%

Figure 11.1: Effect of Class C Fly Ash on C 1260 Expansions of Aggregate A2-WY

Figure 11.2: Effect of Class C Fly Ash on C 1260 Expansions of Aggregate A4-ID

246

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A6-NM-FAC 0%

A6-NM-FAC 20%A6-NM-FAC 27.5%A6-NM-FAC 35%

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

B4-VA-FAC 0%B4-VA-FAC 20%B4-VA-FAC 27.5%B4-VA-FAC 35%

Figure 11.3: Effect of Class C Fly Ash on C 1260 Expansions of Aggregate A6-NM

Figure 11.4: Effect of Class C Fly Ash on C 1260 Expansions of Aggregate B4-VA

247

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % C2-SD-FAC 0%

C2-SD-FAC 20%C2-SD-FAC 27.5%C2-SD-FAC 35%

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % E2-IA-FAC 0%

E2-IA-FAC 20%E2-IA-FAC 27.5%E2-IA-FAC 35%

Figure 11.5: Effect of Class C Fly Ash on C 1260 Expansions of Aggregate C2-SD

Figure 11.6: Effect of Class C Fly Ash on C 1260 Expansions of Aggregate E2-IA

248

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

A6-NM A4-ID A2-WY C2-SD B4-VA E2-IA

Investigated Aggregate

14-D

ay E

xpan

sion

, %

0% Class C Fly Ash20% Class C Fly Ash27.5% Class C Fly Ash35% Class C Fly Ash

From these results, it can be noticed that the expansions decreased as the levels of

replacement of cement with Class C fly ash increased. The more Class C fly ash in

the mixture the less expansion the aggregates were showing. Thirty-five percent

Class C fly ash was needed to reduce the expansions of the slowly reactive (C2-SD

and B4-VA) aggregates below 0.10%. Thirty-five percent Class C fly ash reduced

the 14-day expansions of the highly reactive aggregates A6-NM, A4-ID, and A2-WY

by an average of 80% but was not enough to reduce them below 0.10%. These results

are illustrated in Table 11.2. As a result, it was concluded that replacing 35% of the

weight of cement with Class C fly ash is effective with slowly reactive aggregates

but not highly reactive aggregates. Class C fly ash can be used with highly reactive

aggregates to reduce the expansions caused by ASR; however, it is not capable of

reducing the expansions to levels that are considered safe and innocuous.

Figure 11.7: Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Class C Fly Ash Replacement

249

Table 11.2: Effect of Class C Fly Ash on the 14-Day C 1260 Expansions

Aggregate ID

C 1260 14-Day

Expansion

C 1260 Classification

Class C Fly Ash Replacement by Weight of Cement 20% 27.5% 35%

A6-NM 0.91% H.R. H.R. H.R. H.R. A4-ID 0.79% H.R. H.R. H.R. S.R.

A2-WY 0.29% H.R. H.R. H.R. S.R. C2-SD 0.17% S.R. S.R. S.R. Innocuous B4-VA 0.15% S.R. S.R. Innocuous Innocuous E2-IA 0.42% H.R. H.R. H.R. S.R.

H.R. = Highly Reactive = C 1260 14-day expansion > 0.20% S.R. = Slowly Reactive = 0.10% < C 1260 14-day expansion < 0.20%

Innocuous = C 1260 14-day expansion < 0.10%

11.3 EFFECT OF CLASS F FLY ASH USING C 1260

In order to investigate the effect of Class F fly ash on the expansions due to ASR,

two levels of cement replacement were investigated namely, 15 and 25%. The six

aggregates mentioned above were used to conduct the various mixtures listed in

Table 7.4. Results for these procedures are illustrated in Table 11.3 and Figures 11.8

through 11.12. A comparison of the 14-day expansions of the various replacement

levels is shown in Figure 11.13.

250

Table 11.3: C 1260 Expansions Using Class F Fly Ash

Aggregate ID

Class F Fly Ash

Content

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

A2-WY A2-WY 15% 0.06 0.12 0.16 0.18 0.24 0.28 A2-WY 20% 0.01 0.02 0.03 0.05 0.10 0.14

A4-ID A4-ID 15% 0.10 0.17 0.24 0.29 0.40 0.45 A4-ID 20% 0.02 0.03 0.07 0.10 0.17 0.22

A6-NM A6-NM 15% 0.11 0.17 0.28 0.32 0.43 0.52 A6-NM 20% 0.01 0.03 0.09 0.12 0.20 0.27

B4-VA B4-VA 15% 0.02 0.02 0.05 0.07 0.11 0.16 B4-VA 20% 0.01 0.01 0.02 0.03 0.04 0.06

C2-SD C2-SD 15% 0.03 0.06 0.10 0.13 0.18 0.23 C2-SD 20% 0.01 0.02 0.03 0.04 0.06 0.09

E2-IA E2-IA 15% 0.05 0.11 0.18 0.25 0.31 0.36 E2-IA 20% 0.01 0.02 0.03 0.05 0.08 0.10

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A2-WY-FAF 0%

A2-WY-FAF 15%A2-WY-FAF 25%

Figure 11.8: Effect of Class F Fly Ash on C 1260 Expansions of Aggregate A2-WY

251

0.000.100.200.300.400.500.600.700.800.901.001.10

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A4-ID-FAF 0%

A4-ID-FAF 15%A4-ID-FAF 25%

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A6-NM-FAF 0%

A6-NM-FAF 15%A6-NM-FAF 25%

Figure 11.9: Effect of Class F Fly Ash on C 1260 Expansions of Aggregate A4-ID

Figure 11.10: Effect of Class F Fly Ash on C 1260 Expansions of Aggregate A6-NM

252

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % B4-VA-FAF 0%

B4-VA-FAF 15%B4-VA-FAF 25%

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % C2-SD-FAF 0%

C2-SD-FAF 15%C2-SD-FAF 25%

Figure 11.11: Effect of Class F Fly Ash on C 1260 Expansions of Aggregate B4-VA

Figure 11.12: Effect of Class F Fly Ash on C 1260 Expansions of Aggregate C2-SD

253

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % E2-IA-FAF 0%

E2-IA-FAF 15%E2-IA-FAF 25%

0.000.100.200.300.400.50

0.600.700.800.901.00

A6-NM A4-ID A2-WY C2-SD B4-VA E2-IA

Investigated Aggregate

14-D

ay E

xpan

sion

, %

0% Class F Fly Ash15% Class F Fly Ash25% Class F Fly Ash

Figure 11.14: Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Class F Fly Ash Replacement

Figure 11.13: Effect of Class F Fly Ash on C 1260 Expansions of Aggregate E2-IA

254

As the percentage of replacing cement with Class F fly ash increased the

expansions of the six aggregates decreased. Fifteen percent replacement of cement

with Class F fly ash was not effective in decreasing the 14-day expansions below

0.10% of any of the aggregates. Twenty-five percent Class F fly ash was needed to

decrease the 14-day expansions of A4-ID, A2-WY, C2-SD, and B4-VA below

0.10%. Twenty-five percent Class F fly ash was not effective in decreasing the 14-

day expansions of the highly reactive aggregate A6-NM below 0.10%. A6-NM,

when used with 25% Class F fly ash, had 14-day expansions of 0.119%, which is

about 87% lower than the expansions shown by this aggregate without fly ash

replacement (0.913%). These observations are summarized in Table 11.4

Table 11.4: Effect of Class F Fly Ash on the 14-Day C 1260 Expansions

Aggregate ID

C 1260 14-Day

Expansion C 1260

Classification

Class F Fly Ash Replacement by Weight of

Cement 15% 25%

A6-NM 0.91% H.R. H.R. S.R. A4-ID 0.79% H.R. H.R. S.R.

A2-WY 0.29% H.R. S.R. Innocuous C2-SD 0.17% S.R. S.R. Innocuous B4-VA 0.15% S.R. Innocuous Innocuous E2-IA 0.42% H.R. S.R. Innocuous

H.R. = Highly Reactive = C 1260 14-day expansion > 0.20% S.R. = Slowly Reactive = 0.10% < C 1260 14-day expansion < 0.20%

Innocuous = C 1260 14-day expansion < 0.10%

255

11.4 EFFECT OF SILICA FUME USING C 1260

In order to investigate the effect of silica fume on the expansions due to ASR, two

levels of cement replacement were investigated namely, 5 and 10%. The six

aggregates mentioned above were used to conduct the various mixtures listed in

Table 7.5. Results for these procedures are illustrated in Table 11.5 and Figures

11.15 through 11.20. A comparison of the 14-day expansions of the various

replacement levels is shown in Figure 11.21.

Table 11.5: C 1260 Expansions Using Silica Fume

Aggregate ID

Silica Fume

Content

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

A2-WY A2-WY 5% 0.14 0.25 0.32 0.35 0.38 0.41 A2-WY 10% 0.02 0.05 0.10 0.13 0.20 0.26

A4-ID A4-ID 5% 0.14 0.30 0.46 0.53 0.66 0.74 A4-ID 10% 0.02 0.04 0.10 0.13 0.22 0.29

A6-NM A6-NM 5% 0.21 0.37 0.56 0.67 0.89 1.03 A6-NM 10% 0.03 0.06 0.14 0.19 0.30 0.39

B4-VA B4-VA 5% 0.02 0.05 0.09 0.13 0.21 0.27 B4-VA 10% 0.01 0.02 0.04 0.06 0.11 0.15

C2-SD C2-SD 5% 0.03 0.06 0.11 0.15 0.21 0.27 C2-SD 10% 0.00 0.02 0.05 0.08 0.13 0.17

E2-IA E2-IA 5% 0.11 0.19 0.25 0.31 0.39 0.47 E2-IA 10% 0.03 0.07 0.09 0.14 0.19 0.23

256

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A2-WY-SF 0%

A2-WY-SF 5%A2-WY-SF 10%

0.000.100.200.300.400.500.600.700.800.901.001.10

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A4-ID-SF 0%

A4-ID-SF 5%A4-ID-SF 10%

Figure 11.15: Effect of Silica Fume on C 1260 Expansions of Aggregate A2-WY

Figure 11.16: Effect of Silica Fume on C 1260 Expansions of Aggregate A4-ID

257

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A6-NM-SF 0%

A6-NM-SF 5%A6-NM-SF 10%

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Time, Days

Exp

ansi

on, % B4-VA-SF 0%

B4-VA-SF 5%B4-VA-SF 10%

Figure 11.17: Effect of Silica Fume on C 1260 Expansions of Aggregate A6-NM

Figure 11.18: Effect of Silica Fume on C 1260 Expansions of Aggregate B4-VA

258

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % C2-SD-SF 0%

C2-SD-SF 5%C2-SD-SF 10%

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0 10 20 30

Time, Days

Exp

ansi

on, % E2-IA-SF 0%

E2-IA-SF 5%E2-IA-SF 10%

Figure 11.19: Effect of Silica Fume on C 1260 Expansions of Aggregate C2-SD

Figure 11.20: Effect of Silica Fume on C 1260 Expansions of Aggregate E2-IA

259

0.000.100.200.300.400.500.600.700.800.901.00

A6-NM A4-ID A2-WY C2-SD B4-VA E2-IA

Investigated Aggregate

14-D

ay E

xpan

sion

, %0% Silica Fume5% Silica Fume10% Silica Fume

Expansions decreased as the silica fume content increased. Replacing 10% by

weight of the cement with silica fume was needed to decrease the 14-day expansions

of the slowly reactive aggregates, B4-VA and C2-SD, below 0.10%. Ten percent

replacement of cement with silica fume decreased the 14-day expansions of the

highly reactive aggregates by an average of 70%. Still, these expansions were higher

than 0.10% and were considered excessive. The use of 5% silica fume caused a

decrease in the expansions but was not effective in decreasing the 14-day expansions

below 0.10% for any of the investigated aggregates. These observations are

summarized in Table 11.6.

Figure 11.21: Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Silica Fume Replacement

260

Table 11.6: Effect of Silica Fume on the 14-Day C 1260 Expansions

Aggregate ID

C 1260 14-Day

Expansion C 1260

Classification

Silica Fume Replacement by Weight of

Cement 5% 10%

A6-NM 0.91% H.R. H.R. S.R. A4-ID 0.79% H.R. H.R. S.R.

A2-WY 0.29% H.R. H.R. S.R. C2-SD 0.17% S.R. S.R. Innocuous B4-VA 0.15% S.R. S.R. Innocuous E2-IA 0.42% H.R. H.R. S.R.

H.R. = Highly Reactive = C 1260 14-day expansion > 0.20% S.R. = Slowly Reactive = 0.10% < C 1260 14-day expansion < 0.20%

Innocuous = C 1260 14-day expansion < 0.10%

11.5 EFFECT OF GRANULATED SLAG USING C 1260

In order to investigate the effect of granulated slag on the expansions due to ASR,

three levels of cement replacement were investigated namely, 40, 55, and 70%. The

six aggregates mentioned above were used to conduct the different mixtures listed in

Table 7.6. Results for these procedures are illustrated in Table 11.7 and Figures

11.22 through 11.27. A comparison of the 14-day expansions of the various

replacement levels is shown in Figure 11.28.

261

Table 11.7: C 1260 Expansions Using Granulated Slag

Aggregate ID

Granulated Slag

Content

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

A2-WY A2-WY 40% 0.07 0.12 0.17 0.19 0.24 0.31 A2-WY 55% 0.00 0.02 0.05 0.07 0.11 0.16 A2-WY 70% -0.01 0.00 0.01 0.01 0.03 0.06

A4-ID A4-ID 40% 0.07 0.15 0.22 0.33 0.38 0.44 A4-ID 55% 0.02 0.03 0.05 0.09 0.17 0.21 A4-ID 70% 0.01 0.01 0.02 0.03 0.05 0.07

A6-NM A6-NM 40% 0.09 0.17 0.27 0.32 0.45 0.60 A6-NM 55% 0.01 0.05 0.11 0.15 0.23 0.30 A6-NM 70% -0.01 0.00 0.01 0.02 0.06 0.12

B4-VA B4-VA 40% 0.01 0.02 0.05 0.06 0.10 0.14 B4-VA 55% 0.01 0.01 0.02 0.02 0.04 0.05 B4-VA 70% 0.00 0.00 0.00 0.01 0.01 0.02

C2-SD C2-SD 40% 0.04 0.07 0.10 0.14 0.20 0.25 C2-SD 55% 0.02 0.03 0.04 0.07 0.10 0.17 C2-SD 70% -0.01 0.00 0.00 0.01 0.03 0.04

E2-IA E2-IA 40% 0.07 0.10 0.15 0.20 0.23 0.29 E2-IA 55% 0.01 0.03 0.06 0.08 0.09 0.12 E2-IA 70% 0.00 0.01 0.02 0.02 0.03 0.05

262

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A2-WY-SLAG 0%

A2-WY-SLAG 40%A2-WY-SLAG 55%A2-WY-SLAG 70%

0.000.100.200.300.400.500.600.700.800.901.001.10

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A4-ID-SLAG 0%

A4-ID-SLAG 40%A4-ID-SLAG 55%A4-ID-SLAG 70%

Figure 11.22: Effect of Slag on C 1260 Expansions of Aggregate A2-WY

Figure 11.23: Effect of Slag on C 1260 Expansions of Aggregate A4-ID

263

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A6-NM-SLAG 0%

A6-NM-SLAG 40%A6-NM-SLAG 55%A6-NM-SLAG 70%

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % B4-VA-SLAG 0%

B4-VA-SLAG 40%B4-VA-SLAG 55%B4-VA-SLAG 70%

Figure 11.24: Effect of Slag on C 1260 Expansions of Aggregate A6-NM

Figure 11.25: Effect of Slag on C 1260 Expansions of Aggregate B4-VA

264

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % C2-SD-SLAG 0%

C2-SD-SLAG 40%C2-SD-SLAG 55%C2-SD-SLAG 70%

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0 10 20 30

Time, Days

Exp

ansi

on, % E2-IA-SLAG 0%

E2-IA-SLAG 40%E2-IA-SLAG 55%E2-IA-SLAG 70%

Figure 11.26: Effect of Slag on C 1260 Expansions of Aggregate C2-SD

Figure 11.27: Effect of Slag on C 1260 Expansions of Aggregate E2-IA

265

0.000.100.200.300.400.500.600.700.800.901.00

A6-NM A4-ID A2-WY C2-SD B4-VA E2-IA

Investigated Aggregate

14-D

ay E

xpan

sion

, %0% Slag40% Slag55% Slag70%Slag

An examination of these results led to the following observations:

1. As the amount of slag in the mixture increased the expansions of the six

aggregates decreased.

2. Replacing 40% of the weight of cement with slag resulted in decreasing the 14-

day expansion of B4-VA (Slowly Reactive) below 0.10%. However, 40% slag

was not effective with the other slowly reactive aggregate C2-SD that showed a

14-day expansion of 0.14% (a 21% decrease). The other aggregates A2-WY

(H.R.), A4-ID (H.R.), A6-NM (H.R.), and E2-IA (H.R.) showed 14-day

expansions higher than 0.10% at this level of slag corresponding to an average

decrease of 55%.

3. Using 55% slag in the mixtures was effective in decreasing the 14-day

expansions of A4-ID (H.R.), A2-WY (H.R.), E2-IA (H.R.), B4-VA (S.R.), and

C2-SD (S.R.) below 0.10%. Fifty-five percent slag was not effective with the

Figure 11.28: Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Slag Replacement

266

highly reactive aggregates A6-NM, which showed 14-day expansions of 0.15%

(84% lower than the expansion of mortar bars with no slag).

4. Replacing 70% of the weight of cement with slag was enough to keep the 14-day

expansions of the six aggregates well below 0.10%.

5. The above observations are summarized in Table 11.8.

Table 11.8: Effect of Granulated Slag on the 14-Day C 1260 Expansions

Aggregate ID

C 1260 14-Day

Expansion

C 1260 Classification

Granulated Slag Replacement by Weight of Cement 40% 55% 70%

A6-NM 0.91% H.R. H.R. S.R. Innocuous A4-ID 0.79% H.R. H.R. Innocuous Innocuous

A2-WY 0.29% H.R. S.R. Innocuous Innocuous C2-SD 0.17% S.R. S.R. Innocuous Innocuous B4-VA 0.15% S.R. Innocuous Innocuous Innocuous E2-IA 0.42% H.R. S.R. Innocuous Innocuous

H.R. = Highly Reactive = C 1260 14-day expansion > 0.20% S.R. = Slowly Reactive = 0.10% < C 1260 14-day expansion < 0.20%

Innocuous = C 1260 14-day expansion < 0.10%

11.6 EFFECT OF CALCINED CLAY USING C 1260

In order to investigate the effect of calcined clay on the expansions due to ASR,

two levels of cement replacement were investigated namely, 17 and 25%. The six

aggregates mentioned above were used to conduct the various mixtures listed in

Table 7.9. Results for these procedures are illustrated in Table 11.9 and Figures

11.29 through 11.34. A comparison of the 14-day expansions of the various

replacement levels is shown in Figure 11.35.

267

Table 11.9: C 1260 Expansions Using Calcined Clay

Aggregate ID

Calcined Clay

Content

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

A2-WY A2-WY 17% 0.02 0.04 0.08 0.10 0.16 0.19 A2-WY 25% 0.00 0.01 0.01 0.02 0.02 0.03

A4-ID A4-ID 17% 0.01 0.03 0.07 0.13 0.20 0.24 A4-ID 25% 0.00 0.01 0.01 0.03 0.05 0.07

A6-NM A6-NM 17% 0.01 0.04 0.09 0.16 0.25 0.31 A6-NM 25% 0.00 0.00 0.01 0.02 0.04 0.07

B4-VA B4-VA 17% 0.00 0.01 0.01 0.02 0.03 0.05 B4-VA 25% 0.00 0.00 0.00 0.01 0.01 0.03

C2-SD C2-SD 17% 0.01 0.02 0.03 0.06 0.07 0.09 C2-SD 25% 0.00 0.01 0.01 0.02 0.03 0.04

E2-IA E2-IA 17% 0.01 0.03 0.07 0.10 0.12 0.18 E2-IA 25% 0.00 0.01 0.01 0.01 0.03 0.03

268

-0.050.000.050.100.150.200.250.300.350.40

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A2-WY-CC 0%

A2-WY-CC 17%A2-WY-CC 25%

0.000.100.200.300.400.500.600.700.800.901.001.10

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A4-ID-CC 0%

A4-ID-CC 17%A4-ID-CC 25%

Figure 11.29: Effect of Calcined Clay on C 1260 Expansions of Aggregate A2-WY

Figure 11.30: Effect of Calcined Clay on C 1260 Expansions of Aggregate A4-ID

269

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32

Time, Days

Expa

nsio

n, % A6-NM-CC 0%

A6-NM-CC 17%A6-NM-CC 25%

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % B4-VA-CC 0%

B4-VA-CC 17%B4-VA-CC 25%

Figure 11.31: Effect of Calcined Clay on C 1260 Expansions of Aggregate A6-NM

Figure 11.32: Effect of Calcined Clay on C 1260 Expansions of Aggregate B4-VA

270

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % C2-SD-CC 0%

C2-SD-CC 17%C2-SD-CC 25%

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % E2-IA-CC 0%

E2-IA-CC 17%E2-IA-CC 25%

Figure 11.33: Effect of Calcined Clay on C 1260 Expansions of Aggregate C2-SD

Figure 11.34: Effect of Calcined Clay on C 1260 Expansions of Aggregate E2-IA

271

0.000.100.200.300.400.500.600.700.800.901.00

A6-NM A4-ID A2-WY C2-SD B4-VA E2-IA

Investigated Aggregate

14-D

ay E

xpan

sion

, %0% Calcined Clay17% Calcined Clay25% Calcined Clay

In order to determine whether the remaining Category E aggregates react in a

comparable manner to the mitigation alternatives, calcined clay was used to replace

17 and 25% of the cement of mortar bars formed with Category E aggregates.

Results are presented in Table 11.10 and Figure 11.36.

Figure 11.35: Comparison of the 14-Day C 1260 Expansions for the Different Aggregates and Levels of Calcined Clay Replacement

272

Table 11.10: Category E C 1260 Expansions Using Calcined Clay

Aggregate ID

Calcined Clay

Content

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

E2-IAE2-IA 17% 0.01 0.03 0.07 0.10 0.12 0.18 E2-IA 25% 0.00 0.01 0.01 0.01 0.03 0.03

E4-NV E4-NV 17% 0.02 0.05 0.09 0.13 0.19 0.22 E4-NV 25% 0.01 0.02 0.02 0.02 0.03 0.04

E6-IN E6-IN 17% 0.01 0.05 0.09 0.11 0.15 0.20 E6-IN 25% 0.00 0.01 0.01 0.01 0.02 0.02

E8-NM E8-NM 17% 0.01 0.04 0.07 0.12 0.20 0.25 E8-NM 25% 0.01 0.01 0.02 0.02 0.03 0.04

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

E2-IA E4-NV-CC E6-IN E8-NM

Investigated Aggregate

14-D

ay E

xpan

sion

, %

0% Calcined Clay17% Calcined Clay25% Calcined Clay

Figure 11.36: Effect of Calcined Clay on the 14-Day C 1260 Expansions of Category E Aggregates

273

An examination of these results generated the following observations:

1. As noticed before, the expansion decreased as the amount of calcined clay in the

mixtures increased.

2. Using 17% calcined clay to replace cement by weight was effective in decreasing

the 14-day expansion of the slowly reactive aggregates, B4-VA and C2-SD, and

the highly reactive aggregates A2-WY and E2-IA below 0.10%. However, 17%

calcined clay was not effective with the highly reactive aggregates A4-ID and

A6-NM, both of which showed 14-day expansions higher than 0.10%. Fourteen-

day expansions of mortar bars made with 17% calcined clay were lower than the

expansions of mortar bar with no calcined clay. For A4-ID (H.R.) and A6-NM

(H.R.), the 14-day expansions were about 83% lower.

3. Replacing 25% of the weight of cement with calcined clay was effective in

decreasing the 14-day expansions of the six aggregates well below 0.10%.

4. Category E aggregates reacted in a similar manner to Category A aggregates.

5. The observations noted above are summarized in Table 11.11.

Table 11.11: Effect of Calcined Clay on the 14-Day C 1260 Expansions

Aggregate ID

C 1260 14-Day

Expansion C 1260

Classification

Calcined Clay Replacement by Weight of

Cement 17% 25%

A6-NM 0.91% H.R. S.R. Innocuous A4-ID 0.79% H.R. S.R. Innocuous

A2-WY 0.29% H.R. S.R. Innocuous C2-SD 0.17% S.R. Innocuous Innocuous B4-VA 0.15% S.R. Innocuous Innocuous E2-IA 0.42% H.R. S.R. Innocuous E4-NV 0.25% H.R. S.R. Innocuous E6-IN 0.25% H.R. S.R. Innocuous

E8-NM 0.36% H.R. S.R. Innocuous H.R. = Highly Reactive = C 1260 14-day expansion > 0.20% S.R. = Slowly Reactive = 0.10% < C 1260 14-day expansion < 0.20%

Innocuous = C 1260 14-day expansion < 0.10%

274

11.7 EFFECT OF AIR ENTRAINMENT USING C 1260

In order to investigate the effect of air entrainment on the expansions due to ASR,

two ranges of entrained air were investigated namely, between 2 and 4% labeled AE

4% and between 6 and 8% labeled AE 8%. In this section entrained air refers to total

air content reduced by the entrapped air content. The six aggregates mentioned above

were used to conduct the different mixtures listed in Table 7.8. Results for these

procedures are illustrated in Table 11.12 and Figures 11.37 through 11.42. A

comparison of the 14-day expansions of the different air levels is shown in Figure

11.43.

Table 11.12: C 1260 Expansions Using Air Entrainment

Aggregate ID

Air Entrainment

Content

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

A2-WY A2-WY 4% 0.06 0.10 0.12 0.13 0.15 0.16 A2-WY 8% 0.05 0.08 0.10 0.11 0.12 0.14

A4-ID A4-ID 4% 0.16 0.26 0.35 0.37 0.42 0.46 A4-ID 8% 0.15 0.24 0.33 0.36 0.40 0.44

A6-NM A6-NM 4% 0.21 0.28 0.44 0.48 0.54 0.59 A6-NM 8% 0.21 0.33 0.43 0.47 0.53 0.57

B4-VA B4-VA 4% 0.02 0.04 0.06 0.08 0.11 0.13 B4-VA 8% 0.02 0.04 0.07 0.08 0.11 0.13

C2-SD C2-SD 4% 0.04 0.07 0.10 0.12 0.15 0.18 C2-SD 8% 0.04 0.07 0.10 0.12 0.16 0.19

E2-IA E2-IA 4% 0.07 0.11 0.13 0.14 0.15 0.16 E2-IA 8% 0.06 0.09 0.1 0.12 0.14 0.15

275

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A2-WY-AE 0%

A2-WY-AE 4%

A2-WY-AE 8%

0.000.100.200.300.400.500.600.700.800.901.001.10

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A4-ID-AE 0%

A4-ID-AE 4%

A4-ID-AE 8%

Figure 11.37: Effect of Air Entrainment on C 1260 Expansions of Aggregate A2-WY

Figure 11.38: Effect of Air Entrainment on C 1260 Expansions of Aggregate A4-ID

276

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A6-NM-AE 0%

A6-NM-AE 4%

A6-NM-AE 8%

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % B4-VA-AE 0%

B4-VA-AE 4%B4-VA-AE 8%

Figure 11.39: Effect of Air Entrainment on C 1260 Expansions of Aggregate A6-NM

Figure 11.40: Effect of Air Entrainment on C 1260 Expansions of Aggregate B4-VA

277

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % C2-SD-AE 0%

C2-SD-AE 4%

C2-SD-AE 8%

0.00

0.10

0.20

0.30

0.40

0.50

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % E2-IA-AE 0%

E2-IA-AE 4%

E2-IA-AE 8%

Figure 11.41: Effect of Air Entrainment on C 1260 Expansions of Aggregate C2-SD

Figure 11.42: Effect of Air Entrainment on C 1260 Expansions of Aggregate E2-IA

278

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

A6-NM A4-ID A2-WY C2-SD B4-VA E2-IA

Investigated Aggregate

14-D

ay E

xpan

sion

, % 0% Air Entrained2-4% Air Entrained6-8% Air Entrained

An examination of these results generated the following observations:

1. Using between 2 and 4% entrained air (Total Air – Entrapped Air) in the

mixtures caused the 14-day expansions to decrease by 66% for A2-WY, 53% for

A4-ID, 48% for A6-NM, 44% for B4-VA, and 32% for C2-SD. However, the 14-

day expansions for the six aggregates were higher than 0.10%, with the exception

of B4-VA that showed a 14-day expansion of 0.081%. Table 11.13 summarizes

these observations.

2. Increasing the entrained air content from between 2 and 4% to between 6 and 8%

showed little benefit. Fourteen-day expansions of mortar bars with 4% entrained

air were comparable and very close to those with 8% entrained air. This is

probably caused by the increase in porosity that results from increasing the air

content. This means that the beneficial effects of air entrainment can be achieved

by using 2 to 4% air.

Figure 11.43: Comparison of the 14-Day C 1260 Expansions for the Different Entrained Air Levels

279

Table 11.13: Effect of Air Entrainment on the 14-Day C 1260 Expansions

Aggregate ID

C 1260 14-Day

Expansion C 1260

Classification

Calcined Clay Replacement by Weight of

Cement 17% 25%

A6-NM 0.91% H.R. H.R. H.R. A4-ID 0.79% H.R. H.R. H.R.

A2-WY 0.29% H.R. S.R. S.R. C2-SD 0.17% S.R. S.R. S.R. B4-VA 0.15% S.R. Innocuous Innocuous E2-IA 0.42% H.R. S.R. S.R.

H.R. = Highly Reactive = C 1260 14-day expansion > 0.20% S.R. = Slowly Reactive = 0.10% < C 1260 14-day expansion < 0.20%

Innocuous = C 1260 14-day expansion < 0.10%

11.8 EFFECT OF WATER-CEMENT RATIO USING C 1260 In order to investigate the effect water-cement ratio on the expansions due to

ASR, the water-cement ratio was varied between 0.35 and 0.65. The investigated

water-cement ratios were 0.35, 0.47, 0.55, and 0.65. The water-cement ratio was

varied by varying the amount of water in the mixture while keeping all other

constituents constant. Mixture proportions are listed in Table 7.10. Results for these

procedures are illustrated in Table 11.14 and Figures 11.44 through 11.48. A

comparison of the 14-day expansions of the various water-cement ratios is shown in

Figure 11.49.

280

Table 11.14: C 1260 Expansions Using Various Water-Cement Ratios

Aggregate ID

Water-Cement Ratio

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

A2-WY A2-WY 0.35 0.16 0.24 0.32 0.35 0.42 0.47 A2-WY 0.55 0.17 0.21 0.23 0.25 0.27 0.29 A2-WY 0.65 0.13 0.15 0.17 0.18 0.20 0.22

A4-ID A4-ID 0.35 0.64 0.88 1.04 1.11 1.22 1.29 A4-ID 0.55 0.52 0.68 0.80 0.84 0.91 0.96 A4-ID 0.65 0.36 0.48 0.56 0.60 0.65 0.69

A6-NM A6-NM 0.35 0.62 0.84 1.03 1.13 1.30 1.42 A6-NM 0.55 0.48 0.68 0.83 0.90 0.99 1.06 A6-NM 0.65 0.29 0.43 0.53 0.57 0.62 0.68

B4-VA B4-VA 0.35 0.03 0.06 0.12 0.17 0.26 0.36 B4-VA 0.55 0.03 0.06 0.10 0.13 0.17 0.23 B4-VA 0.65 0.03 0.06 0.09 0.11 0.15 0.20

C2-SD C2-SD 0.35 0.06 0.09 0.16 0.20 0.29 0.38 C2-SD 0.55 0.03 0.06 0.09 0.11 0.16 0.21 C2-SD 0.65 0.03 0.05 0.07 0.09 0.13 0.18

281

0.000.050.100.150.200.250.300.350.400.450.50

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A2-WY-W/C 0.35

A2-WY-W/C 0.47A2-WY-W/C 0.55A2-WY-W/C 0.65

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

A4-ID-W/C 0.35A4-ID-W/C 0.47A4-ID-W/C 0.55A4-ID-W/C 0.65

Figure 11.44: Effect of W/C on C 1260 Expansions of Aggregate A2-WY

Figure 11.45: Effect of W/C on C 1260 Expansions of Aggregate A4-ID

282

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

A6-NM-W/C 0.35A6-NM-W/C 0.47A6-NM-W/C 0.55A6-NM-W/C 0.65

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

BA-VA-W/C 0.35BA-VA-W/C 0.47BA-VA-W/C 0.55BA-VA-W/C 0.65

Figure 11.46: Effect of W/C on C 1260 Expansions of Aggregate A6-NM

Figure 11.47: Effect of W/C on C 1260 Expansions of Aggregate B4-VA

283

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

C2-SD-W/C 0.35C2-SD-W/C 0.47C2-SD-W/C 0.55C2-SD-W/C 0.65

0.00

0.20

0.40

0.60

0.80

1.00

1.20

A6-NM A4-ID A2-WY C2-SD B4-VA

Investigated Aggregate

14-D

ay E

xpan

sion

, %

W/C = 0.35W/C = 0.47W/C = 0.55W/C = 0.65

Figure 11.48: Effect of W/C on C 1260 Expansions of Aggregate C2-SD

Figure 11.49: Comparison of the 14-Day C 1260 Expansions for the Different Water-Cement Ratios

284

The investigated water-cement (W/C) ratios were 0.35, 0.47 (standard), 0.55, and

0.65. The W/C was changed by changing the water content of the mixture. The idea

was that by increasing the W/C, the permeability would increase and vice versa. By

examining the results it can be noticed that the expansions at a W/C of 0.35 for all

six aggregates were higher than the expansions at the other W/C ratios. Thus, as the

W/C decreased from 0.47 (standard C 1260 test requirement) to 0.35 the expansions

increased by 26% for A2-WY, 40% for A4-ID, 24% for A6-NM, 19% for B4-VA,

and 14% for C2-SD (about 25% on average). Even though the permeability was

decreased the expansion increased. This might be explained by the fact that as the

W/C is decreased to 0.35 the porosity decreases and becomes more compact and

uniform. Very little space is left for the gel to form. If the same amount of gel that

was formed at a W/C of 0.47 is formed at 0.35, the bars with W/C of 0.35 will

expand more. As a result, decreasing the permeability by decreasing the water-

cement ratio (water content) had a detrimental effect on the expansions caused by

ASR. Decreasing the W/C resulted in an increase in expansions.

As the water-cement ratio increased from 0.35 to 0.65, the expansions of the five

aggregates decreased. Mortar bars with a water-cement ratio of 0.35 showed the

highest expansions followed by the ones with water-cement ratio of 0.47, than the

ones with water-cement ratio of 0.55, and finally the ones with water-cement ratio of

0.65. It should be noted that all 14-day expansions for all six aggregates at all water-

cement ratios were well above 0.10%. As a result, it can be concluded that as the

water-cement ratio of the mortar bars increased from 0.35 to 0.65, their C 1260

expansions decreased.

285

11.9 EFFECT OF LITHIUM NITRATE (LiNO3) USING C 1260

In order to investigate the effect of LiNO3 on the expansions due to ASR, a

volume of the mixing water was replaced with a LiNO3 solution. The replaced

volume of water was equal to 85% of the volume of LiNO3 added. The dosages of

LiNO3 were as follows:

1. 3.5 liters of LiNO3 per 1 kg of Na2O in the mixture (21 g of LiNO3 for our

mixtures)

2. 4.6 liters of LiNO3 per 1 kg of Na2O in the mixture (28 g of LiNO3 for our

mixtures)

3. 10 liters of LiNO3 per 1 kg of Na2O in the mixture (60 g of LiNO3 for our

mixtures)

Mixture proportions are listed in Table 7.7. Results for these procedures are

illustrated in Table 11.15 and Figures 11.50 through 11.55. A comparison of the 14-

day expansions of the various lithium dosages is shown in Figure 11.56.

286

Table 11.15: C 1260 Expansions Using Different LiNO3 Dosages

Aggregate ID

Lithium Content

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

A2-WY A2-WY 21 g 0.02 0.04 0.07 0.09 0.15 0.18 A2-WY 28 g 0.01 0.03 0.05 0.07 0.13 0.17 A2-WY 60 g 0.00 0.01 0.02 0.02 0.05 0.08

A4-ID A4-ID 21 g 0.15 0.27 0.44 0.49 0.59 0.66 A4-ID 28 g 0.07 0.19 0.38 0.46 0.59 0.66 A4-ID 60 g 0.01 0.03 0.10 0.16 0.27 0.33

A6-NM A6-NM 21 g 0.17 0.31 0.45 0.55 0.73 0.83 A6-NM 28 g 0.11 0.26 0.43 0.55 0.77 0.88 A6-NM 60 g 0.02 0.08 0.20 0.28 0.42 0.47

B4-VA B4-VA 21 g 0.01 0.02 0.07 0.09 0.18 0.22 B4-VA 28 g 0.01 0.02 0.05 0.07 0.15 0.21 B4-VA 60 g 0.01 0.01 0.02 0.03 0.05 0.08

C2-SD C2-SD 21 g 0.02 0.05 0.10 0.15 0.23 0.28 C2-SD 28 g 0.02 0.04 0.06 0.10 0.17 0.21 C2-SD 60 g 0.00 0.01 0.02 0.03 0.05 0.07

E2-IA E2-IA 21 g 0.02 0.05 0.06 0.08 0.10 0.14 E2-IA 28 g 0.01 0.04 0.05 0.07 0.15 0.18 E2-IA 60 g 0.00 0.01 0.03 0.04 0.04 0.07

287

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A2-WY-Lithium 0g

A2-WY-Lithium21gA2-WY-Lithium28g

0.000.100.200.300.400.500.600.700.800.901.001.10

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A4-ID-Lithium 0 g

A4-ID-Lithium 21gA4-ID-Lithium 28gA4-ID-Litium 60g

Figure 11.50: Effect of LiNO3 on C 1260 Expansions of Aggregate A2-WY

Figure 11.51: Effect of LiNO3 on C 1260 Expansions of Aggregate A4-ID

288

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % A6-NM-Lithium 0 g

A6-NM-Lithium21gA6-NM-Lithium28g

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % B4-VA-Lithium 0 g

B4-VA-Lithium 21gB4-VA-Lithium 28gB4-VA-Litium 60g

Figure 11.52: Effect of LiNO3 on C 1260 Expansions of Aggregate A6-NM

Figure 11.53: Effect of LiNO3 on C 1260 Expansions of Aggregate B4-VA

289

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % C2-SD-Lithium 0 g

C2-SD-Lithium 21gC2-SD-Lithium 28gC2-SD-Litium 60g

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % E2-IA-Lithium 0 g

E2-IA-Lithium 21gE2-IA-Lithium 28gE2-IA-Litium 60g

Figure 11.54: Effect of LiNO3 on C 1260 Expansions of Aggregate C2-SD

Figure 11.55: Effect of LiNO3 on C 1260 Expansions of Aggregate E2-IA

290

0.000.100.200.300.400.500.600.700.800.901.00

A6-NM A4-ID A2-WY C2-SD B4-VA E2-IA

Investigated Aggregate

14-D

ay E

xpan

sion

, %0g LiNO321g LiNO328g LiNO360g LiNO3

It was suggested in the literature (Starks 1993, Mc Keen 1998) that ASTM C 1260

is not a suitable test for investigating the effect of LiNO3 on ASR because of the

leaching of LiNO3 from the mortar bars to the NaOH solution. Still the procedures

were performed. As can be seen from the results, expansions decreased as LiNO3

replaced part of the mixture water. Using 21g LiNO3 was effective in decreasing the

14-day expansions of only A2-WY below 0.10%. Twenty-eight grams of LiNO3 was

effective with A2-WY (H.R.), B4-VA (S.R.), and C2-SD (S.R.) but not A4-ID (H.R.)

and A6-NM (H.R.). Sixty grams of LiNO3 was also not effective with the highly

reactive A4-ID and A6-NM. These observations are summarized in Table 11.16.

It should be noted that as time progressed, the difference between the expansions

of mortar bars with 21g and 28g of LiNO3 became smaller. In the case of A4-ID and

A6-NM the 14-day, 21-day, and 28-day expansions of bars with 28g of LiNO3 were

almost the same as the expansions of bars with 21g of LiNO3 (Figures 10.44 through

Figure 11.56: Comparison of the 14-Day C 1260 Expansions for the Different LiNO3 Dosages

291

10.48). This might be explained by the leaching theory that can be stated as follows:

As time progresses, LiNO3 starts leaching out of the mortar bars and into the

solution. Less LiNO3 is present in the bars for suppressing the ASR reaction, which

results in increased expansions. That is why the expansion of mortar bars with 28g

LiNO3 increase and become closer to the expansions of bars with 21g LiNO3.

Table 11.16: Effect of LiNO3 on the 14-Day C 1260 Expansions

Aggregate ID

C 1260 14-Day

Expansion

C 1260 Classification

LiNO3 Weight

21 g 28 g 60 g

A6-NM 0.91% H.R. H.R. H.R. H.R. A4-ID 0.79% H.R. H.R. H.R. S.R.

A2-WY 0.29% H.R. Innocuous Innocuous Innocuous C2-SD 0.17% S.R. S.R. Innocuous Innocuous B4-VA 0.15% S.R. Innocuous Innocuous Innocuous E2-IA 0.42% H.R. Innocuous Innocuous Innocuous

H.R. = Highly Reactive = C 1260 14-day expansion > 0.20% S.R. = Slowly Reactive = 0.10% < C 1260 14-day expansion < 0.20%

Innocuous = C 1260 14-day expansion < 0.10%

292

11.10 SUMMARY OF MITIGATION ALTERNATIVE INVESTIGATION USING C 1260

ASTM C 1260 was used to evaluate the effectiveness of the mitigation

alternatives using a 14-day expansion of 0.10% as a criterion. Table 11.17 includes a

summary of this evaluation. As can be seen from this table, the only alternatives that

were effective with all six aggregates are the use of 70% granulated slag and 25%

calcined clay. Twenty-five percent Class F fly ash and 55% slag were effective with

four out of the six aggregate with the exception being the very reactive aggregate

A6-NM (14-day expansion of 0.91%). Alternatives that were effective with slowly

reactive aggregates (B4-VA and C2-SD) are the use of 35% Class C fly ash, 15%

and 25% Class F fly ash, 10% silica fume, 40% and 70% slag, 17% and 25%

calcined clay, and 60g of LiNO3. Alternatives that were effective with the highly

reactive aggregate A2-WY are the use of 25% Class F fly ash, 55% and 70% slag,

25% calcined clay, and 60g of LiNO3. Alternatives that were effective with the

highly reactive aggregate A6-NM are the use of 70% slag and 25% calcined clay. It

seems that different levels of aggregate reactivity require different mitigation

alternatives. It should be noted that aggregate E2-IA, which was classified as highly

reactive when tested in accordance to C 1260 but innocuous when tested according to

C 1293, exhibited identical reaction to the mitigation alternatives as the reaction of

A2-WY. The 14-day expansions of E2-IA and A2-WY were 0.42% and 0.29%

respectively, which puts them in the same reactivity category.

293

Table 11.17: Effectiveness of the Mitigation Alternatives Using the 14-day of 0.10% Criteria

Cementitious Material

Replacement Level by

Weight of Cement

Aggregate, 14-day expansion, (C 1260 Classification) A6-NM 0.91% (H.R.)

A4-ID 0.79% (H.R.)

A2-WY 0.29% (H.R.)

C2-SD 0.17% (S.R.)

B4-VA 0.15% (S.R.)

E2-IA 0.42% (H.R.)

Class C Fly Ash

20% H.R. H.R. H.R. S.R. S.R. H.R. 27.5% H.R. H.R. H.R. S.R. Innocuous H.R. 35% H.R. S.R. S.R. Innocuous Innocuous S.R.

Class F Fly Ash

15% H.R. H.R. S.R. S.R. Innocuous S.R. 25% S.R. S.R. Innocuous Innocuous Innocuous Innocuous

Silica Fume

5% H.R. H.R. H.R. S.R. S.R. H.R. 10% S.R. S.R. S.R. Innocuous Innocuous S.R.

Granulated Slag

40% H.R. H.R. S.R. S.R. Innocuous S.R. 55% S.R. Innocuous Innocuous Innocuous Innocuous Innocuous 70% Innocuous Innocuous Innocuous Innocuous Innocuous Innocuous

Calcined Clay

17% S.R. S.R. S.R. Innocuous Innocuous S.R. 25% Innocuous Innocuous Innocuous Innocuous Innocuous Innocuous

Chemical Material Dosage

Aggregate, 14-day expansion, (C 1260 Classification) A6-NM 0.91% (H.R.)

A4-ID 0.79% (H.R.)

A2-WY 0.29% (H.R.)

C2-SD 0.17% (S.R.)

B4-VA 0.15% (S.R.)

E2-IA 0.42% (H.R.)

Lithium Nitrate

21 g H.R. H.R. Innocuous S.R. Innocuous Innocuous 28 g H.R. H.R. Innocuous Innocuous Innocuous Innocuous 60 g H.R. S.R. Innocuous Innocuous Innocuous Innocuous

Entrained Air

4% H.R. H.R. S.R. S.R. Innocuous S.R. 8% H.R. H.R. S.R. S.R. Innocuous S.R. H.R. = Highly Reactive = C 1260 14-day expansion > 0.20% S.R. = Slowly Reactive = 0.10% < C 1260 14-day expansion < 0.20%

Innocuous = C 1260 14-day expansion < 0.10%

294

11.11 EFFECTIVENESS OF THE MITIGATION ALTERNATIVES AT DIFFERENT CEMENT ALKALI CONTENT

It has been suggested by Stark (1993) and investigated by this research, that

changing the normality of the NaOH solution in the C 1260 test can be used to

determine the reactivity of aggregates at a certain cement alkali level corresponding

to the solution normality (Section 4.18.2, eq. 4.4, Section 9.7). As the normality of

the solution decreases, the equivalent alkali content of the mortar bars decreases, and

the need for mitigation decreases. This concept was investigated using mitigation

alternatives for the following purposes:

1. Determine the effect of decreasing the NaOH solution normality on the

effectiveness of mitigation alternatives.

2. Mitigate the excessive expansions of highly reactive aggregates by using low

alkali content and a mitigation alternative.

The mitigation methods used for these procedures were Class C fly ash, Class F

fly ash, granulated slag, silica fume, calcined clay, and air entrainment in

combination with the highly reactive aggregate A6-NM. The use of LiNO3 was not

evaluated because it proved to be effective with highly reactive aggregates at

reasonable levels. The investigated NaOH solution normalities were the standard

1.0N corresponding to 1.50% Na2Oequiv., 0.75N corresponding to 1.15% Na2Oequiv.,

0.5N corresponding to 0.80% Na2Oequiv., and 0.35N Corresponding to 0.6%

Na2Oequiv..

Results of these procedures are presented in Table 11.18 and Figures 11.57

through 11.68.

295

Table 11.18: Expansion Results of A6-NM Used with Mitigation Alternatives at Different Cement Alkali Content

Mixture ID Expansion, %

4-Day 7-Day 11-Day 14-Day 21-Day 28-Day Class C Fly Ash

A6-NM-0.75N-FAC 25% 0.08 0.15 0.23 0.26 0.34 0.41 A6-NM-0.75N-FAC 35% 0.02 0.06 0.08 0.11 0.17 0.22 A6-NM-0.5N-FAC 25% 0.01 0.03 0.05 0.07 0.10 0.12 A6-NM-0.5N-FAC 35% 0.00 0.01 0.01 0.02 0.03 0.05 A6-NM-0.35N-FAC 25% 0.00 0.02 0.04 0.05 0.09 0.10 A6-NM-0.35N-FAC 35% 0.00 0.00 0.01 0.01 0.02 0.02 Class F Fly Ash A6-NM-0.75N-FAF 15% 0.06 0.11 0.19 0.23 0.31 0.38 A6-NM-0.75N-FAF 20% 0.02 0.04 0.09 0.12 0.19 0.25 A6-NM-0.5N-FAF 15% 0.01 0.03 0.07 0.09 0.13 0.15 A6-NM-0.5N-FAF 20% 0.00 0.01 0.02 0.02 0.05 0.06 A6-NM-0.35N-FAF 15% 0.00 0.03 0.07 0.09 0.13 0.15 A6-NM-0.35N-FAF 20% 0.00 0.00 0.01 0.01 0.03 0.03 Granulated Slag A6-NM-0.75N-SL 25% 0.24 0.38 0.54 0.61 0.74 0.85 A6-NM-0.75N-SL 50% 0.02 0.03 0.09 0.12 0.18 0.25 A6-NM-0.5N-SL 25% 0.02 0.10 0.18 0.23 0.32 0.37 A6-NM-0.5N-SL 50% 0.00 0.00 0.01 0.01 0.02 0.03 A6-NM-0.35N-SL 25% 0.01 0.08 0.16 0.21 0.33 0.38 A6-NM-0.35N-SL 50% 0.00 0.00 0.00 0.00 0.01 0.02 Silica Fume A6-NM-0.75N-SF 5% 0.20 0.39 0.62 0.75 0.99 1.13 A6-NM-0.75N-SF 10% 0.03 0.09 0.20 0.26 0.42 0.57 A6-NM-0.5N-SF 5% 0.02 0.10 0.21 0.27 0.40 0.47 A6-NM-0.5N-SF 10% 0.00 0.01 0.01 0.02 0.05 0.08 A6-NM-0.35N-SF 5% 0.01 0.08 0.18 0.24 0.39 0.47 A6-NM-0.35N-SF 10% 0.00 0.00 0.01 0.01 0.03 0.04 Air Entrainment A6-NM-0.75N-AE 4% 0.17 0.27 0.38 0.42 0.48 0.52 A6-NM-0.5N-AE 4% 0.05 0.11 0.17 0.21 0.27 0.29 A6-NM-0.35N-AE 4% 0.03 0.07 0.12 0.14 0.20 0.22

296

Table 11.18: Expansion Results of A6-NM Used with Mitigation Alternatives at Different Cement Alkali Content (Cont’d)

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

Mixture ID Calcined Clay A6-NM-0.75N-CC 17% 0.01 0.03 0.07 0.12 0.15 0.20 A6-NM-0.5N-CC 17% 0.00 0.00 0.01 0.03 0.05 0.08

A6-NM-0.35N-CC 17% 0.00 0.00 0.01 0.01 0.02 0.02

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

A6-NM-1N-FAC 0%

A6-NM-1N- FAC 35%

A6-NM-0.75N-FAC 25%

A6-NM-0.75N-FAC 35%

A6-NM-0.5N-FAC 25%

A6-NM-0.5N-FAC 35%

A6-NM-0.35N-FAC 25%

A6-NM-0.35N-FAC 35%

Figure 11.57: Effect of Class C Fly Ash at Different Cement Alkali Contents for the Highly Reactive A6-NM

297

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

A6-NM-1N-FAF 0%

A6-NM-1N- FAF 25%

A6-NM-0.75N-FAF 15%

A6-NM-0.75N-FAF 20%

A6-NM-0.5N-FAF 15%

A6-NM-0.5N-FAF 20%

A6-NM-0.35N-FAF 15%

A6-NM-0.35N-FAF 20%

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32Time, Days

Exp

ansi

on, %

A6-NM-1N-SL 0%

A6-NM-1N- SL 55%

A6-NM-0.75N-SL 25%

A6-NM-0.75N-SL 50%

A6-NM-0.5N-SL 25%

A6-NM-0.5N-SL 50%

A6-NM-0.35N-SL 25%

A6-NM-0.35N-SL 50%

Figure 11.58: Effect of Class F Fly Ash at Different Cement Alkali Contents for the Highly Reactive A6-NM

Figure 11.59: Effect of Granulated Slag at Different Cement Alkali Contents for the Highly Reactive A6-NM

298

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32Time, Days

Exp

ansi

on, %

A6-NM-1N-SF 0%

A6-NM-1N- SF 10%

A6-NM-0.75N-SF 5%

A6-NM-0.75N-SF 10%

A6-NM-0.5N-SF 5%

A6-NM-0.5N-SF 10%

A6-NM-0.35N-SF 5%

A6-NM-0.35N-SF 10%

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

A6-NM-1N-AE 0%

A6-NM-1N- AE 8%

A6-NM-0.75N-AE 4%

A6-NM-0.5N-AE 4%

A6-NM-0.35N-AE 4%

Figure 11.60: Effect of Silica Fume at Different Cement Alkali Contents for the Highly Reactive A6-NM

Figure 11.61: Effect of Air Entrainment at Different Cement Alkali Contents for the Highly Reactive A6-NM

299

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32Time, Days

Exp

ansi

on, %

A6-NM-1N-CC 0%

A6-NM-1N- CC 17%

A6-NM-0.75N-CC 17%

A6-NM-0.5N-CC 17%

A6-NM-0.35N-CC 17%

Figure 11.62: Effect of Calcined at Different Cement Alkali Contents for

the Highly Reactive A6-NM

300

0.000.020.040.060.080.100.120.140.160.180.200.220.240.260.280.30

A6-NMInvestigated Aggregate

14-D

ay E

xpan

sion

, % A6-NM-1N-FAC 0%A6-NM-1N- FAC 35%A6-NM-0.75N-FAC 35%A6-NM-0.5N-FAC 35%A6-NM-0.35N-FAC 35%

Failure Criterion0.35N and 0.50N

Failure Criterion0.75N

0.000.020.040.060.080.100.120.140.160.180.200.220.240.260.280.30

A6-NMInvestigated Aggregate

14-D

ay E

xpan

sion

, % A6-NM-1N-FAC 0%A6-NM-0.75N-FAC 25%A6-NM-0.5N-FAC 25%A6-NM-0.35N-FAC 25%

Failure Criterion0.35N and 0.50N

Failure Criterion0.75N

Figure 11.63a: Comparison of the 14-Day Expansions for the Combination of 35% Class C Fly Ash with Different Cement Alkali Contents

Figure 11.63b: Comparison of the 14-Day Expansions for the Combination of 25% Class C Fly Ash with Different Cement Alkali Contents

301

0.000.020.040.060.080.100.120.140.160.180.200.220.240.260.280.30

A6-NMInvestigated Aggregate

14-D

ay E

xpan

sion

, % A6-NM-1N-FAF 0%A6-NM-1N- FAF 25%A6-NM-0.75N-FAF 20%A6-NM-0.5N-FAF 20%A6-NM-0.35N-FAF 20%

Failure Criterion0.35N and 0.50N

Failure Criterion0.75N

0.000.020.040.060.080.100.120.140.160.180.200.220.240.260.280.30

A6-NMInvestigated Aggregate

14-D

ay E

xpan

sion

, % A6-NM-1N-FAF 0%A6-NM-0.75N-FAF 15%A6-NM-0.5N-FAF 15%A6-NM-0.35N-FAF 15%

Failure Criterion0.35N and 0.50N

Failure Criterion0.75N

Figure 11.64a: Comparison of the 14-Day Expansions for the Combination of 20% Class F Fly Ash with Different Cement Alkali Contents

Figure 11.64b: Comparison of the 14-Day Expansions for the Combination of 15% Class F Fly Ash with Different Cement Alkali Contents

302

0.000.020.040.060.080.100.120.140.160.180.200.220.240.260.280.30

A6-NMInvestigated Aggregate

14-D

ay E

xpan

sion

, % A6-NM-1N-SL 0%A6-NM-1N- SL 55%A6-NM-0.75N-SL 50%A6-NM-0.5N-SL 50%A6-NM-0.35N-SL 50%

Failure Criterion0.35N and 0.50N

Failure Criterion0.75N

0.000.020.040.060.080.100.120.140.160.180.200.220.240.260.280.30

A6-NMInvestigated Aggregate

14-D

ay E

xpan

sion

, %

A6-NM-1N-SL 0%A6-NM-0.75N-SL 25%A6-NM-0.5N-SL 25%A6-NM-0.35N-SL 25%

Failure Criterion0.35N and 0.50N

Failure Criterion0.75N

Figure 11.65a: Comparison of the 14-Day Expansions for the Combination of 50% Granulated Slag with Different Cement Alkali Contents

Figure 11.65b: Comparison of the 14-Day Expansions for the Combination of 25% Granulated Slag with Different Cement Alkali Contents

303

0.000.020.040.060.080.100.120.140.160.180.200.220.240.260.280.30

A6-NMInvestigated Aggregate

14-D

ay E

xpan

sion

, % A6-NM-1N-SF 0%A6-NM-1N- SF 10%A6-NM-0.75N-SF 10%A6-NM-0.5N-SF 10%A6-NM-0.35N-SF 10%

Failure Criterion0.35N and 0.50N

Failure Criterion0.75N

0.000.020.040.060.080.100.120.140.160.180.200.220.240.260.280.30

A6-NMInvestigated Aggregate

14-D

ay E

xpan

sion

, %

A6-NM-1N-SF 0%A6-NM-0.75N-SF 5%A6-NM-0.5N-SF 5%A6-NM-0.35N-SF 5%

Failure Criterion0.35N and 0.50N

Failure Criterion0.75N

Figure 11.66a: Comparison of the 14-Day Expansions for the Combination of 10% Silica Fume with Different Cement Alkali Contents

Figure 11.66b: Comparison of the 14-Day Expansions for the Combination of 5% Silica Fume with Different Cement Alkali Contents

304

0.000.020.040.060.080.100.120.140.160.180.200.220.240.260.280.30

A6-NMInvestigated Aggregate

14-D

ay E

xpan

sion

, % A6-NM-1N-AE 0%A6-NM-1N- AE 8%A6-NM-0.75N-AE 4%A6-NM-0.5N-AE 4%A6-NM-0.35N-AE 4%

Failure Criterion0.35N and 0.50N

Failure Criterion0.75N

0.000.020.040.060.080.100.120.140.160.180.200.220.240.260.280.30

A6-NMInvestigated Aggregate

14-D

ay E

xpan

sion

, % A6-NM-1N-CC 0%A6-NM-1N- CC 17%A6-NM-0.75N-CC 17%A6-NM-0.5N-CC 17%A6-NM-0.35N-CC 17%

Failure Criterion0.35N and 0.50N

Failure Criterion0.75N

Figure 11.67: Comparison of the 14-Day Expansions for the Combination of Air Entrainment with Different Cement Alkali Contents

Figure 11.68: Comparison of the 14-Day Expansions for the Combination of Calcined Clay with Different Cement Alkali Contents

305

It was also suggested by Stark (1993) that lowering the normality of the solution

in which the mortar bars are stored for 14 days, has to be accompanied with a lower

14-day expansion limit as mentioned in Table 11.19.

Table 11.19: Exposure Solution Normalities Investigated and Their Corresponding Na2Oequiv. content and Recommended Expansion Limits

Investigated Normality

1N (Standard)

0.75N 0.50N 0.35N

Corresponding Na2Oeqiv. Content

1.5% 1.15% 0.81% 0.6%

14-Day Expansion

Limit

0.10% 0.04% 0.04% 0.02%

11.11.1 Effect of Class C Fly Ash Coupled with Various Cement Alkali

Contents

Using Class C fly ash to replace 35% of the weight of cement was not effective in

reducing the mortar bar expansions of A6-NM (a highly reactive aggregate) below

the 14-day limit of 0.10% when the bars were tested using the standard 1N NaOH

solution (1.5% Na2Oequiv.). As the normality of the testing solution decreased, the

effectiveness of the Class C fly ash increased for both fly ash contents (Figures 11.57

and 11.63). At 0.75N (1.15% Na2Oequiv.), using 35% Class C fly ash was also not

effective in lowering the 14-day expansions below the limit. An alkali content

between 0.60% and 0.81% (0.35N and 0.50N) and the use of 35% Class C fly ash

were required to limit the 14-day expansions of A6-NM below 0.02%. Using 25%

Class C fly ash was not effective at any investigated alkali content. These

observations are summarized in Table 11.20. Thus, in order for Class C fly ash to be

able to mitigate the deleterious ASR expansions of the investigated highly reactive

aggregate, it should be used to replace 35% of the weight of a cement with an alkali

content of 0.80% or lower.

306

Table 11.20: Effectiveness of Class C Fly Ash at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day)

Investigated Normality 1N (Standard) 0.75N 0.50N 0.35N

Corresponding Na2Oeqiv. Content 1.5% 1.15% 0.81% 0.6% Mitigation Alternative

Replacement Level Evaluation

Class C Fly Ash

25% Reactive Reactive Reactive Reactive 35% Reactive Reactive Innocuous Innocuous

Reactive = Alternative exhibiting 14-day expansion higher than Table 11.19 limits Innocuous = Alternative exhibiting 14-day expansions lower than Table 11.19 limits

11.11.2 Effect of Class F Fly Ash Coupled with Various Cement Alkali Contents

When tested using the standard 1N NaOH solution, Class F fly ash was not

effective in decreasing the deleterious expansions of the highly reactive aggregate

A6-NM below safe levels even when it was used to replace 25% of the weight of

cement. As the normality of the testing solution was decreased, the corresponding

alkali content of the cement decreased, and the effectiveness of the Class F fly ash

increased for both fly ash contents investigated (Figures 11.58 and 11.64). Using

20% Class F fly ash at 0.75N was not effective in decreasing the 14-day expansions

below the proposed safe levels. It was as effective as using 25% Class F fly ash at

1N. It was noticed that when using the 0.5N and 0.35N solution normalities to

respectively represent the cases of 0.81 and 0.61% alkali content, 20% Class F fly

ash was required to decrease the 14-day expansions below 0.02%. Fifteen-percent

Class F fly ash was not effective even when tested in a 0.35N solution. Thus, in order

to mitigate the deleterious expansions of the highly reactive aggregate A6-NM, a

cement with an alkali content lower than 0.80% in combination with 20% Class F fly

ash was required. A summary of these observations is presented in Table 11.21.

307

Table 11.21: Effectiveness of Class F Fly Ash at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day)

Investigated Normality 1N (Standard) 0.75N 0.50N 0.35N

Corresponding Na2Oeqiv. Content 1.5% 1.15% 0.81% 0.6% Mitigation Alternative

Replacement Level Evaluation

Class F Fly Ash

15% Reactive Reactive Reactive Reactive 20% Reactive Reactive Innocuous Innocuous

Reactive = Alternative exhibiting 14-day expansion higher than Table 11.19 limits Innocuous = Alternative exhibiting 14-day expansions lower than Table 11.19 limits 11.11.3 Effect of Granulated Slag Coupled with Various Cement Alkali Content

Using granulated slag to replace 70% of the cement weight was effective in

mitigating the deleterious expansions of the highly reactive aggregate A6-NM when

the combination was evaluated using the 1N NaOH solution (1.5% Na2Oequiv.). In

order to determine whether lower percentages of granulated slag can be used with

lower cement alkali contents, the solution normality was decreased. It was noticed in

Figures 11.59 and 11.65 that using 25% slag was not effective in mitigating the

deleterious alkali-silica reaction even when a solution normality of 0.35N was used

(0.6% Na2Oequiv.). When the A6-NM and slag combination was investigated using the

0.75N (1.15% Na2Oequiv.) solution normality, 50% slag was found to be not effective

in lowering the 14-day expansions below safe limits. However, 50% slag was

effective when evaluated using the 0.50N (0.80% Na2Oequiv.) and 0.35N (0.60%

Na2Oequiv.) in decreasing the 14-day expansions below 0.02%. Thus, 70% slag can be

used in combination with any alkali cement content (as high as 1.5% Na2Oequiv.). If a

lower alkali content cement is used then the required slag percentage might be

decreased to 50% giving that the cement alkali content is lower than 0.8% Na2Oequiv..

Table 11.22 includes a summary of these observations.

308

Table 11.22: Effectiveness of Granulated Slag at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day)

Investigated Normality 1N (Standard) 0.75N 0.50N 0.35N

Corresponding Na2Oeqiv. Content 1.5% 1.15% 0.81% 0.6% Mitigation Alternative

Replacement Level Evaluation

Granulated Slag

25% Reactive Reactive Reactive Reactive 50% Reactive Reactive Innocuous Innocuous

Reactive = Alternative exhibiting 14-day expansion higher than Table 11.19 limits Innocuous = Alternative exhibiting 14-day expansions lower than Table 11.19 limits

11.11.4 Effect of Silica Fume Coupled with Various Cement Alkali Content

When evaluated using the 1N NaOH solution, the use of 10% silica fume was not

effective in decreasing the 14-day expansions of A6-NM below safe levels. This

level of replacement was effective when the solution normality was dropped to

0.50N and 0.35N at which levels the 14-day expansions of A6-NM were reduced to

lower than 0.02% (Figures 11.60 and 11.66). Using 5% silica fume was not effective

even when evaluated using the 0.35N NaOH solution. Thus, in order to mitigate the

ASR reaction of A6-NM, the use of 10% silica fume had to be coupled with the use

of a cement with an alkali content lower than 0.8%. Table 11.23 illustrates these

observations.

Table 11.23: Effectiveness of Silica Fume at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day)

Investigated Normality 1N (Standard) 0.75N 0.50N 0.35N

Corresponding Na2Oeqiv. Content 1.5% 1.15% 0.81% 0.6% Mitigation Alternative

Replacement Level Evaluation

Silica Fume 5% Reactive Reactive Reactive Reactive 10% Reactive Reactive Innocuous Innocuous

Reactive = Alternative exhibiting 14-day expansion higher than Table 11.19 limits Innocuous = Alternative exhibiting 14-day expansions lower than Table 11.19 limits

309

11.11.5 Effect of Air Entrainment Coupled with Various Cement Alkali Content

Using air entrainment to lower the 14-day expansions of A6-NM below safe

levels was not effective even when the mortar bars were investigated using the 0.35N

solution (Figures 10.61 and 10.67). Thus, even though air entrainment contributes in

decreasing the expansions of A6-NM, it cannot be used to mitigate the reaction even

when it was coupled with low alkali cement as seen in Table 11.24.

Table 11.24: Effectiveness of Air Entrainment at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day)

Investigated Normality 1N (Standard) 0.75N 0.50N 0.35N

Corresponding Na2Oeqiv. Content 1.5% 1.15% 0.81% 0.6% Mitigation Alternative

Replacement Level Evaluation

Air Entrainment 5% Reactive Reactive Reactive Reactive10% Reactive Reactive Reactive Reactive

Reactive = Alternative exhibiting 14-day expansion higher than Table 11.19 limits Innocuous = Alternative exhibiting 14-day expansions lower than Table 11.19 limits

11.11.6 Effect of Calcined Clay Coupled with Various Cement Alkali Content When evaluated using the 1N NaOH solution, the use of 17% calcined clay was

not effective in decreasing the 14-day expansions of A6-NM below safe levels.

Twenty five percent calcined clay was required. The 17% level of replacement was

effective when the solution normality was dropped to 0.50N and 0.35N at which

levels the 14-day expansions of A6-NM were reduced to lower than 0.02% (Figures

11.62 and 11.68). Thus, in order to mitigate the ASR reaction of A6-NM, the use of

17% calcined clay had to be coupled with the use of a cement with an alkali content

lower than 0.8%. Table 11.24 illustrates these observations.

310

Table 11.25: Effectiveness of Calcined Clay at Different Cement Alkali Contents with the Highly Reactive Aggregate A6-NM (0.92% C1260, 14-Day)

Investigated Normality 1N (Standard) 0.75N 0.50N 0.35N

Corresponding Na2Oeqiv. Content 1.5% 1.15% 0.81% 0.6%

Mitigation Alternative

Replacement Level Evaluation

Air Entrainment

25% Innocuous Innocuous Innocuous Innocuous17% Reactive Reactive Innocuous Innocuous

Reactive = Alternative exhibiting 14-day expansion higher than Table 11.19 limits Innocuous = Alternative exhibiting 14-day expansions lower than Table 11.19 limits

11.12 EVALUATION OF THE MITIGATION ALTERNATIVES C 1260 RESULTS USING KOLMOGOROV-AVRAMI-MEHL-JOHNSTON’S MODEL

The Kolmogorov-Avrami-Mehl-Johnson’s (K-A-M-J) model, described earlier in

section 4.18.5, was used to evaluate the results of the test of different alternatives for

mitigating the excessive expansions caused by ASR. The 3-, 7-, 11-, and 14-day C

1260 results were used to determine the variables required by the model and they are

ln (K) and M. Results are presented in Figures 11.69 through 11.80. A second set of

variables was developed using the 3-, 7-, 11-, 14-, 21-, and 28-day C 1260 results.

Results for the 28-day set are presented in Appendix B.

311

-10.0-9.0-8.0-7.0-6.0-5.0-4.0-3.0-2.0-1.00.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Ln

(K)

20% Class C27.5% Class C35% Class C15% Class F25% Class F

Figure 11.69: Ln (K) values for Various Class C and Class F fly ash Replacement Levels Using 14-Day C 1260 Results

Failure Limit

312

-12.0

-10.0

-8.0

-6.0

-4.0

-2.0

0.0A6-NM A4-ID A2-WY C2-SD B4-VA

Ln

(K)

5% Silica Fume10% Silica Fume40% Slag55% Slag70% Slag

-10.0-9.0-8.0-7.0-6.0-5.0-4.0-3.0-2.0-1.00.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Ln

(K)

17% Calcined Clay

25% Calcined Clay

21g Lithium Nitrate

28g lithium Nitrate

60g Lithium Nitrate

Figure 11.70: Ln (K) values for Various Silica Fume and Granulated Slag Replacement Levels Using 14-Day C 1260 Results

Figure 11.71: Ln (K) values for Various Calcined Clay and LiNO3 Replacement Levels Using 14-Day C 1260 Results

Failure Limit

Failure Limit

313

-10.0-9.0-8.0-7.0-6.0-5.0-4.0-3.0-2.0-1.00.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Ln

(K)

4% Entrained Air8% Entrained AirW/C = 0.35W/C = 0.55W/C = 0.65

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

A6-NM A4-ID A2-WY C2-SD B4-VA

Con

stan

t M

20% Class C27.5% Class C35% Class C15% Class F25% Class F

Figure 11.72: Ln (K) values for Various Air Entrainment Levels and Various Water-Cement Ratios Using 14-Day C 1260 Results

Figure 11.73: M values for Various Class C and Class F Fly Ash Replacement Levels Using 14-Day C 1260 Results

Failure Limit

Failure Limit

314

0.0

0.5

1.0

1.5

2.0

2.5

3.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Con

stan

t M

5% Silica Fume10% Silica Fume40% Slag55% Slag70% Slag

0.0

0.5

1.0

1.5

2.0

2.5

3.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Con

stan

t M

17% Calcined Clay

25% Calcined Clay

21g Lithium Nitrate

28g lithium Nitrate

60g Lithium Nitrate

Figure 11.74: M values for Various Silica Fume and Granulated Slag Replacement Levels Using 14-Day C 1260 Results

Figure 11.75: M values for Various Calcined Clay and LiNO3 Replacement Levels Using 14-Day C 1260 Results

Failure Limit

Failure Limit

315

0.0

0.5

1.0

1.5

2.0

2.5

3.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Con

stan

t M

4% Entrained Air8% Entrained AirW/C = 0.35W/C = 0.55W/C = 0.65

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

-10.0 -8.0 -6.0 -4.0 -2.0 0.0Ln (K)

Con

stan

t M 20% Class C27.5% Class C35% Class C15% Class F25% Class F

Figure 11.76: M values for Various Air Entrainment Levels and Various Water-Cement Ratios Using 14-Day C 1260 Results

Figure 11.77: Ln (K) vs. M Plot for the Class C and Class F Fly Ash C 1260 Results

Failure Limit

Failure Limit

316

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

-10.0 -8.0 -6.0 -4.0 -2.0 0.0Ln (K)

Con

stan

t M

5% Silica Fume10% Silica Fume40% Slag55% Slag70% Slag

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

-10.0 -8.0 -6.0 -4.0 -2.0 0.0Ln (K)

Con

stan

t M

17% Calcined Clay25% Calcined Clay21g Lithium Nitrate28g lithium Nitrate60g Lithium Nitrate

Figure 11.78: Ln (K) vs. M Plot for the Silica Fume and Granulated Slag C 1260 Results

Figure 11.79: Ln (K) vs. M Plot for the Calcined Clay and LiNO3 C 1260 Results

Failure Limit

Failure Limit

317

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

-10.0 -8.0 -6.0 -4.0 -2.0 0.0Ln (K)

Con

stan

t M

4% Entrained Air8% Entrained AirW/C = 0.35W/C = 0.55W/C = 0.65

For a mitigation alternative to be effective, it should have ln (k) values that are

more negative than –6. Using this criterion, the effectiveness of the investigated

mitigation alternatives is evaluated in Table 11.26.

It can be inferred from Table 11.26 that the only alternatives that were

effective with all six aggregates are the use of 70% granulated slag and 25% calcined

clay. Alternatives that were effective with slowly reactive aggregates (B4-VA and

C2-SD) are the use of 25% Class F fly ash, 70% slag, 17 and 25% calcined clay, and

60g of LiNO3. Alternatives that were effective with the moderately reactive

aggregate A2-WY are the use of 70% slag and 25% calcined clay. Alternatives that

were effective with the highly reactive aggregates A4-ID and A6-NM are the use of

70% slag and 25% calcined clay. It seems that different levels of aggregate reactivity

require different mitigation alternatives.

The use of both criteria, 14-day expansion of 0.10% and Ln (k) = -6, resulted in

the conclusion that the only mitigation alternatives that are effective with all

Figure 11.80: Ln (K) vs. M Plot for the Air Entrainment and Various W/C C 1260 Results

Failure Limit

318

aggregates are the use of 70% slag and 25% calcined clay. The evaluation differed

slightly when it came to the individual aggregates.

Table 11.26: Mitigation Alternatives Results Using K-A-M-J’s Ln (k) = -6 Note: Not Effective = ln(k) > -6 and Effective = ln(k) < -6

Mitigation Alternative

ReplacementLevel A6-NM A4-ID A2-WY B4-VA C2-SD

Class C Fly Ash

20% Not Effective

Not Effective

Not Effective

Not Effective

Not Effective

27.5% Not Effective

Not Effective

Not Effective

Not Effective

Not Effective

35% Not Effective

Not Effective

Not Effective

Not Effective

Not Effective

Class F Fly Ash

15% Not Effective

Not Effective

Not Effective

Not Effective Effective

25% Not Effective

Not Effective

Not Effective Effective Effective

Silica Fume 5% Not

Effective Not

Effective Not

Effective Not

Effective Not

Effective

10% Not Effective Effective Not

Effective Not

Effective Effective

Granulated Slag

40% Not Effective

Not Effective

Not Effective

Not Effective Effective

55% Not Effective Effective Not

Effective Not

Effective Effective

70% Effective Effective Effective Effective Effective

Calcined Clay 17% Not Effective

Not Effective

Not Effective Effective Effective

25% Effective Effective Effective Effective Effective

Lithium Nitrate

21 g Not Effective

Not Effective

Not Effective

Not Effective Effective

28 g Not Effective

Not Effective

Not Effective

Not Effective Effective

60 g Not Effective Effective Not

Effective Effective Effective

Entrained Air 4% Not

Effective Not

Effective Not

Effective Not

Effective Not

Effective

8% Not Effective

Not Effective

Not Effective

Not Effective

Not Effective

319

11.13 PREDICTIONS OF EFFECTIVE LEVELS OF REPLACEMENT USING K-M-A-J’S MODEL

Since the investigated levels of cement replacement with Class C fly ash, Class F

fly ash and silica fume were found not effective in mitigating ASR when evaluated

using the K-M-A-J’s model, the model was used to predict effective levels of

replacement. Results are presented in Table 11.27 and Appendix C. The

effectiveness of some of the predictions is demonstrated in Figure 11.81 through

11.86. Results of the C 1260 investigation of some of the predicted levels are

presented in Table 11.28.

Table 11.27: Predicted Levels of Replacement Using the K-M-A-J’s Model A6-NM

H.R. A4-ID H.R.

A2-WY M.R.

C2-SD S.R.

B4-VA S.R.

Class C Fly Ash 50% 65% 80% 45% 50%

Class F Fly Ash 40% 30% 30% 15% 20%

Silica Fume 20% 15% 15% 8% 20%

H.R. = Highly Reactive M.R. = Moderately Reactive S.R. = Slowly Reactive Highlighted Box = Values that were Investigated Not Highlighted Box = Values that were effective before

320

Table 11.28: C 1260 Expansions of Some Predicted Values of the K-M-A-J’s Model

Aggregate ID

Mitigation Alternative

ReplacementLevel

Expansion, % 4-Day 7-Day 11-Day 14-Day 21-Day 28-Day

A2-WY

A2-WY Class C Fly Ash 80% 0.01 0.01 0.01 0.01 0.01 0.01

A2-WY Class F Fly Ash 30% 0.00 0.00 0.00 0.02 0.03 0.04

A2-WY Silica Fume 15% 0.01 0.03 0.04 0.07 0.11 0.14

A4-ID

A4-ID Class C Fly Ash 65% 0.00 0.01 0.01 0.02 0.02 0.03

A4-ID Class F Fly Ash 30% 0.00 0.01 0.02 0.03 0.06 0.11

A4-ID Silica Fume 10% 0.02 0.03 0.05 0.08 0.14 0.19

A6-NM

A6-NM Class C Fly Ash 50% 0.00 0.01 0.01 0.02 0.03 0.03

A6-NM Class F Fly Ash 40% 0.00 0.01 0.01 0.02 0.04 0.06

A6-NM Silica Fume 20% 0.02 0.03 0.05 0.09 0.16 0.22

B4-VA

B4-VA Class C Fly Ash 50% 0.01 0.02 0.04 0.04 0.06 0.10

B4-VA Silica Fume 20% 0.02 0.03 0.05 0.05 0.08 0.12

C2-SD

C2-SD Class C Fly Ash 45% 0.00 0.01 0.01 0.02 0.03 0.04

321

-0.050.000.050.100.150.200.250.300.350.40

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

A2-WY 0%A2-WY-FAC 80%A2-WY-FAF 30%A2-WY-SF 15%

0.000.100.200.300.400.500.600.700.800.901.001.10

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

A4-ID 0%A4-ID-FAC 65%A4-ID-FAF 30%A4-ID-SF 10%

Figure 11.81: Effectiveness of the K-M-A-J Model Predictions for Aggregate A2-WY

Figure 11.82: Effectiveness of the K-M-A-J Model Predictions for Aggregate A4-ID

322

0.000.100.200.300.400.500.600.700.800.901.001.101.20

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

A6-NM 0%A6-NM-FAC 50%A6-NM-FAF 40%A6-NM-SF 20%

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, %

B4-VA 0%B4-VA-FAC 50%B4-VA-SF 20%

Figure 11.83: Effectiveness of the K-M-A-J Model Predictions for Aggregate A6-NM

Figure 11.84: Effectiveness of the K-M-A-J Model Predictions for Aggregate B4-VA

323

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 4 8 12 16 20 24 28 32

Time, Days

Exp

ansi

on, % C2-SD 0%

C2-SD-FAC 45%

0.000.100.20

0.300.400.500.600.70

0.800.901.00

A6-NM A4-ID A2-WY C2-SD B4-VA

Investigated Aggregate

14-D

ay E

xpan

sion

, %

40%

Cla

ss F

Fly

Ash

30%

Cla

ss F

Fly

Ash

30%

Cla

ss F

Fly

Ash

20%

Sili

ca F

ume

65%

Cla

ss C

Fly

Ash

15%

Sili

ca F

ume

80%

Cla

ss C

Fly

Ash

20%

Sili

ca F

ume

45%

Cla

ss C

Fly

Ash

50%

Cla

ss C

Fly

Ash

15%

Sili

ca F

ume

50%

Cla

ss C

Fly

Ash

Figure 11.85: Effectiveness of the K-M-A-J Model Predictions for Aggregate C2-SD

Figure 11.86: Comparison Between the 14-Day C 1260 expansions of Aggregates with 0% Replacement and with Predicted Replacements

Control

324

Results presented above indicate that replacing the cement with Class C fly ash,

Class F fly ash, or silica fume at levels predicted by the K-A-M-J’s model is

effective in mitigating the deleterious ASR expansions. The investigated alternatives

and aggregate combinations (Table 10.12) showed 14-day expansions below 0.10%.

It can be concluded that the model is effective in representing the actual expansions

that the bars are undergoing. The following conclusions about the effectiveness of

mitigation alternatives can be drawn:

1. Between 65% and 80% Class C fly as was needed to mitigate ASR in moderately

(M.R.) and highly (H.R.) reactive aggregates.

2. About 45% to 50% Class C fly ash was needed to mitigate ASR in slowly

reactive (S.R.) aggregates.

3. Between 30% and 40% Class F fly ash was needed to mitigate ASR in M.R. and

H.R. aggregates.

4. Between 15% and 20% silica fume was needed to mitigate ASR in H.R., M.R.,

and S.R. aggregates.

It can be noticed that these levels are on the high side and higher than what is usually

used in the field.

1. Practically, the highest percentage of Class C fly ash used in the field is 35% of

the weight of cement. In order for Class C fly ash to be effective in mitigating

ASR, replacement levels from 45% to 80% by weight were required. These high

contents of Class C fly ash might be achieved if the ash was used to add fines to

the concrete mixture. It should be noted that A6-NM, which is the most reactive

aggregate investigated, required a 50% Class C fly ash content in order to

decrease the 14-day expansion below 0.10%, specifically 0.02%. As a result,

using 50% Class C fly ash could be used with the other less reactive aggregates.

2. Class F fly ash is usually used to replace 15% to 25% of the weight of cement.

The predicted range of 30% to 40% is on the high side and may not be very

325

practical for many concretes. These high levels might be achieved if adding the

ash as fine materials is an option.

3. Silica fume is usually used to replace 5% to 10% of the weight of cement. Using

between 15% and 20% silica fume will result in a high fine content concrete and

might not be practical.

11.14 ASTM C 1260 INVESTIGATION OF MITIGATION ALTERNATIVES: SUMMARY

The following Tables list the effective mitigation alternatives for each aggregate.

These results were generated using the ASTM C 1260 procedures.

326

Table 11.29: Effective ASR Mitigation Alternatives When Evaluating Aggregates Using ASTM C 1260 with 1N NaOH Solution (1.5% Na2Oequiv.)

Cementitious Material

Aggregate, 14-day expansion, C 1260 Classification A6-NM 0.91% (H.R.)

A4-ID 0.79% (H.R.)

A2-WY 0.29% (H.R.)

C2-SD 0.17% (S.R.)

B4-VA 0.15% (S.R.)

E2-IA 0.42% (H.R.)

Minimum Replacement Levels by Weight of Cement Calcined

Clay 25% 25% 25% 17% 17% 25%

Granulated Slag 70% 55% 55% 40% 55% 55%

Class F Fly Ash 40% 25% 25% 15% 25% 25%

Silica Fume 10% 10%

Air Entrainment 4%

Class C Fly Ash 50% 50% 50% 35% 35% 50%

Chemical Admixture Minimum LiNO3 Volume (weight) per 1 kg of Na2Oequiv.

Lithium Nitrate 4.6 L

(5.5 kg) 4.6 L

(5.5 kg) 4.6 L

(5.5 kg) 4.6 L

(5.5 kg) Shaded Areas = Alternative could not be used

327

Table 11.30: Effective ASR Mitigation Alternatives for Highly Reactive Aggregate A6-NM (C1260 14-day of 0.92%) Evaluated Using C 1260 with

0.75N, 0.50N, & 0.35N NaOH Solutions

Cementitious Material

Minimum Replacement Levels by Weight of Cement Highly Reactive Aggregate A6-NM

1N NaOH (1.5%Na2Oequiv.)

0.75N NaOH (1.15%Na2Oequiv.)

0.50N NaOH (0.81%Na2Oequiv.)

0.35N NaOH (0.60%Na2Oequiv.)

Calcined Clay 25% 25% 17% 17%

Granulated Slag 70% 55% 50% 50%

Class F Fly Ash 40% 25% 20% 20%

Silica Fume 10% 10%

Class C Fly Ash 50% 50% 35% 35%

Chemical Admixture

Minimum LiNO3 Volume (weight) per 1 kg of Na2Oequiv. Highly Reactive Aggregate A6-NM

1N NaOH (1.5%Na2Oequiv.)

0.75N NaOH (1.15%Na2Oequiv.)

0.50N NaOH (0.81%Na2Oequiv.)

0.35N NaOH (0.60%Na2Oequiv.)

Lithium Nitrate 3.5 L (4.18 kg) 3.5 L (4.18 kg)

Air Entrainment

Shaded Areas = Alternative could not be used

11.15 COMPARISON OF THE MITIGATION ALTERNATIVE

Figures 11.87 through 11.92 provide a comparison between the effectiveness of

each of the investigated ASR mitigation alternatives for all six aggregates tested. As

can be seen in these figures, the effectiveness of the mitigation depended on the

aggregates. It seems that using 70% slag resulted in the lowest 14-day expansions for

all aggregates, followed by 25% calcined clay.

328

Highly Reactive Aggregate A6-NM

0 0.2 0.4 0.6 0.8 1

No Mitigation5% Silica Fume

21g LiNO328g LiNO3

20% Class C Fly Ash15% Class F Fly Ash

40% Slag27.5% Class C Fly

60g LiNO335% Class C Fly Ash

10% Silica Fume17% Calcined Clay

55% Slag25% Class F Fly Ash

25% Calcined Clay70%Slag

Miti

gatio

n A

ltern

ativ

e

14-Day Expansion, %

Highly Reactive Aggregate A4-ID

0 0.2 0.4 0.6 0.8 1

No Mitigation5% Silica Fume

21g LiNO328g LiNO3

20% Class C Fly Ash40% Slag

15% Class F Fly Ash27.5% Class C Fly

60g LiNO335% Class C Fly Ash

17% Calcined Clay10% Silica Fume

25% Class F Fly Ash55% Slag

25% Calcined Clay70%Slag

Miti

gatio

n A

ltern

ativ

e

14-Day Expansion, %

Figure 11.87: Mitigation Alternatives Used with Aggregate A6-NM

Best

Worst

Figure 11.88: Mitigation Alternatives Used with Aggregate A4-ID

Best

Worst

329

Highly Reactive Aggregate A2-WY

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

No Mitigation5% Silica Fume

20% Class C Fly Ash40% Slag

15% Class F Fly Ash27.5% Class C Fly

10% Silica Fume35% Class C Fly Ash

17% Calcined Clay21g LiNO3

55% Slag28g LiNO3

25% Class F Fly Ash25% Calcined Clay

60g LiNO370%Slag

Miti

gatio

n A

ltern

ativ

e

14-Day Expansion, %

Highly Reactive Aggregate C2-SD

0 0.05 0.1 0.15 0.2

No Mitigation20% Class C Fly Ash

5% Silica Fume21g LiNO3

40% Slag15% Class F Fly Ash

27.5% Class C Fly Ash28g LiNO3

10% Silica Fume35% Class C Fly Ash

55% Slag17% Calcined Clay

25% Class F Fly Ash60g LiNO3

25% Calcined Clay70%Slag

Miti

gatio

n A

ltern

ativ

e

14-Day Expansion, %

Figure 11.89: Mitigation Alternatives Used with Aggregate A2-WY

Best

Worst

Figure 11.90: Mitigation Alternatives Used with Aggregate C2-SD

Best

Worst

330

Highly Reactive Aggregate B4-VA

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16

No Mitigation20% Class C Fly Ash

5% Silica Fume21g LiNO3

27.5% Class C Fly Ash15% Class F Fly Ash

28g LiNO335% Class C Fly Ash

10% Silica Fume40% Slag

25% Class F Fly Ash60g LiNO3

17% Calcined Clay55% Slag

25% Calcined Clay70%Slag

Miti

gatio

n A

ltern

ativ

e

14-Day Expansion, %

Highly Reactive Aggregate E2-IA

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

No Mitigation20% Class C Fly Ash

5% Silica Fume15% Class F Fly Ash

27.5% Class C Fly Ash40% Slag

10% Silica Fume35% Class C Fly Ash

17% Calcined Clay55% Slag

21g LiNO328g LiNO3

25% Class F Fly Ash60g LiNO3

70%Slag25% Calcined Clay

Miti

gatio

n A

ltern

ativ

e

14-Day Expansion, %

Figure 11.91: Mitigation Alternatives Used with Aggregate B4-VA

Best

Worst

Figure 11.92: Mitigation Alternatives Used with Aggregate E2-IA

Best

Worst

331

CHAPTER TWELVE

INVESTIGATION OF MITIGATION ALTERNATIVES USING ASTM C 1293 AND ACCELERATED ASTM C 1293

12.1 INTRODUCTION

ASTM C 1293 and accelerated C 1293 were used to evaluate the effects of Class

C fly ash, Class F fly ash, silica fume, granulated slag, calcined clay, lithium nitrate

(LiNO3), air content, and cement alkali content on the ASR reactivity of selected

aggregates. A summary of the investigation is presented in Figure 12.1.

ASTM C 1293 is a concrete prism test that consists of storing three 3-in. x 3-in. x

11-in. concrete prisms over water, at 100% relative humidity, in a sealed container

with wicks on the sides, and at 380C. A cement content of 708 ± 17 lb/yd3 is required

and the alkali content of the cement is increased to 1.25% Na2Oequiv. by adding

NaOH to the mixing water. The accelerated C 1293 test consists of performing the

same procedures; however, the prisms are stored in containers at 600C. Results of the

investigation of these modified procedures were presented and discussed in Chapter

10 where it was shown that these procedures produced results within a period of 3

months that are similar to the C 1293 results after 12 months. Figure 10.16 shows the

high correlation between the results of both tests (R2 = 0.98).

A list of aggregates used for investigating mitigation alternatives using both C

1260 and C 1293 is included in Table 12.1. For investigating mitigation alternatives

using C 1293 one aggregate from each reactivity category was chosen. Three

aggregates were chosen for these investigations: A4-ID (highly reactive C 1260 and

C 1293), A2-WY (moderately reactive C 1260 and C 1293), and C2-SD (slowly

reactive C 1260 and C 1293). E2-IA was found to be innocuous when tested in

accordance to C 1293 and as a result was not included in the C 1293 investigation

but was used with the accelerated C 1293.

332

Class C Fly Ash 20%, 27.5%, 35%

Control

Class F Fly Ash 15%, 25%

Silica Fume 5%, 10%

Granulated Slag 25%, 55%, 70%

Calcined Clay 17%, 25%

Lithium Nitrate 3.5L, 4.6L, 10L

Air Entrainment 2-4%, 6-8%

Low Alkali Cement Content

0.6%, 0.90%, 1.25%

ASTM C 1293 - Concrete prisms - Alkali content 1.25% - Cement: 708 ± 17 lb/yd3 - W/C = 0.45 - Store prisms over water - Container with Wicks - 100% R.H. - Container stored at 380C

Accelerated ASTM C 1293

- Concrete prisms - Alkali content 1.25% - Cement: 708 ± 17 lb/yd3 - W/C = 0.45 - Store prisms over water - Container with Wicks - 100% R.H. - Container stored at 600C

ASTM C 1293 2-year (104-weeks)

Expansion of 0.040%

Accelerated ASTM C 1293

6-month (26-weeks) Expansion of

0.040%

ASTM C 1293 one-year (52-

weeks) Expansion of 0.040%

Accelerated ASTM C 1293

3-month (13-weeks) Expansion of

0.040%

Failure Criteria Concrete Samples Testing Method

Figure 12.1: Summary of the Investigation of Mitigation Alternatives Using C 1293 and Accelerated C 1293

333

Table 12.1: Aggregates Used for Mitigation Alternative Investigation Original (Non-Mitigation Study) Results Mitigation Study

Aggregate ID

14-Day C 1260

Expansion

One-Year C 1293

Expansion

3-month Accelerated 600C C 1293 Expansion

Aggregate Used for C 1260

Investigation

Aggregate Used for C 1293

Investigation

Aggregate Used for Modified C 1293

Investigation

A6-NM 0.91% (H.R.)

0.308% (H.R.)

0.427% (H.R.)

A4-ID 0.79% (H.R.)

0.305% (H.R.)

0.467% (H.R.)

A2-WY 0.29% (H.R.)

0.107% (H.R.)

0.072% (H.R.)

C2-SD 0.17% (S.R.)

0.043% (S.R.)

0.059% (S.R.)

B4-VA 0.15% (S.R.)

0.040% (S.R.)

0.043% (S.R.)

E2-IA 0.42% (H.R.)

0.025% (Innocuous)

0.024% (Innocuous)

= Aggregate Used Using These procedures H.R. = Highly Reactive = C 1260 14-day expansion > 0.20% = C 1293 1-year, Modified C 1293 3-month expansion > 0.070% S.R. = Slowly Reactive = 0.10% < C 1260 14-day expansion < 0.20% = 0.040% < C 1293 One-Year expansion < 0.070% = 0.040% < Modified C 1293 3-month expansion <0.070%

Innocuous = C 1260 14-day expansion < 0.10%

Based on C 1293, an alternative is considered effective if it decreases the 52-week

(one-year) expansions of concrete prisms below 0.040%. For evaluating pozzolanic

materials such as Class C fly ash, Class F fly ash, silica fume, slag, and calcined clay,

expansions should be monitored for a period of 104 weeks (two years) after which

expansions higher than 0.040% are considered reactive. This two-years limit was

proposed in the literature by researchers who found that the effect of pozzolanic

materials could not be assessed using the one-year limit. Expansions should be

monitored over a longer period of time and two years was found to be adequate

(Fournier 1992, Shayan 1992, and etc.). At this stage only the one-year expansions

are available. The remainder of the data will be available in a later report. Thus,

mitigation alternatives resulting in C 1293 expansions that exceed 0.040% after one-

year of testing are considered to be not effective in mitigating ASR.

334

Based on the accelerated C 1293 procedures (procedures of C 1293 performed at

600C instead of 380C), an alternative is considered effective if it decreases the 13-

week (3-month) expansions below 0.040%. For evaluating pozzolanic materials such

as Class C fly ash, Class F fly ash, silica fume, slag, and calcined clay, expansions

should be monitored for a period of 26 weeks (6 months) after which expansions

higher than 0.040% are considered reactive.

12.2 INVESTIGATION OF MITIGATION ALTERNATIVES USING C 1293

12.2.1 Effect of Class C Fly Ash Using C 1293

In order to investigate the effect of Class C fly ash on the expansions due to ASR,

three levels of cement replacement were investigated namely, 20, 27.5, and 35%. The

three aggregates identified in Table 12.1 were used to prepare the different mixtures

listed in Table 7.15. Results for these procedures are illustrated in Table 12.2 and

Figures 12.2 through 12.4. A comparison of the one-year expansions of the various

replacement levels is shown in Figure 12.5. As mentioned in Figure 12.1, a failure

limit of 0.040% at two years is used to evaluate the use of Class C fly ash.

From these results it can be noticed that expansions decreased with increasing

Class C fly ash contents. Replacing up to 35% of the weight of cement with Class C

fly ash decreased the one-year expansions of the highly reactive aggregates A4-ID to

0.034%, of the highly reactive aggregate A2-WY to 0.031%, and of the slowly

reactive aggregate to 0.016%, all of which are lower than 0.040%. But as mentioned

earlier, the effectiveness of Class C fly ash should be determined using the two-years

expansions, and, thus, it is not possible at this stage to determine the effect of 35%

Class C fly ash on ASR. However, it should be noted that the one-year expansions of

A4-ID and A2-WY when used with 35% Class C fly ash are very close to the limit of

0.040%. It is expected that these expansions will be higher than 0.040% after two-

years of testing.

335

Table 12.2: C 1293 Expansions Using Class C Fly Ash

Time Class C Fly Ash Replacement Level by Weight of Cement

0% 20% 27.5% 35% Aggregate A4-ID Expansions, %

1-week 0.019 -0.001 0.004 0.001 2-week 0.026 0.009 0.007 0.005 4-week 0.039 0.014 0.015 0.006 6-week 0.092 0.017 0.017 0.012 8-week 0.141 0.022 0.020 0.014 13-week 0.216 0.028 0.027 0.018 18-week 0.267 0.038 0.037 0.024 26-week 0.319 0.057 0.042 0.033 39-week 0.350 0.081 0.040 0.029 52-week 0.379 0.094 0.042 0.034

Aggregate A2-WY Expansions, % 1-week 0.003 0.011 0.004 0.001 2-week 0.005 0.013 0.024 0.005 4-week 0.009 0.023 0.026 0.011 6-week 0.010 0.023 0.029 0.011 8-week 0.013 0.027 0.034 0.014 13-week 0.018 0.032 0.037 0.017 18-week 0.028 0.045 0.047 0.026 26-week 0.067 0.050 0.051 0.030 39-week 0.109 0.049 0.049 0.027 52-week 0.107 0.058 0.057 0.031

Aggregate C2-SD Expansions, % 1-week 0.010 0.002 0.001 0.000 2-week 0.006 0.008 0.008 0.003 4-week 0.015 0.008 0.009 0.003 6-week 0.017 0.010 0.012 0.005 8-week 0.019 0.016 0.016 0.009 13-week 0.025 0.023 0.022 0.014 18-week 0.030 0.028 0.023 0.017 26-week 0.043 0.036 0.027 0.017 39-week 0.051 0.033 0.025 0.014 52-week 0.053 0.034 0.028 0.016

336

-0.040

0.000

0.040

0.080

0.120

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

ID-FAC 0%ID-FAC 20%ID-FAC 27.5%ID-FAC 35%

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

WY-FAC 0%WY-FAC 20%WY-FAC 27.5%WY-FAC 35%

Figure 12.2: Effect of Class C Fly Ash on C 1293 Expansions of Aggregate A4-ID

Figure 12.3: Effect of Class C Fly Ash on C 1293 Expansions of Aggregate A2-WY

337

-0.005

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0 4 8 1216 20 24 28 32 36 4044 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

SD-FAC 0%SD-FAC 20%SD-FAC 27.5%SD-FAC 35%

0.000

0.040

0.080

0.120

A4-ID A2-WY C2-SDAggregate Investigated

52-W

eek

(One

-Yea

r) E

xpan

sion

, % 0% Class C Fly Ash20% Class C Fly Ash27.5% Class C Fly Ash35% Class C Fly Ash

Figure 12.4: Effect of Class C Fly Ash on C 1293 Expansions of Aggregate C2-SD

Figure 12.5: Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Class C Fly Ash Replacement

338

Using 20% and 27.5% Class C fly ash with the highly reactive aggregates A4-ID

and A2-WY produced one-year expansions that are higher than 0.040% and were

concluded not effective in mitigating ASR for these aggregates. A summary of these

findings is included in Table 12.3.

Table 12.3: Effect of Class C Fly Ash on ASR Using C 1293

Aggregate ID

C 1293 One-Year Expansion

C 1293 Classification

Class C Fly Ash Replacement by Weight of Cement 20% 27.5% 35%

A4-ID 0.379% H.R. H.R. S.R. Inconclusive A2-WY 0.107% H.R. S.R. S.R. Inconclusive C2-SD 0.053% S.R. Inconclusive Inconclusive Inconclusive H.R. = Highly Reactive = C 1293 One-Year expansion > 0.070% S.R. = Slowly Reactive = 0.040% < C 1293 One-Year expansion < 0.070%

Innocuous = C 1293 One-Year expansion < 0.040% Inconclusive = C 1293 two-year expansion not available

12.2.2 Effect of Class F Fly Ash Using C 1293

In order to investigate the effect of Class F fly ash on the expansions due to ASR,

two levels of cement replacement were investigated, namely 15 and 25%. The three

aggregates identified in Table 12.1 were used to prepare the various mixtures listed

in Table 7.16. Expansion results for these procedures are illustrated in Table 12.3a

and Figures 12.6 through 12.8. A comparison of the one-year expansions of the

various replacement levels is shown in Figure 12.9. As shown in Figure 12.1, a

failure limit of 0.040% at two years was used to evaluate the use of Class F fly ash.

339

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.400

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

ID-FAF 0%ID-FAF 15%ID-FAF 25%

-0.020

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

WY-FAF 0%WY-FAF 15%WY-FAF 25%

Figure 12.6: Effect of Class F Fly Ash on C 1293 Expansions of Aggregate A4-ID

Figure 12.7: Effect of Class F Fly Ash on C 1293 Expansions of Aggregate A2-WY

340

-0.010

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

SD-FAF 0%SD-FAF 15%SD-FAF 25%

0.000

0.0400.080

0.1200.160

0.200

0.2400.280

0.3200.360

0.400

A4-ID A2-WY C2-SDAggregate Investigated

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

0% Class F Fly Ash15% Class F Fly Ash25% Class F Fly Ash

Figure 12.8: Effect of Class F Fly Ash on C 1293 Expansions of Aggregate C2-SD

Figure 12.9: Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Class F Fly Ash Replacement

341

Table 12.3a: C 1293 Expansions Using Class F Fly Ash

Time Class F Fly Ash Replacement Level by weight of Cement

0% 15% 25% Aggregate A4-ID Expansions, %

1-week 0.019 0.009 0.015 2-week 0.026 0.011 0.017 4-week 0.039 0.016 0.020 6-week 0.092 0.020 0.026 8-week 0.141 0.022 0.027 13-week 0.216 0.032 0.034 18-week 0.267 0.033 0.034 26-week 0.319 0.036 0.038 39-week 0.350 0.039 0.032 52-week 0.379 0.047 0.032

Aggregate A2-WY Expansions, % 1-week 0.003 0.009 0.000 2-week 0.005 0.009 -0.003 4-week 0.009 0.012 0.000 6-week 0.010 0.021 0.003 8-week 0.013 0.020 0.005 13-week 0.018 0.029 0.013 18-week 0.028 0.030 0.013 26-week 0.067 0.034 0.018 39-week 0.109 0.032 0.014 52-week 0.107 0.043 0.017

Aggregate C2-SD Expansions, % 1-week 0.010 0.003 -0.005 2-week 0.006 0.008 0.000 4-week 0.015 0.009 0.002 6-week 0.017 0.015 0.004 8-week 0.019 0.016 0.007 13-week 0.025 0.017 0.007 18-week 0.030 0.024 0.012 26-week 0.043 0.032 0.016 39-week 0.051 0.030 0.015 52-week 0.053 0.035 0.019

342

From these results, it can be noted that increasing the level of Class F fly ash

caused a decrease in the one-year expansion of concrete prisms. It was not possible

to determine whether Class F fly ash should be considered effective in mitigating

ASR using the one-year expansions. This can be accomplished by using the

accelerated C 1293 results or the two-year C 1293 results. Observation on the results

are summarized in Table 12.4

Table 12.4: Effect of Class F Fly Ash on ASR Using C 1293

Aggregate ID

C 1293 One-Year Expansion

C 1293 Classification

Class F Fly Ash Replacement by weight of

Cement 15% 25%

A4-ID 0.379% H.R. S.R. Inconclusive A2-WY 0.107% H.R. S.R. Inconclusive C2-SD 0.053% S.R. Inconclusive Inconclusive H.R. = Highly Reactive = C 1293 one-year expansion > 0.070% S.R. = Slowly Reactive = 0.040% < C 1293 one-year expansion < 0.070%

Innocuous = C 1293 one-year expansion < 0.040% Inconclusive = C 1293 two-year expansion not available

12.2.3 Effect of Silica Fume Using C 1293

In order to investigate the effect of silica fume on the expansions due to ASR, two

levels of cement replacement were investigated, namely 5 and 10%. The three

aggregates identified in Table 12.1 were used to prepare the various mixtures listed

in Table 7.14. Results for these procedures are illustrated in Table 12.5 and Figures

12.10 through 12.12. A comparison of the one-year expansions of the various

replacement levels is shown in Figure 12.13. As mentioned in Figure 12.1, a failure

limit of 0.040% at two years was used to evaluate the use of silica fume.

343

Table 12.5: C 1293 Expansions Using Silica Fume

Time Silica Fume Replacement Level by Weight of Cement

0% 5% 10% Aggregate A4-ID, Expansion, %

1-week 0.019 0.018 0.008 2-week 0.026 0.020 0.005 4-week 0.039 0.025 0.014 6-week 0.092 0.028 0.016 8-week 0.141 0.031 0.015 13-week 0.216 0.034 0.022 18-week 0.267 0.039 0.025 26-week 0.319 0.043 0.026 39-week 0.350 0.043 0.027 52-week 0.379 0.054 0.033

Aggregate A2-WY Expansions, % 1-week 0.003 0.008 0.005 2-week 0.005 0.011 0.007 4-week 0.009 0.015 0.011 6-week 0.010 0.016 0.011 8-week 0.013 0.020 0.014 13-week 0.018 0.024 0.015 18-week 0.028 0.029 0.022 26-week 0.067 0.037 0.025 39-week 0.109 0.033 0.027 52-week 0.107 0.040 0.028

Aggregate C2-SD Expansions, % 1-week 0.010 0.014 0.001 2-week 0.006 0.015 0.006 4-week 0.015 0.018 0.002 6-week 0.017 0.021 0.002 8-week 0.019 0.022 0.005 13-week 0.025 0.029 0.007 18-week 0.030 0.036 0.012 26-week 0.043 0.040 0.020 39-week 0.051 0.043 0.018 52-week 0.053 0.041 0.016

344

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.400

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

ID-SF 0%ID-SF 5%ID-SF 10%

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

WY-SF 0%WY-SF 5%WY-SF 10%

Figure 12.10: Effect of Silica Fume on C 1293 Expansions of Aggregate A4-ID

Figure 12.11: Effect of Silica Fume on C 1293 Expansions of Aggregate A2-WY

345

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

SD-SF 0%SD-SF 5%SD-SF 10%

0.000

0.0400.080

0.1200.160

0.200

0.2400.280

0.3200.360

0.400

A4-ID A2-WY C2-SDAggregate Investigated

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

0% Silica Fume5% Silica Fume10% Silica Fume

Figure 12.12: Effect of Silica Fume on C 1293 Expansions of Aggregate C2-SD

Figure 12.13: Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Silica Fume Replacement

346

An examination of these results is presented in Table 12.6 where it can be seen

that using 5% silica fume by mass was not effective with any of the aggregates in

decreasing the one-year expansions below the limit of 0.040%. The effect of using

10% silica fume by mass could not be determined using the one-year criterion. This

is accomplished using the accelerated C 1293. it should be noted that one-year

expansions decreased as the silica fume dosage increased.

Table 12.6: Effect of Silica Fume on ASR Using C 1293

Aggregate ID

C 1293 One-Year Expansion

C 1293 Classification

Silica Fume Replacement by weight of

Cement 5% 10%

A4-ID 0.379% H.R. S.R. Inconclusive A2-WY 0.107% H.R. S.R. Inconclusive C2-SD 0.053% S.R. S.R. Inconclusive H.R. = Highly Reactive = C 1293 one-year expansion > 0.070% S.R. = Slowly Reactive = 0.040% < C 1293 one-year expansion < 0.070%

Innocuous = C 1293 one-year expansion < 0.040% Inconclusive = C 1293 two-year expansion not available

12.2.4 Effect of Granulated Slag Using C 1293

In order to investigate the effect of granulated slag on the expansions due to ASR,

three levels of cement replacement were investigated, namely 25, 55, and 70%. The

three aggregates identified in Table 12.1 were used to prepare the various mixtures

listed in Table 7.17. Results for these procedures are illustrated in Table 12.7 and

Figures 12.14 through 12.16. A comparison of the one-year expansions of the various

replacement levels is shown in Figure 12.17. As mentioned in Figure 12.1, a failure

limit of 0.040% at two years was used to evaluate the use of granulated slag.

347

Table 12.7: C 1293 Expansions Using Granulated Slag

Time Granulated Slag Replacement Level by Weight of Cement

0% 25% 55% 70% Aggregate A4-ID Expansions, %

1-week 0.019 0.004 -0.001 0.006 2-week 0.026 0.008 0.004 0.008 4-week 0.039 0.016 0.002 0.014 6-week 0.092 0.022 0.004 0.015 8-week 0.141 0.025 0.003 0.016 13-week 0.216 0.065 0.011 0.024 18-week 0.267 0.167 0.014 0.026 26-week 0.319 0.277 0.014 0.026 39-week 0.350 0.345 0.014 0.023 52-week 0.379 0.363 0.021 0.025

Aggregate A2-WY Expansions, % 1-week 0.003 0.003 0.002 0.001 2-week 0.005 0.004 0.004 0.002 4-week 0.009 0.011 0.003 0.002 6-week 0.010 0.015 0.006 0.003 8-week 0.013 0.021 0.011 0.006 13-week 0.018 0.027 0.016 0.009 18-week 0.028 0.031 0.018 0.014 26-week 0.067 0.036 0.019 0.017 39-week 0.109 0.036 0.018 0.010 52-week 0.107 0.043 0.021 0.017

Aggregate C2-SD Expansions, % 1-week 0.010 0.006 0.000 0.003 2-week 0.006 0.009 0.003 0.007 4-week 0.015 0.016 0.007 0.010 6-week 0.017 0.015 0.013 0.012 8-week 0.019 0.020 0.013 0.011 13-week 0.025 0.026 0.017 0.018 18-week 0.030 0.032 0.019 0.021 26-week 0.043 0.036 0.021 0.019 39-week 0.051 0.033 0.023 0.017 52-week 0.053 0.045 0.022 0.017

348

-0.0400.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.400

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

ID-SL 0%ID-SL 25%ID-SL 55%ID-SL 70%

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

WY-SL 0%WY-SL 25%WY-SL 55%WY-SL 70%

Figure 12.14: Effect of Slag on C 1293 Expansions of Aggregate A4-ID

Figure 12.15: Effect of Slag on C 1293 Expansions of Aggregate A2-WY

349

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

SD-SL 0%SD-SL 25%SD-SL 55%SD-SL 70%

0.000

0.0400.080

0.1200.160

0.200

0.2400.280

0.3200.360

0.400

A4-ID A2-WY C2-SDAggregate Investigated

52-W

eek

(One

-Yea

r) E

xpan

sion

, % 0% Slag25% Slag55% Slag70% Slag

Figure 12.16: Effect of Slag on C 1293 Expansions of Aggregate C2-SD

Figure 12.17: Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Slag Replacement

350

An examination of these results is presented in Table 12.8 where it can be seen

that Replacing 25% of the weight of cement with granulated slag was not effective

with any of the aggregates in decreasing the one-year expansions below the limit of

0.040%. The effect of using 55 and 70% slag by mass could not be determined using

the one-year criterion. This is accomplished using the accelerated C 1293. It should

be noted that for all three aggregates, the one-year expansions decreased as the

percentage of slag in the mixture increased.

Table 12.8: Effect of Granulated Slag on ASR Using C 1293

Aggregate ID

C 1293 One-Year Expansion

C 1293 Classification

Granulated Slag Replacement by Weight of Cement 25% 55% 70%

A4-ID 0.379% H.R. H.R. Inconclusive Inconclusive A2-WY 0.107% H.R. S.R. Inconclusive Inconclusive C2-SD 0.053% S.R. S.R. Inconclusive Inconclusive H.R. = Highly Reactive = C 1293 one-year expansion > 0.070% S.R. = Slowly Reactive = 0.040% < C 1293 one-year expansion < 0.070%

Innocuous = C 1293 one-year expansion < 0.040% Inconclusive = C 1293 two-year expansion not available

12.2.5 Effect of Calcined Clay Using C 1293

In order to investigate the effect of calcined clay on the expansions due to ASR,

two levels of cement replacement were investigated, namely 17 and 25%. The three

aggregates identified in Table 12.1 were used to prepare the various mixtures listed

in Table 7.18. Results for these procedures are illustrated in Table 12.9 and Figures

12.18 through 12.20. A comparison of the one-year expansions of the various

replacement levels is shown in Figure 12.21. As mentioned in Figure 12.1, a failure

limit of 0.040% at two years was used to evaluate the use of calcined clay.

351

Table 12.9: C 1293 Expansions Using Calcined Clay

Time Calcined Clay Replacement Level by Weight of Cement

0% 17% 25% Aggregate A4-ID, Expansion, %

1-week 0.019 0.010 -0.004 2-week 0.026 0.011 0.002 4-week 0.039 0.017 0.006 6-week 0.092 0.017 0.007 8-week 0.141 0.020 0.008 13-week 0.216 0.025 0.011 18-week 0.267 0.027 0.014 26-week 0.319 0.024 0.010 39-week 0.350 0.028 0.012 52-week 0.379 0.030 0.017

Aggregate A2-WY Expansions, % 1-week 0.003 0.003 -0.001 2-week 0.005 0.012 0.003 4-week 0.009 0.012 0.004 6-week 0.010 0.017 0.008 8-week 0.013 0.019 0.011 13-week 0.018 0.023 0.015 18-week 0.028 0.026 0.017 26-week 0.067 0.019 0.013 39-week 0.109 0.026 0.014 52-week 0.107 0.029 0.016

Aggregate C2-SD Expansions, % 1-week 0.010 0.000 0.000 2-week 0.006 0.002 0.000 4-week 0.015 0.000 0.003 6-week 0.017 0.006 0.006 8-week 0.019 0.006 0.006 13-week 0.025 0.010 0.005 18-week 0.030 0.011 0.013 26-week 0.043 0.007 0.007 39-week 0.051 0.011 0.013 52-week 0.053 0.013 0.011

352

-0.0400.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.400

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

ID-CC 0%ID-CC 17%ID-CC 25%

-0.020

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

WY-CC 0%WY-CC 17%WY-CC 25%

Figure 12.18: Effect of Calcined Clay on C 1293 Expansions of Aggregate A4-ID

Figure 12.19: Effect of Calcined Clay on C 1293 Expansions of Aggregate A2-WY

353

-0.010

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

SD-CC 0%SD-CC 17%SD-CC 25%

0.000

0.0400.080

0.1200.160

0.200

0.2400.280

0.3200.360

0.400

A4-ID A2-WY C2-SDAggregate Investigated

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

0% Calcined Clay17% Clacined Clay25% Calcined Clay

Figure 12.20: Effect of Calcined Clay on C 1293 Expansions of Aggregate C2-SD

Figure 12.21: Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Calcined Clay Replacement

354

Observations deducted from these results are presented in Table 12.10 where it

can be seen that the effect of using calcined clay could not be determined using the

one-year criterion. This is accomplished using the accelerated C 1293. It should be

noted, that the one-year expansions decreased as the percentage of calcined clay

increased.

Table 12.10: Effect of Calcined Clay on ASR Using C 1293

Aggregate ID

C 1293 One-Year Expansion

C 1293 Classification

Calcined Clay Replacement by weight of

Cement 17% 25%

A4-ID 0.379% H.R. Inconclusive Inconclusive A2-WY 0.107% H.R. Inconclusive Inconclusive C2-SD 0.053% S.R. Inconclusive Inconclusive H.R. = Highly Reactive = C 1293 one-year expansion > 0.070% S.R. = Slowly Reactive = 0.040% < C 1293 one-year expansion < 0.070%

Innocuous = C 1293 one-year expansion < 0.040% Inconclusive = C 1293 two-year expansion not available

355

12.2.6 Effect of Lithium Nitrate (LiNO3) Using C 1293

In order to investigate the effect of LiNO3 on the expansions due to ASR, a

volume of the mixing water was replaced with a LiNO3 solution. The replaced

volume of water was equal to 85% of the volume of LiNO3 added. The dosages of

LiNO3 were as follows:

1. 3.5 liters of LiNO3 per 1 kg of Na2O in the mixture (315 g of LiNO3 for concrete

mixtures)

2. 4.6 liters of LiNO3 per 1 kg of Na2O in the mixture (495 g of LiNO3 for concrete

mixtures)

3. 10.0 liters of LiNO3 per 1 kg of Na2O in the mixture (900 g of LiNO3 for

concrete mixtures)

Mixture proportions were listed in Table 7.19. Results for these procedures are

illustrated in Table 12.11 and Figures 12.22 through 12.24. A comparison of the one-

year expansions of the various lithium dosages is shown in Figure 12.25. As

mentioned in Figure 12.1, a failure limit of 0.040% at one year is used to evaluate the

use of lithium nitrate.

356

Table 12.11: C 1293 Expansions Using Lithium Nitrate

Time Weight of Lithium Nitrate

0g 315g 495g 900g Aggregate A4-ID Expansions, %

1-week 0.019 0.003 0.007 0.007 2-week 0.026 0.007 0.012 0.007 4-week 0.039 0.013 0.017 0.014 6-week 0.092 0.015 0.020 0.016 8-week 0.141 0.021 0.023 0.018 13-week 0.216 0.028 0.025 0.022 18-week 0.267 0.035 0.027 0.022 26-week 0.319 0.054 0.025 0.022 39-week 0.350 0.067 0.026 0.027 52-week 0.379 0.074 0.024 0.027

Aggregate A2-WY Expansions, % 1-week 0.003 0.002 0.007 0.007 2-week 0.005 0.002 0.012 0.007 4-week 0.009 0.011 0.017 0.011 6-week 0.010 0.012 0.020 0.012 8-week 0.013 0.016 0.023 0.016 13-week 0.018 0.019 0.025 0.019 18-week 0.028 0.024 0.027 0.022 26-week 0.067 0.020 0.025 0.019 39-week 0.109 0.029 0.026 0.018 52-week 0.107 0.046 0.024 0.016

Aggregate C2-SD Expansions, % 1-week 0.010 0.007 0.002 0.001 2-week 0.006 0.016 0.010 0.009 4-week 0.015 0.020 0.013 0.012 6-week 0.017 0.019 0.013 0.010 8-week 0.019 0.024 0.016 0.014 13-week 0.025 0.029 0.022 0.019 18-week 0.030 0.029 0.024 0.017 26-week 0.043 0.029 0.020 0.014 39-week 0.051 0.032 0.027 0.023 52-week 0.053 0.041 0.023 0.018

357

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.400

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

ID-LI 0gID-LI 315gID-LI 495gID-LI 900g

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

WY-LI 0gWY-LI 315gWY-LI 495gWY-LI 900g

Figure 12.22: Effect of Lithium Nitrate on C 1293 Expansions of Aggregate A4-ID

Figure 12.23: Effect of Lithium Nitrate on C 1293 Expansions of Aggregate A2-WY

358

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

SD-LI 0gSD-LI 315gSD-LI 495gSD-LI 900g

0.000

0.0400.080

0.1200.160

0.200

0.2400.280

0.3200.360

0.400

A4-ID A2-WY C2-SDAggregate Investigated

52-W

eek

(One

-Yea

r) E

xpan

sion

, % 0g Lithim Nitrate315g Lithim Nitrate495g Lithim Nitrate900g Lithim Nitrate

Figure 12.24: Effect of Lithium Nitrate on C 1293 Expansions of Aggregate C2-SD

Figure 12.25: Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Levels of Lithium Nitrate

359

From these results, it can be seen that using 315g of lithium nitrate (3.5 L) to

replace part of the mixing water was not effective, with any of the three aggregates,

in decreasing the one-year expansions below 0.040%. All three aggregates required a

minimum of 495g (4.6 L) of LiNO3 in order to decrease the one-year expansions of

concrete prisms below 0.040%. As can be seen in Figure 12.25, minimal benefit in

decreasing the one-year expansions was obtained by increasing the LiNO3 dosage

from 495g (4.6 L) to 900g (10.0 L). In fact, for aggregate A4-ID, the one-year

expansion of concrete with 900g LiNO3 was slightly higher than the concrete with

495g (4.6 L) LiNO3; however, the 900g LiNO3 was still showing innocuous

expansions. Thus, for minimizing deleterious expansions due to ASR, a minimum of

495g (4.6 L) of LiNO3 was required to replace part of the mixing water (The

replaced volume of water was equal to 85% of the volume of LiNO3 added).

Additional LiNO3 might not be very beneficial. These observations are summarized

in Table 12.12.

Table 12.12: Effect of Lithium Nitrate on ASR Using C 1293

Aggregate ID

C 1293 One-Year Expansion

C 1293 Classification

Lithium Nitrate Weight

315 g 495 g 900 g

A4-ID 0.379% H.R. H.R. Innocuous Innocuous A2-WY 0.107% H.R. S.R. Innocuous Innocuous C2-SD 0.053% S.R. S.R. Innocuous Innocuous H.R. = Highly Reactive = C 1293 one-year expansion > 0.070% S.R. = Slowly Reactive = 0.040% < C 1293 one-year expansion < 0.070%

Innocuous = C 1293 one-year expansion < 0.040%

360

12.2.7 Effect of Air Entrainment Using C 1293

In order to investigate the effect of air entrainment (AE) on the expansions due to

ASR, two ranges of entrained air were investigated namely, between 2 and 4%

labeled AE 4% and between 6 and 8% labeled AE 8%. Entrained air refers to total air

content reduced by the entrapped air content. The three aggregates, mentioned Table

12.1, were used to prepare the different mixtures listed in Table 7.13. Results for

these procedures are illustrated in Figures 12.26 through 11.28 and Table 12.13. A

comparison between the one-year expansions of the different air levels is shown in

Figure 12.29.

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

ID-AE 0%ID-AE 2-4%ID-AE 6-8%

Figure 12.26: Effect of Air Entrainment on C 1293 Expansions of Aggregate A4-ID

361

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

WY-AE 0%WY-AE 2-4%WY-AE 6-8%

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56

Time, Weeks

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

SD-AE 0%SD-AE 4%SD-AE 8%

Figure 12.27: Effect of Air Entrainment on C 1293 Expansions of Aggregate A2-WY

Figure 12.28: Effect of Air Entrainment on C 1293 Expansions of Aggregate C2-SD

362

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

A4-ID A2-WY C2-SD

Aggregate Investigated

52-W

eek

(One

-Yea

r) E

xpan

sion

, %

0% Air2-4% Air6-8% Air

Figure 12.29: Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Air Entrainment Contents

363

Table 12.13: C 1293 Expansions Using Air Entrainment

Time Air Entrainment Content

0% 2 to 4% 6 to 8% Aggregate A4-ID, Expansion, %

1-week 0.019 0.005 0.004 2-week 0.026 0.018 0.011 4-week 0.039 0.027 0.023 6-week 0.092 0.038 0.034 8-week 0.141 0.058 0.041

13-week 0.216 0.127 0.069 18-week 0.267 0.193 0.100 26-week 0.319 0.281 0.162 39-week 0.350 0.310 0.223 52-week 0.379 0.382 0.267

Aggregate A2-WY Expansions, % 1-week 0.003 0.004 0.010 2-week 0.005 0.007 0.011 4-week 0.009 0.015 0.017 6-week 0.010 0.021 0.025 8-week 0.013 0.024 0.023

13-week 0.018 0.031 0.032 18-week 0.028 0.042 0.041 26-week 0.067 0.053 0.049 39-week 0.109 0.069 0.055 52-week 0.107 0.083 0.060

Aggregate C2-SD Expansions, % 1-week 0.010 0.011 0.012 2-week 0.006 0.010 0.011 4-week 0.015 0.012 0.014 6-week 0.017 0.016 0.014 8-week 0.019 0.019 0.017

13-week 0.025 0.028 0.023 18-week 0.030 0.033 0.028 26-week 0.043 0.044 0.040 39-week 0.051 0.049 0.045 52-week 0.053 0.052 0.042

364

An examination of these results generated the comments listed in Table 12.14

where it can be noted that using air entrainment to mitigate the alkali-silica reactivity

of aggregates investigated was not effective.

Table 12.14: Effect of Air Entrainment on ASR Using C 1293

Aggregate ID

C 1293 One-Year Expansion

C 1293 Classification

Air Entrainment Content 2 to 4% 6 to 8%

A4-ID 0.379% H.R. H.R. H.R. A2-WY 0.107% H.R. H.R. S.R. C2-SD 0.053% S.R. S.R. S.R. H.R. = Highly Reactive = C 1293 one-year expansion > 0.070% S.R. = Slowly Reactive = 0.040% < C 1293 one-year expansion < 0.070%

Innocuous = C 1293 one-year expansion < 0.040% Inconclusive = C 1293 two-year expansion not available

As can be seen in Figure 12.29, for aggregate A4-ID, concretes with 2 to 4% and

6 to 8% entrained air exhibited higher one-year expansions than the control concrete

with no entrained air. The concrete with 6 to 8% entrained air showed one-year

expansion lower than the concrete with 2 to 4%. For A2-WY and C2-SD, the one-

year expansions decreased as the entrained air content increased; however, the

expansions were still higher than 0.040%. Thus, using 2 to 4% entrained air has an

adverse effect on the mitigation of the alkali-silica reactivity of highly reactive

aggregates. Using 6 to 8% entrained air decreased the one-year expansions of all

aggregates, but not to safe limits. It can be concluded that air entrainment is not an

effective alternative for mitigating ASR.

In order to further proof the inadequacy of air entrainment in mitigating the alkali-

silica reactivity of aggregates, one highly reactive aggregate, A6-NM, was added to

the investigation and additional air entrainment levels were investigated as indicated

in Table 12.15.

365

Table 12.15: Additional C 1293 Expansions Using Air Entrainment

Time Air Entrainment Content

0 - 2% 2 – 4% 4 – 6% 6 – 8% Aggregate A6-NM Expansions, %

1-week 0.003 0.002 0.003 0.005 2-week 0.006 0.004 0.008 0.009 4-week 0.044 0.025 0.023 0.025 6-week 0.142 0.066 0.047 0.042 8-week 0.232 0.127 0.076 0.064

13-week 0.377 0.188 0.149 0.122 18-week 0.456 0.313 0.212 0.173 26-week 0.553 0.395 0.296 0.252 39-week 0.633 0.439 0.334 0.302 52-week 0.749 0.499 0.386 0.357

Aggregate A4-ID Expansions, % 1-week 0.005 0.005 -0.002 0.004 2-week 0.018 0.018 -0.002 0.011 4-week 0.028 0.027 0.002 0.023 6-week 0.054 0.038 0.012 0.034 8-week 0.097 0.058 0.024 0.041

13-week 0.209 0.127 0.077 0.069 18-week 0.286 0.193 0.134 0.100 26-week 0.353 0.281 0.211 0.162 39-week 0.400 0.310 0.261 0.223 52-week 0.455 0.382 0.301 0.267

Aggregate A2-WY Expansions, % 1-week 0.008 0.004 0.008 0.010 2-week 0.014 0.007 0.017 0.011 4-week 0.018 0.015 0.026 0.017 6-week 0.024 0.021 0.032 0.025 8-week 0.027 0.024 0.036 0.023

13-week 0.034 0.031 0.043 0.032 18-week 0.048 0.042 0.053 0.041 26-week 0.072 0.053 0.067 0.049 39-week 0.091 0.069 0.077 0.055 52-week 0.110 0.083 0.099 0.060

366

A comparison between the one-year expansions of the different aggregates and air

entrainment contents listed in Table 12.15 is included in Figure 12.30.

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

0.800

A6-NM A4-ID A2-WYAggregate Investigated

52-W

eek

(One

-Yea

r) E

xpan

sion

, % 0% Air0-2% Air2-4% Air4-6% Air 6-8% Air

It can be seen from Figure 12.30 that for concrete prisms made with the highly

reactive aggregates A6-NM and A4-ID, 4 to 6% entrained air was required to slightly

decrease the one-year expansions below the concrete with no entrained air. Lower

entrained air contents caused the one-year expansions to increase. With all three

aggregates, using up to 8% entrained air was not effective in decreasing the one-year

expansions of concrete prisms below the safe limit of 0.040%. Thus, air entrainment

could not be used to mitigate ASR.

Figure 12.30: Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Air Entrainment Contents of Table 12.15

367

12.3 COMPARISON BETWEEN ONE YEAR C 1293 RESULTS AND

13-WEEK ACCELERATED C 1293 RESULTS

The accelerated C 1293, consisting of performing the same procedure as the

standard C 1293 with the exception of storing the containers at 600C instead of 380C,

was also used to investigate the effectiveness of the different mitigation alternatives

listed in Figure 12.1. Detailed results for the accelerated C 1293 are presented in the

section 12.4. In this section, one-year expansions generated using C 1293 are

compared against the 13-week (3-month) expansions generated using the accelerated

C 1293 in order to demonstrate the effectiveness of the accelerated procedures in

producing results that are comparable to the standard C 1293. This is accomplished

in Figure 12.31 which plots the standard one-year expansions versus the accelerated

13-week expansions.

y = 0.8526x + 0.0034R2 = 0.9732

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

0.500

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55

13-Week Accelerated C 1293 Expansion, %

One

-Yea

r St

anda

rd C

129

3 E

xpan

sion

, %

Figure 12.31: Comparison Between the Standard One-Year Expansions and the Accelerated 13-Week Expansions of the Various Mitigation Alternatives

368

Figure 12.31 indicates that there is a strong relationship between the two

procedures and that the accelerated procedures can produce, with high confidence,

results that are very similar to the standard procedures. This is manifested by the high

correlation that exists between expansions generated by both procedures. This

evidence coupled with the argument proposed in Chapter 10 provide the basis for

being able to use the accelerated procedures to evaluate the effectiveness of the

mitigation alternatives. As mentioned in Figure 12.1, a limit of 0.040% at 13 weeks

(corresponding to one year in the standard procedure) is used to evaluate the

effectiveness of LiNO3 and air entrainment while a limit of 0.040% at 26 weeks

(corresponding to two years in the standard procedures) is used to evaluate the

effectiveness of Class C fly ash, Class F fly ash, silica fume, granulated slag, and

calcined clay.

12.4 INVESTIGATION OF MITIGATION ALTERNATIVES USING

ACCELERATED C 1293 RESULTS

The accelerated C 1293 procedures were used to evaluate the effectiveness of

the alternatives, listed in Figure 12.1, in mitigating the alkali-silica reactivity of

aggregates listed in Table 12.1. Concrete mixtures were proportioned using a reactive

aggregate in combination with an innocuous aggregate, a cement with an alkali

content of 0.9 ± 0.1%, and the alternative being investigated. The cement alkali

content was increased to 1.25% Na2Oequiv. by adding NaOH to the mixing water. A

cementitious materials content of 710 lb/yd3 and a water-cement ratio by mass of

0.45 were used for concrete proportioning. Each mixture was used to cast three 3-in.

x 3-in. x 11-in. concrete prisms which were moist cured for 24 hours while still in

molds. Prisms were then demolded, measured for their initial length, and stored over

water, in a sealed 6-gal bucket with wicks on the sides (100% R.H.). These

procedures were identical to the procedures of the standard C 1293. The only

exception was that the buckets were stored in an environmental room maintained at a

369

temperature of 60 ± 20C. Length expansions were monitored periodically over a

period of 26 weeks. The failure criteria used with these procedures are listed in

Figure 12.1.

12.4.1 Effect of Class C Fly Ash Using Accelerated C 1293

The effect of Class C fly ash on the expansions caused by ASR was evaluated

using the accelerated C 1293 procedures. Three levels of cement replacement were

investigated, namely 20, 27.5, and 35%. Four aggregates, identified in Table 12.1,

were used to prepare the different mixtures listed in Table 7.15 (these are the same

mixtures used for the standard C 1293). Results for these procedures are illustrated in

Table 12.16 and Figures 12.32 through 12.35. A comparison of the 26-week

expansions of the various replacement levels is shown in Figure 12.36. As mentioned

in Figure 12.1, a failure limit of 0.040% at 26 weeks was used to evaluate the use of

Class C fly ash.

0.0000.0500.1000.1500.2000.2500.3000.3500.4000.4500.500

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

ID-FAC 0%ID-FAC 20%ID-FAC 27.5%ID-FAC 35%

Figure 12.32: Effect of Class C Fly Ash on the Accelerated C 1293 Expansions of Aggregate A4-ID

370

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

WY-FAC 0%WY-FAC 20%WY-FAC 27.5%WY-FAC 35%

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

SD-FAC 0%SD-FAC 20%SD-FAC 27.5%SD-FAC 35%

Figure 12.33: Effect of Class C Fly Ash on the Accelerated C 1293 Expansions of Aggregate A2-WY

Figure 12.34: Effect of Class C Fly Ash on the Accelerated C 1293 Expansions of Aggregate C2-SD

371

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

IA-FAC 0%IA-FAC 20%IA-FAC 27.5%IA-FAC 35%

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.4400.480

A4-ID A2-WY C2-SD E2-IAAggregate Investigated

26-W

eek

(6-M

onth

) Exp

ansi

on, % 0% Class C Fly Ash

20% Class C Fly Ash27.5% Class C Fly Ash35% Class C Fly Ash

Figure 12.35: Effect of Class C Fly Ash on the Accelerated C 1293 Expansions of Aggregate E2-IA

Figure 12.36: Comparison Between the 26-Week Expansions Generated Using the Accelerated C 1293 Procedures and the Different Class C Fly Ash

Replacement Levels

372

Table 12.16: Accelerated C 1293 Expansions Using Class C Fly Ash

Time Class C Fly Ash Replacement Level by Weight of Cement

0% 20% 27.5% 35% Aggregate A4-ID Expansions, %

1-week 0.058 0.023 0.009 0.007 2-week 0.141 0.036 0.019 0.011 4-week 0.324 0.064 0.032 0.017 8-week 0.353 0.085 0.040 0.025 13-week 0.396 0.101 0.050 0.038 18-week 0.424 0.108 0.061 0.045 26-week 0.440 0.117 0.069 0.050

Aggregate A2-WY Expansions, % 1-week 0.027 0.010 0.008 0.002 2-week 0.038 0.015 0.019 0.005 4-week 0.062 0.031 0.035 0.010 8-week 0.077 0.042 0.049 0.019 13-week 0.083 0.053 0.050 0.040 18-week 0.088 0.072 0.071 0.050 26-week 0.096 0.089 0.083 0.062

Aggregate C2-SD Expansions, % 1-week 0.014 0.001 0.001 0.000 2-week 0.016 0.005 0.004 0.004 4-week 0.029 0.012 0.010 0.007 8-week 0.050 0.025 0.020 0.011 13-week 0.059 0.044 0.032 0.020 18-week 0.063 0.050 0.047 0.025 26-week 0.071 0.062 0.052 0.030

Aggregate E2-IA Expansions, % 1-week 0.016 0.010 0.008 0.002 2-week 0.016 0.015 0.014 0.005 4-week 0.023 0.021 0.019 0.010 8-week 0.024 0.023 0.020 0.019 13-week 0.028 0.027 0.024 0.023 18-week 0.028 0.030 0.028 0.026 26-week 0.031 0.032 0.030 0.029

Observations related to these results are summarized in Table 12.17 where it can

be seen that replacing 25 and 27.5% of the weight of cement by Class C fly ash was

373

not effective in decreasing the 26-week expansions below 0.040% for any of A4-ID,

A2-WY, and C2-SD. Using 35% Class C fly ash was only effective with C2-SD and

not A4-ID and A2-WY. Aggregate E2-IA which was non-reactive in concrete made

with cement only, exhibited innocuous expansions also when 20, 27.5, and 35%

Class C fly ash was used to replace the cement by weight.

Table 12.17: Effect of Class C Fly Ash on ASR Using Accelerated C 1293

Aggregate ID

C 1293 One-Year Expansion

and Classification

Accelerated C 1293 13-Week Expansion and Classification

Class C Fly Ash Replacement by Weight of Cement

20% 27.5% 35%

A4-ID 0.379% Highly Reactive

0.396% Highly Reactive H.R. H.R. S.R.

A2-WY 0.107% Highly Reactive

0.083% Highly Reactive H.R. H.R. S.R.

C2-SD 0.053% Slowly Reactive

0.059% Slowly Reactive S.R. S.R. Innocuous

E2-IA 0.025% Non-Reactive

0.028% Non-Reactive Innocuous Innocuous Innocuous

H.R. = Accelerated C 1293 26-week expansion > 0.070% S.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

Innocuous = Accelerated C 1293 26-week expansion < 0.040%

12.4.2 Effect of Class F Fly Ash Using Accelerated C 1293

The effect of Class C fly ash on the expansions caused by ASR was evaluated

using the accelerated C 1293 procedures. Two levels of cement replacement were

investigated namely, 15 and 25%. Four aggregates, identified in Table 12.1, were

used to prepare the different mixtures listed in Table 7.16 (these are the same mixture

used for the standard C 1293). Results for these procedures are illustrated in Table

12.18 and Figures 12.37 through 12.40. A comparison between the 26-week

expansions of the various replacement levels is shown in Figure 12.41. As mentioned

in Figure 12.1, a failure limit of 0.040% at 26 weeks is used to evaluate the use of

Class F fly ash.

374

Table 12.18: Accelerated C 1293 Expansions Using Class F Fly Ash

Time Class F Fly Ash Replacement Level by weight of Cement

0% 15% 25% Aggregate A4-ID Expansions, %

1-week 0.058 0.004 0.001 2-week 0.141 0.010 0.005 4-week 0.324 0.019 0.012 8-week 0.353 0.030 0.021

13-week 0.396 0.059 0.042 18-week 0.424 0.065 0.052 26-week 0.440 0.080 0.065

Aggregate A2-WY Expansions, % 1-week 0.027 0.001 0.000 2-week 0.038 0.008 0.003 4-week 0.062 0.015 0.005 8-week 0.077 0.033 0.008

13-week 0.083 0.044 0.011 18-week 0.088 0.051 0.019 26-week 0.096 0.062 0.028

Aggregate C2-SD Expansions, % 1-week 0.014 0.003 0.001 2-week 0.016 0.005 0.004 4-week 0.029 0.010 0.010 8-week 0.050 0.021 0.015

13-week 0.059 0.040 0.021 18-week 0.063 0.048 0.025 26-week 0.071 0.053 0.029

Aggregate E2-IA Expansions, % 1-week 0.016 0.010 0.008 2-week 0.016 0.013 0.011 4-week 0.023 0.019 0.017 8-week 0.024 0.023 0.019

13-week 0.028 0.024 0.022 18-week 0.028 0.027 0.024 26-week 0.031 0.030 0.029

375

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.4400.480

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eeks

(6-M

onth

) Exp

ansi

on, %

ID-FAF 0%ID-FAF 15%ID-FAF 25%

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eeks

(6-M

onth

) Exp

ansi

on, %

WY-FAF 0%WY-FAF 15%WY-FAF 25%

Figure 12.37: Effect of Class F Fly Ash on the Accelerated C 1293 Expansions of Aggregate A4-ID

Figure 12.38: Effect of Class F Fly Ash on the Accelerated C 1293 Expansions of Aggregate A2-WY

376

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eeks

(6-M

onth

) Exp

ansi

on, %

SD-FAF 0%SD-FAF 15%SD-FAF 25%

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eeks

(6-M

onth

) Exp

ansi

on, %

IA-FAF 0%IA-FAF 15%IA-FAF 25%

Figure 12.39: Effect of Class F Fly Ash on the Accelerated C 1293 Expansions of Aggregate C2-SD

Figure 12.40: Effect of Class F Fly Ash on the Accelerated C 1293 Expansions of Aggregate E2-IA

377

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.4400.480

A4-ID A2-WY C2-SD E2-IAAggregate Investigated

26-W

eek

(6-M

onth

) Exp

ansi

on, %

0% Class F Fly Ash15% Class F Fly Ash25% Class F Fly Ash

Observations related to these results are summarized in Table 12.19 where it can

be seen that replacing 15% of the weight of cement by Class F fly ash was not

effective in decreasing the 26-week expansions below 0.040% for any of A4-ID, A2-

WY, and C2-SD. Using 25% Class F fly ash was effective with A2-WY and C2-SD

but not A4-ID. Aggregate E2-IA, which was non-reactive in concrete made with

cement only, exhibited innocuous expansions also when 15 and 25% Class C fly ash

was used to replace the cement by weight.

Figure 12.41: Comparison Between the 26-Week Expansions Generated Using the Accelerated C 1293 Procedures and the Different Class F Fly Ash

Replacement Levels

378

Table 12.19: Effect of Class F Fly Ash on ASR Using Accelerated C 1293

Aggregate ID

C 1293 One-Year Expansion

and Classification

Accelerated C 1293 13-Week Expansion and Classification

Class F Fly Ash Replacement by Weight of

Cement 15% 25%

A4-ID 0.379% Highly Reactive

0.396% Highly Reactive H.R. S.R.

A2-WY 0.107% Highly Reactive

0.083% Highly Reactive S.R. Innocuous

C2-SD 0.053% Slowly Reactive

0.059% Slowly Reactive S.R. Innocuous

E2-IA 0.025% Non-Reactive

0.028% Non-Reactive Innocuous Innocuous

H.R. = Accelerated C 1293 26-week expansion > 0.070% S.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

Innocuous = Accelerated C 1293 26-week expansion < 0.040%

12.4.3 Effect of Silica Fume Using Accelerated C 1293

The effect of silica fume on the expansions caused by ASR was evaluated using

the accelerated C 1293 procedures. Two levels of cement replacement were

investigated, namely 5 and 10%. Four aggregates, identified in Table 12.1, were used

to prepare the different mixtures listed in Table 7.14 (these are the same mixtures

used for the standard C 1293). Results for these procedures are illustrated in Table

12.20 and Figures 12.42 through 12.45. A comparison between the 26-week

expansions of the various replacement levels is shown in Figure 12.46. As mentioned

in Figure 12.1, a failure limit of 0.040% at 26 weeks was used to evaluate the use of

silica fume.

379

Table 12.20: Accelerated C 1293 Expansions Using Silica Fume

Time Silica Fume Replacement Level by weight of Cement

0% 5% 10% Aggregate A4-ID Expansions, %

1-week 0.058 0.004 0.002 2-week 0.141 0.010 0.006 4-week 0.324 0.028 0.013 8-week 0.353 0.042 0.020 13-week 0.396 0.079 0.041 18-week 0.424 0.088 0.049 26-week 0.440 0.099 0.055

Aggregate A2-WY Expansions, % 1-week 0.027 0.002 0.001 2-week 0.038 0.010 0.005 4-week 0.062 0.020 0.010 8-week 0.077 0.034 0.018 13-week 0.083 0.044 0.023 18-week 0.088 0.053 0.036 26-week 0.096 0.061 0.041

Aggregate C2-SD Expansions, % 1-week 0.014 0.005 0.000 2-week 0.016 0.011 0.004 4-week 0.029 0.020 0.010 8-week 0.050 0.031 0.018 13-week 0.059 0.040 0.019 18-week 0.063 0.047 0.025 26-week 0.071 0.052 0.031

Aggregate E2-IA Expansions, % 1-week 0.016 0.001 0.002 2-week 0.016 0.009 0.009 4-week 0.023 0.015 0.011 8-week 0.024 0.021 0.015 13-week 0.028 0.029 0.023 18-week 0.028 0.031 0.025 26-week 0.031 0.033 0.029

380

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.4400.480

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

ID-SF 0%ID-SF 5%ID-SF 10%

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

WY-SF 0%WY-SF 5%WY-SF 10%

Figure 12.42: Effect of Silica Fume on the Accelerated C 1293 Expansions of Aggregate A4-ID

Figure 12.43: Effect of Silica Fume on the Accelerated C 1293 Expansions of Aggregate A2-WY

381

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

SD-SF 0%SD-SF 5%SD-SF 10%

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

IA-SF 0%IA-SF 5%IA-SF 10%

Figure 12.44: Effect of Silica Fume on the Accelerated C 1293 Expansions of Aggregate C2-SD

Figure 12.45: Effect of Silica Fume on the Accelerated C 1293 Expansions of Aggregate E2-IA

382

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.4400.480

A4-ID A2-WY C2-SD E2-IAAggregate Investigated

26-W

eek

(6-M

onth

) Exp

ansi

on, %

0% Silica Fume5% Silica Fume10% Silica Fume

Observations related to these results are summarized in Table 12.21 where it can

be seen that replacing 5 and 10% of the weight of cement by silica fume was not

effective in decreasing the 26-week expansions below 0.040% for any of A4-ID and

A2-WY. Ten percent silica fume was needed to reduce the 26-week expansions of

aggregate C2-SD below 0.040%. Aggregate E2-IA, which was non-reactive in

concrete made with cement only, exhibited innocuous expansions also when 5 and

10% silica fume was used to replace the cement by weight.

Figure 12.46: Comparison Between the 26-Week Expansions Generated Using the Accelerated C 1293 Procedures and the Different Silica Fume

Replacement Levels

383

Table 12.21: Effect of Silica Fume on ASR Using Accelerated C 1293

Aggregate ID

C 1293 One-Year Expansion

and Classification

Accelerated C 1293 13-Week Expansion and Classification

Silica Fume Replacement by Weight of

Cement 5% 10%

A4-ID 0.379% Highly Reactive

0.396% Highly Reactive H.R. S.R.

A2-WY 0.107% Highly Reactive

0.083% Highly Reactive S.R. S.R.

C2-SD 0.053% Slowly Reactive

0.059% Slowly Reactive S.R. Innocuous

E2-IA 0.025% Non-Reactive

0.028% Non-Reactive Innocuous Innocuous

H.R. = Accelerated C 1293 26-week expansion > 0.070% S.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

Innocuous = Accelerated C 1293 26-week expansion < 0.040%

12.4.4 Effect of Granulated Slag Using Accelerated C 1293

The effect of granulated slag on the expansions caused by ASR was evaluated

using the accelerated C 1293 procedures. Three levels of cement replacement were

investigated, namely 25, 55, and 70%. Four aggregates, identified in Table 12.1,

were used to prepare the different mixtures listed in Table 7.17 (these are the same

mixtures used for the standard C 1293). Results for these procedures are illustrated in

Table 12.22 and Figures 12.47 through 12.50. A comparison between the 26-week

expansions of the various replacement levels is shown in Figure 12.51. As mentioned

in Figure 12.1, a failure limit of 0.040% at 26 weeks was used to evaluate the use of

granulated slag.

384

Table 12.22: Accelerated C 1293 Expansions Using Granulated Slag

Time Granulated Slag Replacement Level by Weight of Cement

0% 25% 55% 70% Aggregate A4-ID Expansions, %

1-week 0.058 0.035 0.005 0.007 2-week 0.141 0.078 0.009 0.010 4-week 0.324 0.193 0.013 0.015 8-week 0.353 0.267 0.020 0.021

13-week 0.396 0.355 0.026 0.026 18-week 0.424 0.360 0.029 0.022 26-week 0.440 0.365 0.033 0.031

Aggregate A2-WY Expansions, % 1-week 0.027 0.004 0.000 0.000 2-week 0.038 0.008 0.001 0.003 4-week 0.062 0.019 0.005 0.008 8-week 0.077 0.031 0.011 0.011

13-week 0.083 0.048 0.018 0.015 18-week 0.088 0.053 0.023 0.025 26-week 0.096 0.063 0.026 0.029

Aggregate C2-SD Expansions, % 1-week 0.014 0.005 0.001 0.003 2-week 0.016 0.009 0.005 0.006 4-week 0.029 0.017 0.011 0.011 8-week 0.050 0.025 0.018 0.018

13-week 0.059 0.049 0.023 0.022 18-week 0.063 0.053 0.021 0.029 26-week 0.071 0.059 0.025 0.033

Aggregate E2-IA Expansions, % 1-week 0.016 0.014 0.009 0.008 2-week 0.016 0.016 0.011 0.009 4-week 0.023 0.020 0.015 0.011 8-week 0.024 0.025 0.019 0.013

13-week 0.028 0.029 0.023 0.020 18-week 0.028 0.032 0.024 0.021 26-week 0.031 0.033 0.026 0.025

385

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.4400.480

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

ID-SL 0%ID-SL 25%ID-SL 55%ID-SL 70%

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

WY-SL 0%WY-SL 25%WY-SL 55%WY-SL 70%

Figure 12.47: Effect of Granulated Slag on the Accelerated C 1293 Expansions of Aggregate A4-ID

Figure 12.48: Effect of Granulated Slag on the Accelerated C 1293 Expansions of Aggregate A2-WY

386

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

SD-SL 0%SD-SL 25%SD-SL 55%SD-SL 70%

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

IA-SL 0%IA-SL 25%IA-SL 55%IA-SL 70%

Figure 12.49: Effect of Granulated Slag on the Accelerated C 1293 Expansions of Aggregate C2-SD

Figure 12.50: Effect of Granulated Slag on the Accelerated C 1293 Expansions of Aggregate E2-IA

387

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.4400.480

A4-ID A2-WY C2-SD A2-IAAggregate Investigated

26-W

eek

(6-M

onth

) Exp

ansi

on, % 0% Slag

25% Slag55% Slag70% Slag

Observations related to these results are summarized in Table 12.23 where it can

be seen that replacing 25% of the weight of cement with granulated slag was not

effective in decreasing the 26-week expansions below 0.040% for any of A4-ID, A2-

WY, and C2-SD. A minimum of 55% granulated slag was needed to reduce the 26-

week expansions of all three aggregates below 0.040%. Aggregate E2-IA, which was

non-reactive in concrete made with cement only, exhibited innocuous expansions

also when 25, 55, and 70% granulated slag was used to replace the cement by

weight.

Figure 12.51: Comparison Between the 26-Week Expansions Generated Using the Accelerated C 1293 Procedures and the Different Granulated

Slag Replacement Levels

388

Table 12.23: Effect of Granulated Slag on ASR Using Accelerated C 1293

Aggregate ID

C 1293 One-Year Expansion

and Classification

Accelerated C 1293 13-Week Expansion and Classification

Granulated Slag Replacement by Weight of Cement

25% 55% 70%

A4-ID 0.379% Highly Reactive

0.396% Highly Reactive H.R. Innocuous Innocuous

A2-WY 0.107% Highly Reactive

0.083% Highly Reactive S.R. Innocuous Innocuous

C2-SD 0.053% Slowly Reactive

0.059% Slowly Reactive S.R. Innocuous Innocuous

E2-IA 0.025% Non-Reactive

0.028% Non-Reactive Innocuous Innocuous Innocuous

H.R. = Accelerated C 1293 26-week expansion > 0.070% S.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

Innocuous = Accelerated C 1293 26-week expansion < 0.040%

12.4.5 Effect of Calcined Clay Using Accelerated C 1293

The effect of calcined clay on the expansions caused by ASR was evaluated using

the accelerated C 1293 procedures. Two levels of cement replacement were

investigated, namely 17 and 25%. Four aggregates, identified in Table 12.1, were

used to prepare the different mixtures listed in Table 7.18 (these are the same

mixtures used for the standard C 1293). Results for these procedures are illustrated in

Table 12.24 and Figures 12.52 through 12.55. A comparison between the 26-week

expansions of the various replacement levels is shown in Figure 12.56. As mentioned

in Figure 12.1, a failure limit of 0.040% at 26 weeks was used to evaluate the use of

calcined clay.

389

Table 12.24: Accelerated C 1293 Expansions Using Calcined Clay

Time Calcined Clay Replacement Level by weight of Cement

0% 17% 25% Aggregate A4-ID Expansions, %

1-week 0.058 0.004 0.000 2-week 0.141 0.009 0.002 4-week 0.324 0.014 0.005 8-week 0.353 0.020 0.011 13-week 0.396 0.027 0.018 18-week 0.424 0.035 0.021 26-week 0.440 0.046 0.029

Aggregate A2-WY Expansions, % 1-week 0.027 0.001 0.000 2-week 0.038 0.004 0.003 4-week 0.062 0.010 0.006 8-week 0.077 0.017 0.010 13-week 0.083 0.029 0.013 18-week 0.088 0.036 0.019 26-week 0.096 0.049 0.025

Aggregate C2-SD Expansions, % 1-week 0.014 0.000 0.000 2-week 0.016 0.001 0.000 4-week 0.029 0.005 0.003 8-week 0.050 0.009 0.008 13-week 0.059 0.015 0.015 18-week 0.063 0.019 0.019 26-week 0.071 0.023 0.021

Aggregate E2-IA Expansions, % 1-week 0.016 0.014 0.005 2-week 0.016 0.015 0.008 4-week 0.023 0.019 0.010 8-week 0.024 0.023 0.014 13-week 0.028 0.026 0.019 18-week 0.028 0.027 0.021 26-week 0.031 0.029 0.022

390

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.4400.480

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

ID-CC 0%ID-CC 17%ID-CC 25%

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

WY-CC 0%WY-CC 17%WY-CC 25%

Figure 12.52: Effect of Calcined Clay on the Accelerated C 1293 Expansions of Aggregate A4-ID

Figure 12.53: Effect of Calcined Clay on the Accelerated C 1293 Expansions of Aggregate A2-WY

391

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

SD-CC 0%SD-CC 17%SD-CC 25%

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

26-W

eek

(6-M

onth

) Exp

ansi

on, %

IA-CC 0%IA-CC 17%IA-CC 25%

Figure 12.54: Effect of Calcined Clay on the Accelerated C 1293 Expansions of Aggregate C2-SD

Figure 12.55: Effect of Calcined Clay on the Accelerated C 1293 Expansions of Aggregate E2-IA

392

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.4400.480

A4-ID A2-WY C2-SD E2-IAAggregate Investigated

26-W

eek

(6-M

onth

) Exp

ansi

on, %

0% Calcined Clay17% Clacined Clay25% Calcined Clay

Observations related to these results are summarized in Table 12.25 where it can

be seen that replacing 17% of the weight of cement by calcined was effective in

decreasing the 26-week expansions below 0.040% for C2-SD but not A4-ID and A2-

WY. Twenty-five percent calcined clay was needed to reduce the 26-week

expansions of all aggregates below 0.040%. Aggregate E2-IA, which was non-

reactive in concrete made with cement only, exhibited innocuous expansions also

when 17 and 25% calcined clay was used to replace the cement by weight.

Figure 12.56: Comparison Between the 26-Week Expansions Generated Using the Accelerated C 1293 Procedures and the Different Calcined Clay

Replacement Levels

393

Table 12.25: Effect of Calcined Clay on ASR Using Accelerated C 1293

Aggregate ID

C 1293 One-Year Expansion

and Classification

Accelerated C 1293 13-Week Expansion and Classification

Calcined Clay Replacement by Weight of

Cement 17% 25%

A4-ID 0.379% Highly Reactive

0.396% Highly Reactive S.R. Innocuous

A2-WY 0.107% Highly Reactive

0.083% Highly Reactive S.R. Innocuous

C2-SD 0.053% Slowly Reactive

0.059% Slowly Reactive Innocuous Innocuous

E2-IA 0.025% Non-Reactive

0.028% Non-Reactive Innocuous Innocuous

H.R. = Accelerated C 1293 26-week expansion > 0.070% S.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

Innocuous = Accelerated C 1293 26-week expansion < 0.040%

12.4.6 Effect of Lithium Nitrate (LiNO3) Using Accelerated C 1293

The effect of LiNO3 on the expansions caused by ASR was evaluated using the

accelerated C 1293 procedures. The effects of three dosages were investigated:

1. 3.5 liters of LiNO3 per 1 kg of Na2O in the mixture (315 g of LiNO3 for concrete

mixtures)

2. 4.6 liters of LiNO3 per 1 kg of Na2O in the mixture (495 g of LiNO3 for concrete

mixtures)

3. 10.0 liters of LiNO3 per 1 kg of Na2O in the mixture (900 g of LiNO3 for

concrete mixtures)

A volume of the mixing water equal to 85% of the volume of LiNO3 added was

replaced by the LiNO3 solution according to the dosages mentioned. Four aggregates,

identified in Table 12.1, were used to prepare the different mixtures listed in Table

7.19 (these are the same mixture used for the standard C 1293). Results for these

procedures are illustrated in Table 12.26 and Figures 12.57 through 12.60. A

comparison between the 26-week expansions of the various replacement levels is

394

shown in Figure 12.61. As mentioned in Figure 12.1, a failure limit of 0.040% at 13

weeks is used to evaluate the use of lithium nitrate.

Table 12.26: Accelerated C 1293 Expansions Using Lithium Nitrate

Time Lithium Nitrate Weight

0g 315g 495g 900g Aggregate A4-ID Expansions, %

1-week 0.058 0.029 0.009 0.006 2-week 0.141 0.042 0.015 0.010 4-week 0.324 0.064 0.020 0.017 8-week 0.353 0.072 0.025 0.024

13-week 0.396 0.085 0.029 0.030 18-week 0.424 0.100 0.030 0.031 26-week 0.440 0.111 0.035 0.033

Aggregate A2-WY Expansions, % 1-week 0.027 0.007 0.004 0.002 2-week 0.038 0.012 0.009 0.006 4-week 0.062 0.022 0.013 0.011 8-week 0.077 0.030 0.019 0.015

13-week 0.083 0.042 0.025 0.020 18-week 0.088 0.049 0.026 0.021 26-week 0.096 0.058 0.028 0.025

Aggregate C2-SD Expansions, % 1-week 0.014 0.008 0.003 0.000 2-week 0.016 0.015 0.007 0.005 4-week 0.029 0.022 0.015 0.010 8-week 0.050 0.031 0.020 0.018

13-week 0.059 0.040 0.030 0.022 18-week 0.063 0.042 0.031 0.025 26-week 0.071 0.046 0.033 0.028

Aggregate E2-IA Expansions, % 1-week 0.016 0.011 0.009 0.001 2-week 0.016 0.016 0.016 0.006 4-week 0.023 0.019 0.018 0.012 8-week 0.024 0.022 0.021 0.018

13-week 0.028 0.028 0.026 0.023 18-week 0.028 0.031 0.028 0.026 26-week 0.031 0.033 0.030 0.029

395

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.440

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Time, Weeks

13-W

eek

(3-M

onth

) Exp

ansi

on, %

ID-LI 0gID-LI 315gID-LI 495gID-LI 900g

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Time, Weeks

13-W

eek

(3-M

onth

) Exp

ansi

on, %

WY-LI 0gWY-LI 315gWY-LI 495gWY-LI 900g

Figure 12.57: Effect of Lithium Nitrate on the Accelerated C 1293 Expansions of Aggregate A4-ID

Figure 12.58: Effect of Lithium Nitrate on the Accelerated C 1293 Expansions of Aggregate A2-WY

396

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Time, Weeks

13-W

eek

(3-M

onth

) Exp

ansi

on, %

SD-LI 0gSD-LI 315gSD-LI 495gSD-LI 900g

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Time, Weeks

13-W

eek

(3-M

onth

) Exp

ansi

on, %

IA-LI 0gIA-LI 315gIA-LI 495gIA-LI 900g

Figure 12.59: Effect of Lithium Nitrate on the Accelerated C 1293 Expansions of Aggregate C2-SD

Figure 12.60: Effect of Lithium Nitrate on the Accelerated C 1293 Expansions of Aggregate E2-IA

397

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.440

A4-ID A2-WY C2-SD A2-IAAggregate Investigated

13-W

eek

(3-M

onth

) Exp

ansi

on, % 0g Lithim Nitrate

315g Lithim Nitrate495g Lithim Nitrate900g Lithim Nitrate

Observations related to these results are summarized in Table 12.27 where it can

be seen that these results are identical to the ones generated using the standard C

1293 and summarized in Table 12.12. Using 315g of lithium nitrate (3.5 L) to replace

part of the mixing water was not effective in decreasing the 13-week expansions

below 0.040% for any of A4-ID, A2-WY, and C2-SD. All three aggregates required

a minimum of 495g (4.6 L) of LiNO3 in order to decrease the 13-week expansions of

concrete prisms below 0.040%. As can be seen in Figure 12.61, minimal benefit in

decreasing expansions was obtained by increasing the LiNO3 dosage from 495g (4.6

L) to 900g (10.0 L). Thus, for minimizing deleterious expansions due to ASR, a

minimum of 495g (4.6 L) of LiNO3 was required to replace part of the mixing water

(The replaced volume of water was equal to 85% of the volume of LiNO3 added).

Additional LiNO3 might not be very beneficial. Aggregate E2-IA, which was non-

Figure 12.61: Comparison Between the 26-Week Expansions Generated Using the Accelerated C 1293 Procedures and the Different Calcined Clay

Replacement Levels

398

reactive in concrete made without lithium nitrate, exhibited innocuous expansions

also when 315, 495, and 900g LiNO3 was used to replace a volume of the water.

Table 12.27: Effect of Lithium Nitrate on ASR Using Accelerated C 1293

Aggregate ID

C 1293 One-Year Expansion

and Classification

Accelerated C 1293 13-Week Expansion and Classification

LiNO3 Weight (Volume) Replacing Part of the Mixing

Water 315g

(3.5L) 495g

(4.6L) 900g

(10.0L)

A4-ID 0.379% Highly Reactive

0.396% Highly Reactive H.R. Innocuous Innocuous

A2-WY 0.107% Highly Reactive

0.083% Highly Reactive S.R. Innocuous Innocuous

C2-SD 0.053% Slowly Reactive

0.059% Slowly Reactive S.R. Innocuous Innocuous

E2-IA 0.025% Non-Reactive

0.028% Non-Reactive Innocuous Innocuous Innocuous

H.R. = Accelerated C 1293 13-week expansion > 0.070% S.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

Innocuous = Accelerated C 1293 13-week expansion < 0.040%

12.4.7 Effect of Air Entrainment Using Accelerated C 1293

In order to investigate the effect of air entrainment on the expansions due to ASR

using the accelerated C 1293, two ranges of entrained air were investigated, namely

between 2 and 4% and between 6 and 8%. Entrained air refers to total air content

reduced by the entrapped air content. The four aggregates, mentioned Table 12.1,

were used to prepare the different mixtures listed in Table 7.13. Results for these

procedures are illustrated in Table 12.28 and Figures 12.62 through 11.65. A

comparison between the 13-week expansions of the different air levels is shown in

Figure 12.66. As mentioned in Figure 12.1, a failure limit of 0.040% at 13 weeks was

used to evaluate the use of air entrainment.

399

Table 12.28: Accelerated C 1293 Expansions Using Air Entrainment

Time Entrained Air Content Range

0% 2 – 4% 6 - 8% Aggregate A4-ID Expansions, %

1-week 0.058 0.061 0.098 2-week 0.141 0.109 0.152 4-week 0.324 0.225 0.256 8-week 0.353 0.433 0.341 13-week 0.396 0.500 0.389 18-week 0.424 0.522 0.457 26-week 0.440 0.541 0.475

Aggregate A2-WY Expansions, % 1-week 0.027 0.015 0.038 2-week 0.038 0.029 0.052 4-week 0.062 0.048 0.078 8-week 0.077 0.060 0.090 13-week 0.083 0.079 0.101 18-week 0.088 0.082 0.118 26-week 0.096 0.091 0.210

Aggregate C2-SD Expansions, % 1-week 0.014 0.015 0.013 2-week 0.016 0.019 0.020 4-week 0.029 0.031 0.029 8-week 0.050 0.049 0.041 13-week 0.059 0.058 0.050 18-week 0.063 0.066 0.059 26-week 0.071 0.075 0.063

Aggregate E2-IA Expansions, % 1-week 0.016 0.015 0.014 2-week 0.016 0.016 0.017 4-week 0.023 0.022 0.020 8-week 0.024 0.024 0.022 13-week 0.028 0.030 0.025 18-week 0.028 0.033 0.029 26-week 0.031 0.035 0.031

400

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Time, Weeks

13-W

eek

(3-M

onth

) Exp

ansi

on, %

ID-AE 0%ID-AE 2-4%ID-AE 6-8%

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Time, Weeks

13-W

eek

(3-M

onth

) Exp

ansi

on, %

WY-AE 0%WY-AE 2-4%WY-AE 6-8%

Figure 12.62: Effect of Air Entrainment on the Accelerated C 1293 Expansions of Aggregate A4-ID

Figure 12.63: Effect of Air Entrainment on the Accelerated C 1293 Expansions of Aggregate A2-WY

401

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Time, Weeks

13-W

eek

(3-M

onth

) Exp

ansi

on, %

SD-AE 0%SD-AE 2-4%SD-AE 6-8%

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Time, Weeks

13-W

eek

(3-M

onth

) Exp

ansi

on, %

IA-AE 0%IA-AE 4%IA-AE 6%

Figure 12.64: Effect of Air Entrainment on the Accelerated C 1293 Expansions of Aggregate C2-SD

Figure 12.65: Effect of Air Entrainment on the Accelerated C 1293 Expansions of Aggregate E2-IA

402

0.000

0.100

0.200

0.300

0.400

0.500

0.600

A4-ID A2-WY C2-SD A2-IAAggregate Investigated

13-W

eek

(3-m

onth

) Exp

ansi

on, %

0% Air2-4% Air6-8% Air

Observations related to these results are summarized in Table 12.25 where it can

be seen that using air entrainment was not effective in decreasing the 13-week

expansions to safe level for any of the reactive aggregates. It is worth noting that

these results are similar to the ones generated using the standard C 1293 and

summarized in Table 12.14. It is clear from Figure 12.66 that ranges of air

entrainment investigated did not result in any decrease in the 13-week expansions of

any of the reactive aggregates investigated. In the case of A4-ID, 2 to 4% entrained

air caused a drastic increase in the 13-week expansion and in the case of A2-WY, 6

to 8% entrained air also caused an increase in the 13-week expansion. Thus, it was

concluded that air entrainment is not effective in mitigating the alkali-silica reactivity

of aggregates in portland cement concrete.

Figure 12.66: Comparison Between the 13-Week Expansions Generated Using the Accelerated C 1293 Procedures and the Different Air

Entrainment Contents

403

Table 12.29: Effect of Air Entrainment on ASR Using Accelerated C 1293

Aggregate ID

C 1293 One-Year Expansion

and Classification

Accelerated C 1293 13-Week Expansion and Classification

Entrained Air Content Range

2 - 4% 6- 8%

A4-ID 0.379% Highly Reactive

0.396% Highly Reactive H.R. H.R.

A2-WY 0.107% Highly Reactive

0.083% Highly Reactive H.R. H.R.

C2-SD 0.053% Slowly Reactive

0.059% Slowly Reactive S.R. S.R.

E2-IA 0.025% Non-Reactive

0.028% Non-Reactive Innocuous Innocuous

H.R. = Accelerated C 1293 13-week expansion > 0.070% S.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

Innocuous = Accelerated C 1293 13-week expansion < 0.040%

12.4.8 Effect of Lowering the Cement Alkali Content Using Accelerated C 1293

In order to evaluate the effect of lowering the cement alkali content on ASR, the

accelerated C 1293 (at 600C) procedures were performed using cement Na2Oequiv.

contents of 1.25% (required by C 1293), 0.90%, and 0.60% Na2Oequiv.. The Na2Oequiv.

contents were achieved by using a cement with a total alkali content of 0.60% and

adding necessary amounts of NaOH to the mixing water. The highly reactive

aggregate, A6-NM, was added for this investigation in order to obtain more

confidence in the effects of Na2Oequiv. on the ASR expansions caused by such

aggregates. Mixture proportions, which were identical to the ones used for the C

1293 and accelerated C 1293 procedures, are listed in Table 7.12. Expansion results

are listed in Table 12.30 and Figures 12.67 through 12.70. An expansion limit of

0.040% at 13 weeks was used to differentiate between reactive and innocuous

expansions. A comparison between the 13-week expansions of concrete prisms made

with the different cement alkali contents is shown in Figure 12.71.

404

Table 12.30: Accelerated C 1293 Expansions Using Different Cement Na2Oequiv. Contents

Time Cement Na2Oequiv. Content

1.25% 0.90% 0.60% Aggregate A6-NM Expansions, %

1-week 0.057 0.037 0.019 2-week 0.208 0.041 0.024 4-week 0.352 0.044 0.027 8-week 0.372 0.054 0.040 13-week 0.407 0.099 0.052

Aggregate A4-ID Expansions, % 1-week 0.058 0.043 0.025 2-week 0.141 0.046 0.024 4-week 0.324 0.045 0.024 8-week 0.353 0.064 0.040 13-week 0.396 0.084 0.052

Aggregate A2-WY Expansions, % 1-week 0.027 0.019 0.019 2-week 0.038 0.019 0.020 4-week 0.062 0.023 0.023 8-week 0.077 0.032 0.026 13-week 0.083 0.046 0.033

Aggregate C2-SD Expansions, % 1-week 0.014 0.014 0.012 2-week 0.016 0.020 0.014 4-week 0.029 0.024 0.015 8-week 0.050 0.028 0.013 13-week 0.059 0.029 0.014

405

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

0 2 4 6 8 10 12 14

Time, Weeks

13-W

eek

Exp

ansi

on, %

NM-1.25% Na2ONM-0.90% Na2ONM-0.60% Na2O

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

0 2 4 6 8 10 12 14

Time, Weeks

13-W

eek

Exp

ansi

on, %

ID-1.25% Na2OID-0.90% Na2OID-0.60% Na2O

Figure 12.67: Effect of Different Cement Alkali Contents on the Accelerated C 1293 Expansions of Aggregate A6-NM

Figure 12.68: Effect of Different Cement Alkali Contents on the Accelerated C 1293 Expansions of Aggregate A4-ID

406

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0 2 4 6 8 10 12 14

Time, Weeks

13-W

eek

Exp

ansi

on, %

WY-1.25% Na2OWY-0.90% Na2OWY-0.60% Na2O

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0 2 4 6 8 10 12 14

Time, Weeks

13-W

eek

Exp

ansi

on, %

SD-1.25% Na2OSD-0.90% Na2OSD-0.60% Na2O

Figure 12.69: Effect of Different Cement Alkali Contents on the Accelerated C 1293 Expansions of Aggregate A2-WY

Figure 12.70: Effect of Different Cement Alkali Contents on the Accelerated C 1293 Expansions of Aggregate C2-SD

407

0.0000.0400.0800.1200.1600.2000.2400.2800.3200.3600.4000.440

A6-NM A4-ID A2-WY C2-SD

Aggregate Investigated

13-W

eek

Exp

ansi

on, % 1.25% Na2O

0.90% Na2O0.60% Na2O

Observations related to these results are summarized in Table 12.31 where it can

be seen that at 1.25 Na2Oequiv., the alkali level required by the C 1293 procedures, all

aggregates investigated were reactive. At 0.90% Na2Oequiv., only the slowly reactive

aggregate, C2-SD, exhibited innocuous expansions. At 0.60% the slowly reactive

aggregate, C2-SD, and the moderately reactive aggregate, A2-WY, exhibited

innocuous expansions. At all three levels, the highly reactive aggregates, A6-NM and

A4-ID, showed reactive expansions. From Figures 12.67 through 12.71, it can be

noted that as the Na2Oequiv. content decreased the expansion decreased with the

biggest decrease noted for the highly reactive aggregates, A6-NM and A4-ID. Even

though these two aggregates exhibited reactive expansion at 0.60% Na2Oequiv., their

13-week expansions were drastically decreased. Thus, using a cement alkali content

as low as 0.60% resulted in the slowly and moderately reactive aggregate to be

innocuous; however, the highly reactive aggregates were still showing reactive

expansions.

Figure 12.71: Comparison Between the 13-Week Accelerated C 1293 Expansions of Concrete Prisms Made with Different Na2Oequiv. Contents

408

Table 12.31: Effect of Na2Oequiv. Content on ASR Using Accelerated C 1293

Aggregate ID

C 1293 One-Year Expansion

and Classification

Accelerated C 1293 13-Week Expansion and Classification

Na2Oequiv. Cement Content

1.25% 0.90% 0.60%

A6-NM 0.411% Highly Reactive

0.407% Highly Reactive H.R. H.R. S.R.

A4-ID 0.379% Highly Reactive

0.396% Highly Reactive H.R. H.R. S.R.

A2-WY 0.107% Highly Reactive

0.083% Highly Reactive H.R. S.R. Innocuous

C2-SD 0.053% Slowly Reactive

0.059% Slowly Reactive S.R. Innocuous Innocuous

H.R. = Accelerated C 1293 13-week expansion > 0.070% S.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

Innocuous = Accelerated C 1293 13-week expansion < 0.040%

12.4.9 Comparison Between the Effectiveness of the Different Mitigation

Alternatives

With the exception of air entrainment, expansions caused by ASR decreased as

the mitigating alternative dosage increased in the mixture. This was true for the

reactive aggregates A4-ID, A2-WY, and C 2-SD combined with Class C fly ash,

Class F fly ash, silica fume, granulated slag, calcined clay, and lithium nitrate. Even

though not all the dosages decreased the expansions to safe level, they did cause a

decrease in the expansions. Lowering the total alkali content of the cement resulted

in decreasing the expansions of investigated aggregates. A comparison between the

effectiveness of the different dosages investigated for all four aggregates is illustrated

in Figures 12.72 through 12.75.

409

Highly Reactive Aggregate A4-ID

0.000 0.070 0.140 0.210 0.280 0.350 0.420 0.490

No Mitigation25% Slag

20% Class C Fly Ash315g LiNO3

5% Silica Fume15% Class F Fly Ash

27.5% Class C Fly Ash25% Class F Fly Ash

10% Silica Fume35% Class C Fly Ash

17% Calcined Clay495g LiNO3900g LiNO3

55% Slag70%Slag

25% Calcined ClayM

itiga

tion

Alte

rnat

ive

26-Week Expansion, %

Best

Worst

Highly Reactive Aggregate A2-WY

0.000 0.040 0.080 0.120

No Mitigation20% Class C Fly Ash

27.5% Class C Fly Ash25% Slag

15% Class F Fly Ash35% Class C Fly Ash

5% Silica Fume315g LiNO3

17% Calcined Clay10% Silica Fume

70%Slag495g LiNO3

25% Class F Fly Ash55% Slag

25% Calcined Clay900g LiNO3

Miti

gatio

n A

ltern

ativ

e

26-Week Expansion, %

Best

Worst

Figure 12.72: Comparison Between the Different Mitigation Alternatives Used With Aggregate A4-ID and the Accelerated C 1293

Figure 12.73: Comparison Between the Different Mitigation Alternatives Used With Aggregate A2-WY and the Accelerated C 1293

410

Slowly Reactive Aggregate C2-SD

0.000 0.010 0.020 0.030 0.040 0.050 0.060 0.070 0.080

No Mitigation20% Class C Fly Ash

25% Slag15% Class F Fly Ash

5% Silica Fume27.5% Class C Fly

315g LiNO3495g LiNO3

70%Slag10% Silica Fume

35% Class C Fly Ash900g LiNO3

55% Slag17% Calcined Clay

25% Class F Fly Ash25% Calcined Clay

Miti

gatio

n A

ltern

ativ

e

26-Week Expansion, %

Best

Worst

Innocuous Aggregate E2-IA

0.000 0.010 0.020 0.030 0.040

5% Silica Fume25% Slag

315g LiNO320% Class C Fly Ash

No Mitigation15% Class F Fly Ash

27.5% Class C Fly Ash495g LiNO3

10% Silica Fume35% Class C Fly Ash

17% Calcined Clay25% Class F Fly Ash

900g LiNO355% Slag70%Slag

25% Calcined Clay

Miti

gatio

n A

ltern

ativ

e

26-Week Expansion, %

Best

Worst

Figure 12.74: Comparison Between the Different Mitigation Alternatives Used With Aggregate C2-SD and the Accelerated C 1293

Figure 12.75: Comparison Between the Different Mitigation Alternatives Used With Aggregate E2-IA and the Accelerated C 1293

411

12.4.10 Summary of the Evaluation of the mitigation Alternative Using the

Accelerated Concrete Prism Test

The accelerated C 1293, performed at 600C, was used to evaluate the effectiveness

of the mitigation alternatives using a 13-week expansion limit of 0.040% for lithium

nitrate, air entrainment, and low Na2Oequiv. content, and a 26-week expansion limit of

0.040% for Class C fly ash, Class F fly ash, silica fume, granulated slag, and calcined

clay. Table 12.32 includes a summary of this evaluation. As can be seen from this

table, the only alternatives that were effective with all aggregates investigated are the

use of a minimum of 55% granulated slag and a minimum of 25% calcined clay.

Alternatives that were effective with the slowly reactive aggregates C2-SD are the

use of a minimum of 35% Class C fly ash, 15% Class F fly ash, 10% silica fume,

55% slag, 17% calcined clay by weight of cement, the use of a minimum of 495g of

LiNO3 (4.6L per 1 kg of Na2Oeqiv.), and the use of cement with a maximum Na2Oequiv.

content of 0.90%. Alternatives that were effective with the moderately reactive

aggregate A2-WY are the use of a minimum of 25% Class F fly ash, 55% slag, 25%

calcined clay by weight of cement, the use of a minimum of 495g of LiNO3 (4.6L per

1 kg of Na2Oeqiv.), and the use of cement with a maximum Na2Oequiv. content of

0.60%. Alternatives that were effective with the highly reactive aggregate A4-ID are

the use of a minimum of 55% slag and 25% calcined clay by weight of cement, and

the use of a minimum of 495g of LiNO3 (4.6L per 1 kg of Na2Oeqiv.). It seems that

different levels of aggregate reactivity required different mitigation alternatives. It

should be noted that aggregate E2-IA, which was classified innocuous when tested

according to C 1293, exhibited innocuous expansions when tested using all the

mitigation alternatives.

412

Table 12.32: Effectiveness of the Mitigation Alternatives Using the Accelerated C 1293 Criteria

Cementitious Material

Replacement Level By Weight of Cement

Aggregate ID, 13-Week Expansion, C 1293 Reactivity Classification

A4-ID 0.396% Highly

Reactive

A2-WY 0.083% Highly

Reactive

C2-SD 0.059% Slowly

Reactive

E2-IA 0.028%

Innocuous

Class C Fly Asha

20% H.R. H.R. S.R. Innocuous

27.5% H.R. H.R. S.R. Innocuous

35% S.R. S.R. Innocuous Innocuous

Class F Fly Asha

15% H.R. S.R. S.R. Innocuous

25% S.R. Innocuous Innocuous Innocuous

Silica Fumea

5% H.R. H.R. S.R. Innocuous

10% S.R. S.R. Innocuous Innocuous

Granulated Slaga

25% H.R. S.R. S.R. Innocuous

55% Innocuous Innocuous Innocuous Innocuous

70% Innocuous Innocuous Innocuous Innocuous

Calcined Claya

17% S.R. S.R. Innocuous Innocuous

25% Innocuous Innocuous Innocuous Innocuous

Chemical Material Dosage

Aggregate ID, 13-Week Expansion, C 1293 Reactivity Classification

A4-ID 0.396% Highly

Reactive

A2-WY 0.083% Highly

Reactive

C2-SD 0.059% Slowly

Reactive

E2-IA 0.028%

Innocuous

Lithium Nitrateb 315 g H.R. S.R. S.R. Innocuous

495 g Innocuous Innocuous Innocuous Innocuous

900 g Innocuous Innocuous Innocuous Innocuous

Entrained Airb 2 - 4% H.R. H.R. S.R. Innocuous

6 - 8% H.R. H.R. S.R. Innocuous

413

Table 12.32 (Cont’d): Effectiveness of the Mitigation Alternatives Using the Accelerated C 1293 Criteria

Cementitious Material

Na2Oequiv. Content

A6-NM 0.407% Highly

Reactive

A4-ID 0.396% Highly

Reactive

A2-WY 0.083% Highly

Reactive

C2-SD 0.059% Slowly

Reactive

Cementb 0.90% H.R. H.R. S.R. Innocuous

0.60% S.R. S.R. Innocuous InnocuousaH.R. = Accelerated C 1293 26-week expansion > 0.070% aS.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

aInnocuous = Accelerated C 1293 26-week expansion < 0.040%

bH.R. = Accelerated C 1293 13-week expansion > 0.070% bS.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

bInnocuous = Accelerated C 1293 13-week expansion < 0.040%

12.5 INVESTIGATION OF MITIGATION ALTERNATIVES USING

ACCELERATED C 1293 RESULTS AND CEMENTS WITH

DIFFERENT Na2Oequiv. CONTENTS

Earlier sections of this chapter were devoted to investigating the effects of the

mitigation alternatives using the procedures of C 1293 (at 380C) or the accelerated C

1293 (at 600C) both of which call for increasing the cement alkali content to 1.25%

Na2Oequiv.. It was found that few alternatives were able to decrease the expansions of

highly reactive aggregates to safe levels. An attempt was made to evaluate the

effectiveness of these alternatives in decreasing the expansions of the highly reactive

aggregate, A6-NM, using cement with an alkali content of 0.80% Na2Oequiv.. The

purpose of this investigation was as follows:

1. Evaluate the effect of coupling the use of a mitigation alternative with a low

alkali cement on the reactivity of highly reactive aggregates and

2. Confirm the conclusions obtained using ASTM C 1260 (the mortar bar test).

According to the C 1260 results (Chapter 11, Table 11.30), at a cement alkali

content lower than 0.80% Na2Oequiv., effective alternatives include the use of a

414

minimum of 17% calcined clay, 50% granulated slag, 20% Class F fly ash, 10%

silica fume, 35% Class C fly ash, and 3.5 L LiNO3 per 1 kg of Na2Oequiv..

The accelerated C 1293 procedures were used to evaluate the effectiveness of the

mitigation alternative on the ASR expansions of aggregate A6-NM using a cement

with a total alkali content of 0.80%. Expansion limits were as specified earlier.

Expansion results for these procedures are listed in Table 12.33 and Figures 12.76

through 12.78.

Table 12.33: Accelerated C 1293 Expansions of Aggregate A6-NM Using Different Mitigation Alternatives and 0.80% Na2Oequiv. Content Cement

Mitigation Alternative

Replacement Level by

Weight of Cement

Accelerated C 1293 Expansion For Aggregate A6-NM %

1-week 2-week 4-week 8-week 13-week 18-week 26-weekClass C Fly Ash

25% 0.002 0.009 0.015 0.021 0.036 0.049 0.063 35% 0.001 0.005 0.010 0.015 0.021 0.028 0.032

Class F Fly Ash

15% 0.006 0.011 0.019 0.024 0.033 0.049 0.056 20% 0.000 0.005 0.011 0.020 0.024 0.029 0.031

Silica Fume

5% 0.009 0.019 0.026 0.037 0.049 0.060 0.082 10% 0.001 0.006 0.010 0.015 0.020 0.029 0.034

Granulated Slag

25% 0.050 0.098 0.121 0.185 0.200 0.210 0.231 50% 0.001 0.003 0.008 0.015 0.020 0.027 0.031

Calcined Clay

17% 0.000 0.002 0.005 0.010 0.019 0.021 0.030 25% 0.000 0.001 0.004 0.010 0.017 0.020 0.025

Lithium Nitrate

315g 0.001 0.008 0.015 0.021 0.028 0.033 0.044 495g 0.000 0.002 0.009 0.018 0.022 0.025 0.029

Entrained Air

2-4% 0.070 0.119 0.153 0.185 0.201 0.220 0.231 6-8% 0.050 0.099 0.120 0.168 0.194 0.210 0.219

415

0.000

0.050

0.100

0.150

0.200

0.250

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

Exp

ansi

on, %

NM-SF 5%NM-SF 10%NM-SL 25%NM-SL 50%NM-CC 17%NM-CC 25%

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0 2 4 6 8 101214161820 22242628

Time, Weeks

Exp

ansi

on, % NM-FAC 25%

NM-FAC 35%NM-FAF 15%NM-FAF 20%

Figure 12.76: Effect of Silica Fume, Granulated Slag, and Calcined Clay on the Accelerated C 1293 Expansions of Aggregate A6-NM Using a 0.80%

Na2Oequiv. Cement

Figure 12.77: Effect of Class C Fly Ash and Class F Fly Ash on the Accelerated C 1293 Expansions of Aggregate A6-NM Using a 0.80%

Na2Oequiv. Cement

416

0.000

0.050

0.100

0.150

0.200

0.250

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Time, Weeks

Exp

ansi

on, % NM-LI 315 g

NM-LI 495 gNM-AE 4%NM-AE 6%

Findings from these results are summarized in Table 12.34 where it can be seen

that using a maximum of 0.80% Na2Oequiv. cement with the highly reactive aggregate

A6-NM allowed the use of more alternatives for mitigating excessive ASR

expansions. Alternatives that resulted in innocuous expansions for aggregate A6-NM

and 0.80% Na2Oequiv. cement included the use of a minimum of a 35% Class C fly

ash, 20% Class F fly ash, 10% silica fume, 50% granulated slag, 17% calcined clay,

and 495g of LiNO3 (4.6L of LiNO3 per 1 kg of Na2Oequiv. in mixture). These results

are comparable to the ones obtained using ASTM C 1260 (the two weeks mortar bar

test). Thus, using a 0.80% Na2Oequiv. cement allowed more flexibility with

alternatives and resulted in more efficient mitigation of the alkali-silica reactivity of

the highly reactive aggregate A6-NM.

Figure 12.78: Effect of Lithium Nitrate and Air Entrainment on the Accelerated C 1293 Expansions of Aggregate A6-NM Using a 0.80%

Na2Oequiv. Cement

417

Table 12.34: Effectiveness of Different Mitigation Alternatives Using The Accelerated C 1293 with Aggregate A6-NM and 0.80% Na2Oequiv. Cement

Mitigation Alternative

Replacement Level by

Weight of Cement

Aggregate A6-NM 13-Week C 1293 (600C) Expansion of

0.407% Highly Reactive

Class C Fly Asha

25% S.R. 35% Innocuous

Class F Fly Asha

15% S.R. 20% Innocuous

Silica Fumea

5% H.R. 10% Innocuous

Granulated Slaga

25% H.R. 50% Innocuous

Calcined Claya

17% Innocuous 25% Innocuous

Lithium Nitrateb

315g S.R. 495g Innocuous

Entrained Airb

2-4% H.R. 6-8% H.R.

aH.R. = Accelerated C 1293 26-week expansion > 0.070% aS.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

aInnocuous = Accelerated C 1293 26-week expansion < 0.040%

bH.R. = Accelerated C 1293 13-week expansion > 0.070% bS.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

bInnocuous = Accelerated C 1293 13-week expansion < 0.040%

418

12.6 SUMMARY AND SPECIFICATIONS

Tables 12.35 and 12.36 list alternatives that were effective in mitigating the alkali

silica reactivity of aggregates investigated. These results were generated using the

accelerated C 1293 procedures performed at 600C.

Table 12.35: Effective ASR Mitigation Alternatives When Evaluating Aggregates Using Accelerated C 1293 at 600C

Cementitious Material

Aggregate ID, 13-Week Accelerated C 1293 Expansion, Classification A4-ID

0.396% Highly Reactive

A2-WY 0.083%

Highly Reactive

C2-SD 0.059%

Slowly Reactive

E2-IA 0.028%

Innocuous Minimum Replacement Level by Weight of Cement

Calcined Clay 25% 25% 17% 0%

Granulated Slag 55% 55% 55% 0%

Class F Fly Ash > 25% 25% 25% 0%

Silica Fume 10% 0%

Class C Fly Ash > 35% > 35% 35% 0%

Cement Minimum Cement Na2Oequiv. Content

0.60% 0.90% Not Applicable

Chemical Admixture Minimum LiNO3 Volume (weight) per 1 kg of Na2Oequiv.

Lithium Nitrate 4.6 L (495 kg) 4.6 L (495 kg) 4.6 L (495 kg) 0g

Shaded Areas = Alternative could not be used

419

Table 12.36: Effective ASR Mitigation Alternatives for Highly Reactive Aggregate A6-NM (Accelerated C 1293 13-week of 0.407%) Evaluated Using

Accelerated C 1293 (600C) with 0.80% Na2Oequiv. Cement

Cementitious Material Minimum Replacement Levels by Weight of Cement

Calcined Clay 17%

Granulated Slag 50%

Class F Fly Ash 25%

Silica Fume 10%

Class C Fly Ash 35%

Chemical Material Minimum LiNO3 Volume (Weight) per 1 kg of Na2Oequiv.

Lithium Nitrate 4.6 L (495 kg)

Air Entrainment

Shaded Areas = Alternative could not be used

420

CHAPTER THIRTEEN

COMPARISON BETWEEN C 1260, C 1293, PETROGRAPHIC ANALYSIS, AND FIELD INVESTIGATION RESULTS

13.1 INTRODUCTION

This chapter includes a comparison between the results generated using the C

1260 (mortar-bar test) and the C 1293 (concrete-prism test) testing procedures. The

first part of this chapter is dedicated to comparing testing results for assessing the

potential reactivity of aggregates. The second part is concerned with comparing the

results of evaluating mitigation alternatives using both testing procedures.

Discussions and conclusions are stated when appropriate.

13.2 ASTM C 1260, ASTM C 1293, PETROGRAPHIC EXAMINATION, AND

FIELD PERFORMANCE

Comparing the results of C 1260 and C 1293 consisted of comparing the 14-day

expansions generated using C 1260 versus the 52-week expansions generated using

C 1293. A list of these expansions is included in Table 13.1 and a comparison is

shown in Figure 13.1. The following observations were noted:

1. Aggregates with 14-day expansions below 0.10% correlated well with 52-week

expansions below 0.040%. These aggregates had good field performance and no

reactive materials were found after a petrographic examination. Thus, innocuous

aggregates were correctly identified using C 1260 and C 1293.

2. Aggregates with 14-day expansions between 0.10% and 0.20% correlated well

with 52-week expansions between 0.040% and 0.070%. Slowly reactive

aggregates showing 14-day expansions between 0.10% and 0.20% were also

identified as slowly reactive using C 1293 with 52-week expansions between

0.040% and 0.070%. This correlated well with the field performance of these

aggregates. However, a petrographic analysis failed to detect the reactive

materials in these aggregates. Thus, for slowly reactive aggregates, C 1260 and C

421

1293 correlated well with field performance but petrographic examination was

not effective.

Table 13.1: C 1260 14-Day Expansions and C 1293 52-Week Expansions

Aggregate ID

Petrographic Analysisa

Reported Field

Performance

C 1260 14-Day

%

C 1293 52-Weeks

%

A1-WY Reactive Materials Reactive 0.24

H.R 0.073 H.R.

A2-WY Reactive Materials Reactive 0.29

H.R. 0.107 H.R.

A4-ID Reactive Materials Reactive 0.79

H.R. 0.305 H.R.

A6-NM Reactive Materials Reactive 0.91

H.R. 0.308 H.R.

A7-NC Reactive Materials Reactive 0.31

H.R. 0.085 H.R.

A9-NE Reactive Materials Reactive 0.28

H.R. 0.051 S.R.

A10-PA Reactive Materials Reactive 0.26

H.R. 0.043 S.R.

B2-MD No Reactive Materials Reactive 0.12

S.R. 0.046 S.R.

B4-VA No Reactive Materials No Record 0.15

S.R. 0.041 S.R.

C2-SD No Reactive Materials Reactive 0.17

S.R. 0.053 S.R.

D2-IL No Reactive Materials

Good with high alkali cement

0.02 Innocuous

0.022 Innocuous

E4-NV Reactive Materials

Good with mitigation

0.25 H.R.

0.060 S.R.

E6-IN No Reactive Materials

Good with High alkali cement

0.25 H.R.

0.022 Innocuous

E2-IA No Reactive Materials

Good with High alkali cement

0.42 H.R.

0.025 Innocuous

E8-NM Reactive Materials

Good with mitigation

0.36 H.R.

0.064 S.R.

H.R. = Highly Reactive; S.R. = Slowly Reactive Shaded areas are instances where C 1260 over estimated the reactivity as compared to ASTM C 1293

a Petrographic analysis obtained through reported provided by aggregate producers and confirmed by a petrographer, Mr. Tom Patti (Appendix D).

422

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0.32

0.36

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

14-Day C 1260 Expansions, %

52-W

eek

C 1

293

Exp

ansi

ons,

%

E2-IAE6-IN

C 1260 Failure Criteria

C 1293 Failure Criteria

Figure 13.1: C 1260 Results vs. C 1293 Results Note on Figure 13.1: C 1293 one-year expansions plotted on the y-axis and C 1260 14-day expansions plotted on the x-axis. The Figure shows how the C 1260 expansions are overestimating the reactivity of aggregates. Aggregates classified as slowly reactive using C 1293 are shown as highly reactive by the C 1260 criteria. In addition, E6-IN and E2-IA that are innocuous by C 1293 are found highly reactive with C 1260.

423

3. Fourteen-day expansions higher than 0.20% correlated well with 52-week

expansions higher than 0.070%. Moderately and rapidly reactive aggregates were

correctly identified using both C 1260 (0.20% limit) and C 1293 (0.070% limit).

These aggregates were reactive in field applications and contained reactive

materials when examined petrographically.

4. Potentially reactive aggregates showed 14-day expansions higher than 0.10% (C

1260) and 52-week expansions (C 1293) higher than 0.040%.

5. A9-NE did not satisfy the above observations. A9-NE is a mixture of coarse and

fine aggregate that has shown a 14-day expansion of 0.280% and a 52-week

expansion of 0.051%. Thus, using C 1260, the aggregate was classified as rapidly

reactive but using C 1293 it was classified as slowly reactive. This behavior was

expected since for C 1293 the aggregate was used “as is” including the fine and

coarse portions. The coarse portion of the aggregate consisted of an innocuous

limestone which when combined with the fine portion will result in an aggregate

with lower reactivity than the fine portion. The C 1260 procedures call for

separating the aggregate into several sieve sizes and using a percentage of each

sieve. As a result, only the fine portion of the mixed aggregate was tested with C

1260, which explains why the C 1260 reactivity was higher than the C 1293

reactivity. Thus, C 1260 cannot be accurately used to predict the reactivity of

mixed aggregates. This should be accomplished using C 1293.

6. E2-IA and E6-IN also presented discrepancies from the above observations as

seen in Figure 13.1. Both aggregates were reported as potentially reactive when

tested using C 1260 (0.42% and 0.25% respectively) but both passed C 1293

(0.025% and 0.022% respectively). As noted in Table 13.1, these two aggregates

have been successfully used in field applications with high alkali cements (at

least as high as 0.9%). In addition, petrographic analysis indicated that the two

aggregates do not contain reactive materials. The C 1293 results correlated best

with the field performance and the petrographic analysis results and was

424

considered to be more realistic. It was mentioned earlier that this problem was

also noted by the NAA results where they had 10 aggregates that passed C 1293

but failed C 1260. Thus, it can be concluded that the C 1260 procedures are too

severe for some aggregates that pass C 1293.

7. ASTM C 1260 was also too severe for A10-PA, E4-NV, and E8-NM resulting in

an over estimation of the aggregates’ reactivity. A10-PA, E4-NV, and E8-NM

exhibited 14-day expansions of 0.26, 0.25, and 0.36%, respectively, indicating

that the aggregates should be characterized as highly reactive. However, these

aggregates exhibited one-year expansions of 0.043, 0.060, and 0.064%,

respectively, indicating that the aggregates should be characterized as slowly

reactive. Thus, C 1260 resulted in a more conservative estimate of the reactivity.

Nevertheless, both tests indicated that the three aggregates were reactive, which

corresponds to the field performance and petrographic analysis record.

8. From the above comments, it can be concluded that C 1260 should be used only

as a screening method in combination with C 1293. C 1260 should not be solely

used to determine the potential reactivity of aggregates but should be supported

by C 1293. On the other hand, C 1293 could be solely used to predict the

potential reactivity of aggregates.

9. Petrographic analysis failed to detect the reactive materials present in the slowly

reactive aggregates investigated (detailed reports in Appendix D). Petrography

should not be used with this type of aggregates.

10. A summary of an appropriate test combination for determining the potential

alkali-silica reactivity of aggregate is shown in Figure 13.2.

425

Potential Alkali-Silica Reactivity Characterization of Aggregates

ASTM C 1260 Mortar-Bar Test

Results required within 2 weeks No Time Constraint

14-day expansion > 0.20%

Innocuous Yes

No

0.10% < 14-day

expansion < 0.20%

Slowly Reactive

Yes

14-day expansion < 0.10%

Highly Reactive

Yes

No

ASTM C 1293 Concrete Prism Test

380C 600C

If ti

me

is a

vaila

ble

verif

y us

ing

AST

M C

129

3 Innocuous

One-year expansion < 0.040%

13-week expansion < 0.040%

Yes

No No

Slowly Reactive

0.040% < one-year

expansion < 0.070%

0.040% < 13-week

expansion < 0.070%

Yes

No No

Highly Reactive

One-year expansion > 0.070%

13-Week Expansion > 0.070%

Yes

Figure 13.2a: Characterization of Aggregate Potential Alkali-Silica Reactivity

426

Figure 13.2b: Summary Characterization of Aggregate Potential Alkali-Silica Reactivity

Potential Alkali-Silica Reactivity Characterization of Aggregates

ASTM C 1260 Mortar-Bar Test

Signs of Reactivity?

ASTM C 1293 Concrete-Prism Test

Signs of Reactivity?

Potentially Reactive Aggregate Special Requirements

Innocuous Aggregate No Special Requirement

If time available

Yes No

Yes

Yes No

427

13.3 C 1260 MITIGATION ALTERNATIVES vs. C 1293 MITIGATION

ALTERNATIVES

This comparison consisted of evaluating mitigation alternatives using both C 1260

and C 1293. Expansion limits used to evaluate the alternatives using both testing

procedures are listed in Table 13.2.

Table 13.2: Expansion Limits Used to Evaluate Effectiveness of Mitigation Alternatives

Mitigation Alternative

ASTM C 1260 ASTM C 1293

at 380C Accelerated C 1293 at 600C

Specified Period of Evaluation 14-Days 2-Years 26-Weeks

Class C Fly Ash 0.10% 0.040% 0.040%

Class F Fly Ash 0.10% 0.040% 0.040%

Silica Fume 0.10% 0.040% 0.040%

Granulated Slag 0.10% 0.040% 0.040%

Calcined Clay 0.10% 0.040% 0.040%

Specified Period of Evaluation 14-Days One-Year 13-Week

Lithium Nitrate 0.10% 0.040% 0.040%

Air Entrainment 0.10% 0.040% 0.040%

Cement Na2Oequiv.

0.10% 0.040% 0.040%

Shaded area indicate results that are not available as yet

It was mentioned in Chapter 12 that the 2-years of ASTM C 1293 are not

available and that the accelerated C 1293 performed at 600C exhibited remarkable

correlation with the standard C 1293. A comparison between the results generated

using both test indicated that the accelerated procedures could be used to evaluate

mitigation alternatives. Comparison between the accelerated C 1293 and ASTM C

1260 (The mortar bar test) is presented in this section.

428

Table 13.3: Effectiveness of Mitigation Alternatives with Aggregate A4-ID Evaluated Using C 1260 and Accelerated C 1293

Cementitious Material

Replacement Level by Weight of

Cement

Aggregate A4-ID ASTM C 1260a

14-day expansion of

0.79% Highly Reactive

C 1293 at 600Cb,c

13-week expansion of

0.396% Highly Reactive

Class C Fly Ash

20% H.R. H.R. 27.5% H.R. H.R. 35% S.R. S.R.

Class F Fly Ash

15% H.R. H.R. 25% S.R. S.R.

Silica Fume

5% H.R. H.R. 10% S.R. S.R.

Granulated Slag

55% Innocuous Innocuous 70% Innocuous Innocuous

Calcined Clay

17% S.R. S.R. 25% Innocuous Innocuous

Chemical Material

Dosage Volume per 1 kg of

Na2Oequiv.

Lithium Nitrate 3.5 L H.R. H.R. 4.6 L H.R. Innocuous

10.0 L S.R. Innocuous Entrained

Air 2-4% H.R. H.R. 6-8% H.R. H.R.

aH.R. = C 1260 14-day expansion > 0.20% aS.R. = 0.10% < C 1260 14-day expansion < 0.20%

aInnocuous = C 1260 14-day expansion < 0.10%

bH.R. = Accelerated C 1293 26-week expansion > 0.070% bS.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

bInnocuous = Accelerated C 1293 26-week expansion < 0.040%

cH.R. = Accelerated C 1293 13-week expansion > 0.070% cS.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

cInnocuous = Accelerated C 1293 13-week expansion < 0.040%

429

Table 13.4: Effectiveness of Mitigation Alternatives with Aggregate A2-WY Evaluated Using C 1260 and Accelerated C 1293

Cementitious Material

Replacement Level by Weight of

Cement

Aggregate A2-WY ASTM C 1260a

14-Day Expansion of

0.29% Highly Reactive

C 1293 at 600Cb,c

13-Week Expansion of

0.083% Highly Reactive

Class C Fly Ash

20% H.R. H.R. 27.5% H.R. H.R. 35% S.R. S.R.

Class F Fly Ash

15% S.R. S.R. 25% Innocuous Innocuous

Silica Fume

5% H.R. H.R. 10% S.R. S.R.

Granulated Slag

55% Innocuous Innocuous 70% Innocuous Innocuous

Calcined Clay

17% S.R. S.R. 25% Innocuous Innocuous

Chemical Material

Dosage Volume per 1 kg of

Na2Oequiv.

Lithium Nitrate3.5 L Innocuous S.R. 4.6 L Innocuous Innocuous

10.0 L Innocuous Innocuous Entrained

Air 2-4% S.R. H.R. 6-8% S.R. H.R.

aH.R. = C 1260 14-day expansion > 0.20% aS.R. = 0.10% < C 1260 14-day expansion < 0.20%

aInnocuous = C 1260 14-day expansion < 0.10%

bH.R. = Accelerated C 1293 26-week expansion > 0.070% bS.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

bInnocuous = Accelerated C 1293 26-week expansion < 0.040%

cH.R. = Accelerated C 1293 13-week expansion > 0.070% cS.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

cInnocuous = Accelerated C 1293 13-week expansion < 0.040%

430

Table 13.5: Effectiveness of Mitigation Alternatives with Aggregate C2-SD Evaluated Using C 1260 and Accelerated C 1293

Cementitious Material

Replacement Level by Weight of

Cement

Aggregate A2-WY ASTM C 1260a

14-Day Expansion of

0.17% Slowly Reactive

C 1293 at 600Cb,c

13-Week Expansion of

0.059% Slowly Reactive

Class C Fly Ash

20% S.R. S.R. 27.5% S.R. S.R. 35% Innocuous Innocuous

Class F Fly Ash

15% S.R. S.R. 25% Innocuous Innocuous

Silica Fume

5% S.R. S.R. 10% Innocuous Innocuous

Granulated Slag

55% Innocuous Innocuous 70% Innocuous Innocuous

Calcined Clay

17% Innocuous Innocuous 25% Innocuous Innocuous

Chemical Material

Dosage Volume per 1 kg of

Na2Oequiv.

Lithium Nitrate 3.5 L S.R. S.R. 4.6 L Innocuous Innocuous

10.0 L Innocuous Innocuous Entrained

Air 2-4% S.R. S.R. 6-8% S.R. S.R.

aH.R. = C 1260 14-day expansion > 0.20% aS.R. = 0.10% < C 1260 14-day expansion < 0.20%

aInnocuous = C 1260 14-day expansion < 0.10%

bH.R. = Accelerated C 1293 26-week expansion > 0.070% bS.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

bInnocuous = Accelerated C 1293 26-week expansion < 0.040%

cH.R. = Accelerated C 1293 13-week expansion > 0.070% cS.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

cInnocuous = Accelerated C 1293 13-week expansion < 0.040%

431

Results listed in Table 13.3 through 13.5 are illustrated in Figures 13.3 and 13.4.

Figure 13.3 shows how the effectiveness of Class C fly ash, Class F fly ash, silica

fume, granulated slag, and calcined clay, is evaluated using both concrete and mortar

bar tests. Figure 13.4 shows the same thing but for the use of lithium nitrate and air

entrainment.

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.000 0.040 0.080 0.120 0.160

26-Week Accelerated C 1293 Expansion, %

14-D

ya A

STM

C 1

260

Exp

ansi

on, %

Accelerated C 1293 Failure Criterion

ASTM C 1260 Failure Criterion

Figure 13.3a: Different Replacement Levels of Class C Fly Ash, Class F Fly Ash, Silica Fume, Slag, and Calcined Clay, Evaluated Using ASTM C

1260 and the Accelerated C 1293 Procedures (600C)

432

y = 4.2424x - 0.0769R2 = 0.7441

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.000 0.040 0.080 0.120 0.160

26-Week Accelerated C 1293 Expansion, %

14-D

ya A

STM

C 1

260

Exp

ansi

on, %

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.000 0.080 0.160 0.240 0.320 0.400 0.480 0.560

13-Week Accelerated C 1293 Expansion, %

14-D

ya A

STM

C 1

260

Exp

ansi

on, %

Figure 13.3b: Trend line Illustrating the Relation Between ASTM C 1260 and Accelerated C 1293 in Evaluating the Use of Class C Fly Ash, Class F

Fly Ash, Silica Fume, Slag, and Calcined Clay

Figure 13.4: Different Dosages of Air Entrainment and Lithium Nitrate, Evaluated Using ASTM C 1260 and the Accelerated C 1293 Procedures

(600C)

433

Results indicate that, with very exceptions, ASTM C 1260 and the accelerated C

1293 are producing similar results. As indicated in Table 13.3 through 13.5 using a

limit of 0.10% at 14 days for ASTM C 1260 and a limit of 0.040% at 26 weeks for

the accelerated C 1293 it was possible to generate identical results for aggregates A4-

ID, A2-WY, and C2-SD when the use of Class C fly ash, Class F fly ash, silica fume,

granulated slag, and calcined clay was being evaluated.

It was suggested in Chapter 11 that ASTM C 1260 could not be used to evaluate

the use of lithium nitrate due to the leaching of the material from the mortar bars.

This fact is further reinforced by the conflicting results between ASTM C 1260 and

the accelerated C 1293 as indicated in Tables 13.3 and 13.4 for the highly reactive

aggregates A4-ID and A2-WY. The use of lithium nitrate with the slowly reactive

aggregate C2-SD was similarly evaluated using both C 1260 and accelerated C 1293

as indicated in Table 13.5.

ASTM C 1260, C 1293, and the accelerated C 1293 seem to produce comparable

results as far as the use of air entrainment. However, a major difference was noted in

Chapter 11 and 12. When using C 1260, increasing the air entrainment content

caused a decrease in the 14-day expansion of mortar bar made with all aggregates

investigated as indicated in Figure 13.5. When using ASTM C 1293 or the

accelerated C 1293, low contents of entrained air (2 to 4%) caused an increase in the

expansions of highly reactive aggregates as indicated in Figure 13.6 and 13.7. High-

entrained air contents (6 to 8%) were required to decrease the expansions of some

highly reactive aggregates (Figures 13.6 and 13.7). As a result, it was concluded that

using ASTM C 1260 to evaluate the effect of air entrainment should be avoided

because of the misleading results.

434

0.000.100.200.300.400.500.600.700.800.901.00

A6-NM A4-ID A2-WY C2-SD B4-VA E2-IA

Investigated Aggregate

14-D

ay E

xpan

sion

, % 0% Air Entrained2-4% Air Entrained6-8% Air Entrained

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

0.800

A6-NM A4-ID A2-WYAggregate Investigated

52-W

eek

(One

-Yea

r) E

xpan

sion

, % 0% Air0-2% Air2-4% Air4-6% Air 6-8% Air

Figure 13.5: Comparison of the 14-Day C 1260 Expansions for the Different Entrained Air Levels

Figure 13.6: Comparison Between the 52-week (one-year) Expansions of the Different Aggregates and Air Entrainment Contents of Table 12.15

435

0.000

0.100

0.200

0.300

0.400

0.500

0.600

A4-ID A2-WY C2-SD A2-IA

Aggregate Investigated

13-W

eek

(3-m

onth

) Exp

ansi

on, %

0% Air2-4% Air6-8% Air

13.4 EVALUATING THE EFFECT OF CEMENT TOTAL ALKALI

CONTENT USING ASTM C 1260 AND ACCELERATED C 1293

Using different NaOH solution normalities, it was possible to evaluate the

reactivity of aggregates at different cement alkali contents using ASTM C 1260

(mortar-bar test). The accelerated C 1293, performed at 600C, was also used to

evaluate aggregate reactivity different cement alkali contents by changing the

Na2Oequiv. content of the mixtures. A comparison between the results of both tests is

presented in Table 13.6 where it can be seen that

1. The highly reactive aggregates A6-NM and A4-ID were reactive even at a

Na2Oequiv. content as low as 0.46%,

2. the highly reactive aggregate A2-WY required a 0.60% Na2Oequiv. content in

order to exhibit innocuous expansions, and

Figure 13.7: Comparison Between the 13-Week Expansions Generated Using the Accelerated C 1293 Procedures and the Different Air

Entrainment Contents

436

Table 13.6a: Effect of Na2Oequiv. Content on ASR Using ASTM C 1260

Aggregate ID

C 1260 14-Day

Expansiona

Na2Oequiv. Cement Content 1.15% 0.81% 0.46%

NaOH Solution Normality 0.75Nb 0.50Nc 0.25Nc

A6-NM 0.91% H.R.

Reactive Reactive Reactive

A4-ID 0.79% H.R.

Reactive Reactive Reactive

A2-WY 0.29% H.R.

Reactive Reactive Innocuous

C2-SD 0.17% S.R.

Reactive Reactive Innocuous

aH.R. = ASTM C 1260 14-day expansion > 0.20% aS.R. = 0.10% < ASTM C 1260 14-day expansion < 0.20%

aInnocuous = ASTM C 1260 14-day expansion < 0.10% bReactive = 14-day expansion > 0.04% ; Innocuous = 14-day expansion < 0.04% cReactive = 14-day expansion > 0.02% ; Innocuous = 14-day expansion < 0.02%

Table 12.6b: Effect of Na2Oequiv. Content on ASR Using Accelerated C 1293

Aggregate ID

C 1293 one-year Expansion

and Classification

Accelerated C 1293 13-Week Expansion and Classification

Na2Oequiv. Cement Content

1.25% 0.90% 0.60%

A6-NM 0.411% Highly Reactive

0.407% Highly Reactive H.R. H.R. S.R.

A4-ID 0.379% Highly Reactive

0.396% Highly Reactive H.R. H.R. S.R.

A2-WY 0.107% Highly Reactive

0.083% Highly Reactive H.R. S.R. Innocuous

C2-SD 0.053% Slowly Reactive

0.059% Slowly Reactive S.R. Innocuous Innocuous

H.R. = Accelerated C 1293 13-week expansion > 0.070% S.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

Innocuous = Accelerated C 1293 13-week expansion < 0.040%

437

3. The slowly reactive aggregate C2-SD exhibited innocuous expansions when

tested using accelerated C 1293 (concrete-prism test) using a cement with 0.90%

Na2Oequiv.. However, when evaluated using the C 1260 (mortar-bar test), the

slowly reactive aggregate C2-SD required a cement alkali content of 0.46% for it

to exhibit innocuous expansions. As a result, it was concluded that the C 1260 is

a conservative estimation of the effect of Na2Oequiv. content on ASR.

4. Thus, at 0.60% Na2Oequiv., moderately and slowly reactive aggregates did not

show excessive expansions due to ASR. Highly reactive aggregates were still

reactive at levels lower that 0.60%.

13.5 EVALUATING THE EFFECTIVENESS OF MITIGATION

ALTERNATIVES WITH A 0.80% Na2Oequiv. CEMENT USING ASTM C

1260 AND ACCELERATED C 1293

Using ASTM C 1260 and the accelerated C 1293 (600C) it was possible to

determine the effectiveness of the mitigation alternatives using the highly reactive (C

1260 and C 1293) aggregate A6-NM in combination with a cement with 0.80%

Na2Oequiv. content. A comparison between the results of both tests is shown in Table

13.7 where it can be noted that with the exception of Class F fly ash and lithium

nitrate the minimum requirements were the same in both tests. The concrete-prism

test required higher levels of Class f fly ash and lithium nitrate. Thus, using a low

alkali cement (lower than 0.80%) allow for more flexibility in choosing an effective

ASR mitigating measure even with the most reactive aggregates like aggregate A6-

NM.

438

Table 13.7: Effective ASR Mitigation Alternatives for Highly Reactive Aggregate A6-NM (C1260 14-day of 0.92%) Evaluated Using a Cement Alkali

Content of 0.80% Na2Oequiv.

Cementitious Material

Minimum Replacement Levels by Weight of Cement Highly Reactive Aggregate

A6-NM

Minimum Replacement Levels by Weight of Cement Highly Reactive Aggregate

A6-NM C 1260 with 0.50N NaOH

(0.81% Na2Oequiv.) Accelerated C 1293 (0.80% Na2Oequiv.)

Calcined Clay 17% 17%

Granulated Slag 50% 50%

Class F Fly Ash 20% 25%

Silica Fume 10% 10%

Class C Fly Ash 35% 35%

Chemical Admixture

Minimum LiNO3 Volume (weight) per 1 kg of Na2Oequiv.

Highly Reactive Aggregate A6-NM

Minimum LiNO3 Volume (weight) per 1 kg of Na2Oequiv.

Highly Reactive Aggregate A6-NM

0.50N NaOH (0.81% Na2Oequiv.)

Accelerated C 1293 (0.80% Na2Oequiv.)

Lithium Nitrate 3.5 L 4.6 L

Air Entrainment

Shaded Areas = Alternative could not be used

439

CHAPTER FOURTEEN

GUIDELINES AND RECOMMENDATIONS

14.1 INTRODUCTION

This chapter includes guidelines for managing the alkali-silica reactivity of

aggregates. All recommendations and courses of action were based on the testing

performed using the provided aggregate samples and information gathered from

literature review. Conclusions generated throughout the study were analyzed and

organized to produce some guiding principles, detailed in this chapter, which could

be used to predict the alkali-silica reactivity of aggregates and to mitigate the

reaction of these aggregates in concrete.

14.2 PREDICTING THE POTENTIAL ALKALI-SILICA REACTIVITY OF

AGGREGATES

Predicting the potential alkali-silica reactivity of aggregates can be accomplished

either by monitoring their field performance records or by conducting accelerated

laboratory testing. Procedures are illustrated in Figure 14.1 and detailed in the

following sections.

14.2.1 Field Performance Record

Using the field performance of a particular aggregate might be the best method for

determining whether the aggregate is alkali-silica reactive or not. Choosing an

aggregate based on its field performance should be the result of a thorough

investigation that details the field applications of the aggregate. The main idea is to

use the aggregate in a proposed concrete that is identical to a field concrete being

exposed to similar environments. The following are some considerations that should

be addressed while assessing the field performance records (Bérubé and Fournier

1993, CSA 1994 and etc.):

440

Aggregate Characterization Flow Chart I

Field Performance

History Available?

Yes

Is cement and alkali content of the

proposed concrete as high or lower than the

field concrete?

Is Aggregate Reactive in filed concrete?

Is the field concrete at least

10 years old?

Yes

Are exposure conditions of field concrete at least as severe as proposed

concrete?

Is Aggregate and W/CM in field concrete similar to that used in proposed concrete?

Yes

Yes

Yes

No

No

No

No

No

Yes

Accept Aggregate No Special Requirements

Reject or Take Preventive Measures

Flow Chart II

No

Figure 14.1: Flow Chart I for Assessing Aggregate’s Potential Alkali-Silica Reactivity

Does aggregate show 13-week expansions higher than 0.040%?

Laboratory Testing Required

Mortar-Bar-Test: ASTM C 1260

Does aggregate show 14-day expansions higher than 0.10%?

No Accept aggregate No special requirements

Yes

C 1293 at 380C C 1293 at 600C

Does aggregate show 1-year expansions

higher than 0.040%?

Yes

OR

No

Yes

No

Reject or Take Preventive Measures

Flow Chart II OR If time is available

Yes

Note: Use ASTM C 295 to verify the results of C 1260 and

C 1293

ASTM C 295 couldn’t be

used to identify slowly

reactive aggregates

441

1. The cement content and the alkali content of the cement used in the new

proposed concrete should be lower than that of field concrete,

2. Examined field concrete should be at least 10 years old,

3. Exposure conditions of filed concrete should be at least as severe as those of

proposed concrete,

4. The aggregate in field concrete should be identical to the aggregate used for the

proposed concrete. This should be verified by detailed documentation or by

petrographically examining field concrete,

5. The water-cementitious materials ratio used for the field concrete should be the

same as that used for the proposed concrete, and

6. Mixture proportions of field concrete, including the use of a mitigation

alternative, should be identical to the proportions of the proposed concrete.

If all the above conditions are satisfied than the field performance record of the

aggregate can be used to determine its potential alkali-silica reactivity:

1. If the aggregate in the field concrete was alkali-silica reactive and has been

identified as the major cause of ASR damage, then the aggregate should not be

used in the proposed concrete or preventive measures should be considered.

2. If the aggregate in the field concrete was not alkali-silica reactive and has never

been identified as being the major cause of ASR damage, then the aggregate can

be used in the proposed concrete.

3. Reactivity of aggregates in field applications could be verified using SHRP C-

315 (Lead-State Team, 1999), Handbook for the Identification of Alkali-Silica

Reactivity in Highway Structures.

The field performance record could not be used to determine the degree of alkali-

silica reactivity. It is simply used to determine whether the aggregate has shown

signs of ASR in field applications. In addition, the conditions mentioned above are

442

usually very hard to determine since information is often not available. That is why,

predicting the potential reactivity of aggregates using accelerated laboratory testing

is very useful.

14.2.2 Laboratory Testing

Results generated throughout this study indicate that there are three testing

procedures that could be used solely or in combination in order to determine the

potential alkali-silica reactivity of aggregates. These tests are ASTM C 1260 (two-

week mortar bar test), ASTM C 1293 (52-week concrete prism test), and an

accelerated C 1293 (13-week concrete prism test). Figure 14.1 (Flow Chart I)

illustrates the use of these tests. Petrographic analysis performed in accordance to

ASTM C 295 could not be used to identify reactive materials in slowly reactive

aggregates. ASTM C 295 could be used to verify and confirm the results generated in

accordance to C 1260 and C 1293.

ASTM C 1260 is a mortar bar test that consists of testing aggregates using a

specified gradation. The aggregate being investigated is combined with a cement to

cast three 1-in. x 1-in. x 11-in. mortar bars that are moist cured for 24 hours while in

the molds. Bars are demolded and stored for another 24 hours in water maintained at

800C. Bars are then moved to a 1N NaOH solution maintained at 800C and kept in

this solution for 14 days. Length expansions of the bars are monitored periodically

over the 14-day period of testing.

ASTM C 1293 is a concrete prism test that consists of investigating the reactivity

of an aggregate while being used in a concrete mixture. The reactive aggregate

(coarse or fine) is combined with an innocuous aggregate (coarse or fine depending

on the reactive aggregates) and a cement with an alkali content of 0.9 ± 0.1% to cast

three 3-in. x 3-in. x 11-in. concrete prisms. The cement alkali content is increased to

443

1.25% Na2Oequiv. by adding NaOH to the mixing water. A cement content of 708 ±

17 lb/yd3, a coarse aggregate oven-dry-rodded unit volume of 0.70 ± 0.20%, and a

water-cement ratio between 0.42 and 0.45 are required for concrete proportioning.

Concrete prisms are moist cured for 24 hours while still in molds. Prisms are then

demolded, measured for their initial length, and stored over water, in a sealed 6-gal

bucket with wicks on the sides (100% R.H.). Buckets are then stored in an

environmental room maintaining a temperature of 38 ± 20C. Length expansions are

monitored periodically over a period of one year.

The accelerated C 1293 consists of performing the same exact procedure as the

standard C 1293 with the exception of storing the bucket in an environmental room

maintained at 60 ± 20C. These procedures generated identical results to the standard

C 1293 but in a 3-month (13-weeks) period of time.

Identifying the potential alkali-silica reactivity of aggregates using the above

testing procedures should be performed as indicated in Figure 14.1 and Table 14.1,

while determining the degree of alkali-silica reactivity of aggregates should be

completed as illustrated in Table 14.2.

444

Table 14.1: Expansion Limits for Identifying Potentially Alkali-Silica Reactive Aggregates

ASTM C 1260 Mortar Bar Test

ASTM C 1293 Concrete Prism Test

Accelerated C 1293 Concrete Prism Test

14-day Expansion > 0.10%a,b,c

one-year Expansion > 0.040%d

13-week Expansion > 0.040%d

a Several aggregates showing 14-day expansions higher than 0.10% have not caused ASR related damage in field application concretes and exhibited one-year expansions lower than 0.040% when tested in accordance to C 1293 and 13-week expansions lower than 0.040% when tested in accordance to the accelerated C 1293. C 1293 results should prevail. b In rare occasions, some aggregates known to be reactive in field applications might exhibit 14-day expansions lower than 0.10%. This is usually caused by the removal of part of the reactive constituents of the aggregate as a result of aggregate preparation. A petrographic analysis in accordance to ASTM C 295 can be used to identify these aggregates and prevent the negative results. c An expansion limit of 0.08% after 14-day should be used with metamorphic aggregates. d An expansion limit lower than 0.040% may be required if aggregate will be used in a critical structure such as a nuclear containment or large dams (CSA 1994).

Table 14.2: Determination of the Degree of Alkali-Silica Reactivity of Aggregates

Degree of Alkali-Silica Reactivity

14-Day ExpansionUsing

ASTM C 1260b

One-Year Expansion

Using ASTM C 1293a,c

13-Week ExpansionUsing Accelerated

C 1293a,c

Highly Reactive > 0.20% > 0.070% > 0.070% Slowly Reactive 0.10% - 0.20% 0.040% - 0.070% 0.040% - 0.070%

Innocuous < 0.10% < 0.040% < 0.040% a ASTM C 1293 and accelerated C 1293 give the degree of reactivity for the combination of coarse and fine aggregates intended for the proposed concrete. If information about the combination is not available, then the degree of alkali-silica reactivity of the most expansive of the aggregates should be used to characterize the combination (CSA 1994). b ASTM C 1260 could not be used to test coarse and fine aggregate combinations. Each aggregate is tested separately and the largest test value should be used to determine the degree of alkali-silica reactivity. c If results of ASTM C 1260 and ASTM C 1293 contradict, then the results obtained using C 1293 should prevail.

445

14.3 MINIMIZING POTENTIAL FOR ASR-RELATED DAMAGE

Minimizing the potential for ASR related damage in a proposed concrete could be

achieved using a number of alternative approaches that are mainly dependent upon

the degree of alkali-silica reactivity of aggregates specified for the job. Results

generated throughout this investigation are summarized in Figure 14.3 that shows the

alternatives that passed C 1260 and the accelerated C 1293 for aggregates

investigated.

Different degrees of alkali-silica reactivity required different mitigation measures.

Mitigation alternatives included the use of sufficient amounts of Class C fly ash,

Class F fly ash, silica fume, granulated slag, and calcined clay to replace cement by

mass. Additional alternatives included the use of low alkali cement and the use of

lithium nitrate to replace a portion of the mixing water.

Effectiveness of alternatives listed in Figure 14.3 or any additional alternative

being considered for ASR mitigation should be verified using either of ASTM C

1260 (mortar-bar-test at 800C), C 1293 (concrete-prism-test at 380C), or the

accelerated C 1293 (concrete-prism-test at 600C) with the appropriate expansion

limits. These tests are also listed in Figure14.3.

When using ASTM C 1260, an alternative is considered effective in mitigating

ASR if it exhibits 14-day expansions lower than 0.10%. ASTM C 1260 can also be

used to investigate the effectiveness of lowering the alkali content of cement by

performing the test procedures using a NaOH solution molarity that corresponds to

the alkali content being investigated as determined by equation 14.1. When changing

the solution molarity, the expansion criterion should also be changed as shown in

Figure 14.2. ASTM C 1260 should not be used to evaluate the effectiveness of

lithium nitrate in mitigating ASR. Using equation 14.1 and Figure 14.2, ASTM C

446

1260 can also be used to investigate the effectiveness of a mitigation method used

with different cement alkali contents. However, it should be noted that these

procedures are quite conservative.

LmolescmwONaOH /06.0022.0

/2339.0][ ±+=− (Eq 14.1)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0 0.2 0.4 0.6 0.8 1 1.2

NaOH Solution Molarity

Exp

ansi

on C

rite

rion

, %

Figure 14.2: ASTM C 1260 Expansion Criteria Using Different NaOH Solution Molarities to Investigate Effectiveness of Cement Alkali Content

0.39 0.67 0.95 1.22 1.50 Corresponding Cement Na2Oequiv. as Determined by Eq. 14.1

447

Figure 14.3: Flow Chart II for Determining Effective Preventive Measures

Standard ASTM C 1293 Over water, 100% R.H., wicks, at 380C Expansion limit: 0.040% after 2 years

Accelerated ASTM C 1293 Over water, 100% R.H., wicks, at 600C Expansion limit: 0.040% after 26 weeks

Standard ASTM C 1260 In 1N NaOH solution at 800C Expansion limit: 0.10% after 14 days

ASR Preventive Measures Flow Chart II

Is aggregate highly

reactive?

Yes

Cement Na2Oequiv. < 0.08% - 17% Calcined Clay (min.) - 50% Slag (min.) - 25% Class F Fly Ash (min.) - 10% Silica Fume (min.) - 35% Class C Fly Ash (min.) - 4.6L of LiNO3 per 1Kg of Na2Oequ.

Higher Na2Oequiv. Cement - 25% Calcined Clay (min.) - > 55% Slag - 30% Class F Fly Ash (min.) - 50% Class C Fly Ash (min.)

Yes

No

Yes

- 17% Calcined Clay (min.) - 55% Slag (min.) - 25% Class F Fly Ash (min.) - 35% Class C Fly Ash (min.) - 10% Silica Fume (min.) - 4.6L LiNO3 per 1Kg of Na2O (min.) - < 0.90% Na2Oequiv. Cement No Special Requirements

Is aggregate slowly

reactive?

Is aggregate innocuous?

No

Yes

Is cement Na2Oequiv. less than 0.08%?

No

Verify Effectiveness of Alternative

Fly Ash, Calcined Clay, Slag, Silica Fume, or any Pozzolan

Reducing Cement Alkali Content

Standard ASTM C 1293 Over water, 100% R.H., wicks, at 380C Expansion limit: 0.040% after one year

Accelerated ASTM C 1293 Over water, 100% R.H., wicks, at 600C Expansion limit: 0.040% after 13 weeks

C 1260 with Corresponding Molarity NaOH solution at 800C: Equation 14.1 Expansion limit: Figure 14.2

Lithium Nitrate: LiNO3

448

When using ASTM C 1293, an expansion limit of 0.040% after 2 years of testing

is required to evaluate the effectiveness of supplementary cementitious materials

(SCM) such as fly ash, silica fume, granulated slag, and calcined clay. An expansion

limit of 0.040% after one year of testing should be used to evaluate the effectiveness

of air entrainment, low cement alkali content, and lithium nitrate.

When using the accelerated C 1293, an expansion limit of 0.040% after 26 weeks

of testing is required to evaluate the effectiveness of supplementary cementitious

materials (SCM) such as fly ash, silica fume, granulated slag, and calcined clay. An

expansion limit of 0.040% after 13 weeks of testing should be used to evaluate the

effectiveness of air entrainment, low cement alkali content, and lithium nitrate.

14.4 COST OF USING THE DIFFERENT MITIGATION ALTERNATIVES

Alternatives effective in mitigating ASR are listed in Figure 14.3. In this section a

comparison between the costs of using these alternatives is detailed. Table 14.3

includes the average costs used for the comparison. Assumptions used for the

comparison were as follows:

1. The cement content of the mixtures is 710 lb/yd3 (used throughout this

investigation),

2. Na2Oequiv. content in the mixtures is 3.67 kg/yd3, and

3. Cost included only cementitious materials cost and additives.

Table 14.3: Price Cost of Materials Used In Investigation Alternative Cost

Cement $70/ton Class F Fly Ash $23/ton Class C Fly Ash $26/ton

Silica Fume $0.35/lb Granulated Slag $65/ton Calcined Clay $82/ton

Lithium Nitrate $11/gal

449

Table 14.4: Cost of Using The Mitigation Alternatives for a Cementitious Material Content of 710 lb/yd3

Aggregate Reactivity Alternative

Cost of Cementitious

Materials Differential Cost

Cost of Cement Without any Replacement is $22/yd3

Highly Reactive Aggregates Used with a

Cement having an total alkali content lower than 0.80%

Na2Oequiv.

17% Calcined Clay $23/yd3 +4.54% 50% Granulated

Slag $22/yd3 +0.00%

25% Class F Fly Ash $19/yd3 -16.64%

10% Silica Fume $45/yd3 +104.54% 35% Class C Fly

Ash $18/yd3 -18.18%

4.6 L Lithium Nitrate per 1kg of

Na2Oequiv. $72/yd3 +227.27%

Highly Reactive Aggregates

Without Restriction on

Na2Oequiv. Content

25% Calcined Clay $26/yd3 +18.18% 60% Granulated

Slag $22/yd3 +0.00%

30% Class F Fly Ash $18/yd3 -18.18%

Slowly Reactive Aggregates

17% Calcined Clay $23/yd3 +4.54% 55% Granulated

Slag $22/yd3 +0.00%

25% Class F Fly Ash $19/yd3 -16.64%

10% Silica Fume $45/yd3 +104.54% < 0.90% Na2Oequiv.

Cement $22/yd3 +0.00%

+ = Increase in price of cementitious materials - = Decrease in price of cementitious materials

450

Onl

y C

emen

t

17%

Cal

cine

d C

lay

50%

Gra

nula

ted

Slag

10%

Sili

ca F

ume

25%

Cal

cine

d C

lay

60%

Gra

nula

ted

Slag

17%

Cal

cine

d C

lay

55%

Gra

nula

ted

Slag

10%

Sili

ca F

ume

25%

Cla

ss F

Fly

Ash

< 0.

90%

Na2

Oeq

uiv

Cem

ent

30%

Cla

ss F

Fly

Ash

35%

Cla

ss C

Fly

Ash

25%

Cla

ss F

Fly

Ash

4.6L Lithium Nitrate per 1kg of Na2Oequiv

0

10

20

30

40

50

60

70

80C

ost,

$/yd

^3

14.5 ONE BEST ALTERNATIVE

The comparison of the alternatives was based on cost (Table 14.4 and Figure

14.4), effectiveness (Figures 12.72 through 12.75), and workability (Tables 7.12

through 7.19). Using this information, the following conclusions can be made:

1. Highly reactive aggregates without restriction on Na2Oequiv. content: As can be

seen from Table 14.4, it is possible to mitigate ASR for these aggregates using

25% calcined clay, 60% granulated slag, and 30% class F fly ash. It can also be

noted from Table 14.4 that using 30% Class F fly ash resulted in the lowest cost

that is actually $4 lower than the concrete made using only cement. In addition,

using Class F fly ash resulted in a good workable mix as indicated in Table 7.16.

Figure 14.4: Comparison Between the Cost of the Cementitious Materials of the Different Mitigation Alternatives

Cost of Only Cement

Highly Reactive Aggregate with <0.80% Na2Oequiv Cement

Highly Reactive Agg. No Na2Oequiv restriction

Slowly Reactive Aggregate

451

Thus, using 30% Class F fly ash is the alternative of choice for this aggregate

category.

2. Highly reactive aggregates used with a cement having an total alkali content

lower than 0.80% na2oequiv: Examining Table 14.4, it can be noted that using 35%

Class C fly ash and 25% Class F fly ash resulted in the mostly economical

alternatives for this aggregate category. Both of these alternatives had good

workability as indicated in Tables 7.15 (Class C) and 7.16 (Class F).

3. Slowly reactive aggregates: As indicated in Table 14.4, using 25% Class F fly

ash was the most economical alternative for these aggregates. Workability of

concrete mixtures made using 25% Class F fly ash was very good as indicated in

Table 7.16.

The use of Class F fly ash will result in a decrease in the price of the cementitious

materials of the mix and is capable of mitigating the reactivity of all aggregates if the

necessary percentage is used. The use of Class F fly ash appears to be the best

alternative for the mitigation of ASR.

14.6 CONCLUDING REMARKS

Depending on the degree of alkali-silica reactivity of aggregates it is possible to

find an alternative that will decrease the expansion of the concrete or mortar

specimens below safe limits. Even the deleterious expansions of the mostly reactive

aggregate tested were decreased below safe limits using appropriate measures. It is

possible to determine the potential alkali-silica reactivity of aggregates and it is also

possible to mitigate even the mostly reactive aggregates. It should be noted that the

mitigation alternatives suggested apply only to the materials investigated whether

aggregates or admixtures. Properties of these aggregates and materials were

presented in Chapter 5.

452

CHAPTER FIFTEEN

SUMMARY OF CONCLUSIONS

15.1 INTRODUCTION

This chapter includes recommendations and conclusions that were generated

throughout this study. All conclusions and recommendations are based on the testing

performed using the provided aggregate samples. Conclusions and recommendations

are true for the tested aggregates and might not be adequate for different aggregates.

Each aggregate has to be tested and evaluated individually.

15.2 ASSESSING AGGREGATE REACTIVITY

The following conclusions were generated on the use of ASTM C 1260 for

predicting the potential reactivity of aggregates:

1. ASTM C 1260 is valuable in identifying aggregates with reactivity varying from

innocuous to rapidly reactive.

2. A 14-day expansion of 0.10% should be used as the limit between reactive and

innocuous aggregates. Aggregates with expansions lower than 0.10% are

considered innocuous. Aggregates with 14-day expansions between 0.10% and

0.20% are considered slowly reactive. Aggregates with 14-day expansions higher

than 0.20% are considered rapidly reactive.

3. ASTM C 1260 is too severe for some aggregates (E2-IA and E6-IN) indicating

that they are reactive while the aggregates have good field performance and pass

C 1293. With other aggregates (A10-PA, E4-NV, and E8-NM), C 1260 over-

estimated the aggregate reactivity indicating that they were highly reactive when

they were characterized as slowly reactive with the C 1293 procedures.

4. ASTM C 1260 should be used only as a screening method in combination with C

1293. C 1260 should not be solely used to determine the potential reactivity of

aggregates but should be supported by C 1293.

453

5. Increasing the testing time from 14 days to 56 days and using the limits of 0.33%

at 28 days and 0.48% at 56 days are not effective in predicting the correct

reactivity of aggregates. Slowly reactive aggregates did not pass these limits, and

Category E aggregates were still erroneously identified as reactive.

6. Using the polynomial fitting procedure for interpreting the C 1260 results is not

very accurate.

7. The Kolmogorov-Avrami-Mehl-Johnston model is more effective in representing

the C 1260 results. However, the model is a more sophisticated procedure for

generating the same conclusions as the standard C 1260 procedures. It does not

provide additional information.

8. Decreasing the normality of the testing solution can be used to determine the

effect of lowering the alkali content of cement. These procedures can also be

used to determine the effectiveness of mitigation alternatives at multiple alkali

contents. However, it should be noted that these procedures represent worst-case

scenarios and will give very conservative results.

9. An illustration of the use of ASTM C 1260 for aggregate characterization is

shown in the flow chart in Figure 15.1

The following conclusions were generated on the use of ASTM C 1293 for

predicting potential reactivity:

1. Innocuous aggregates showed one-year expansions lower than 0.040%. Slowly

reactive aggregates showed one-year expansions varying between 0.040% and

0.070%. Rapidly reactive aggregates experienced one-year expansions greater

than 0.070%.

2. E2-IA and E6-IN experienced innocuous one-year expansions lower than 0.040%

while A10-PA, E4-NV, and E8-NM exhibited one-year expansions between

0.040% and 0.070% indicating that they are slowly reactive.

3. Storing concrete prisms in a 1N NaOH solution at 800C was too severe for E2-IA

454

and E6-IN. With the exception of these two aggregates, using a 4-week

expansion limit of 0.040% allowed the correct classification of innocuous, slowly

reactive, and rapidly reactive aggregates. However, based on the results reported

in the literature, these procedures were not recommended.

4. Storing concrete prisms in a 1N NaOH solution at 380C resulted in E2-IA and

E6-IN having innocuous expansions slightly below the 0.040% limit after 26-

week of testing. The reactivity of innocuous, slowly reactive, and rapidly reactive

aggregates was correctly characterized using the 26-week expansion limit of

0.040%.

5. Storing concrete prisms over water, at 100% R.H., in sealed containers with

wicks, at 600C resulted in almost identical results as the standard C 1293 but in a

much shorter, 3 month, period of time. Using an expansion limit of 0.040% after

3 months of testing was effective, with all aggregates, in generating results

similar to the standard C 1293.

6. An illustration of the use of ASTM C 1293 for aggregate characterization is

shown in the flow chart in Figure 15.1

455

Potential Alkali-Silica Reactivity Characterization of Aggregates

ASTM C 1260 Mortar-Bar Test

Results required within 2 weeks No Time Constraint

14-day expansion > 0.20%

Innocuous Yes

No

0.10% < 14-day

expansion < 0.20%

Slowly Reactive

Yes

14-day expansion < 0.10%

Highly Reactive

Yes

No

ASTM C 1293 Concrete Prism Test

380C 600C

If ti

me

is a

vaila

ble

verif

y us

ing

AST

M C

129

3 Innocuous

One-year expansion < 0.040%

13-week expansion < 0.040%

Yes

No No

Slowly Reactive

0.040% < one-year

expansion < 0.070%

0.040% < 13-week

expansion < 0.070%

Yes

No No

Highly Reactive

One-year expansion > 0.070%

13-Week Expansion > 0.070%

Yes

Figure 15.1: Characterization of Aggregate Potential Alkali-Silica Reactivity

456

15.3 EFFECTIVE MITIGATION ALTERNATIVES

The following conclusions, summarized in Table 15.1 were generated using

ASTM C 1260 for assessing the effectiveness of mitigation alternatives:

1. Using up to 35% Class C fly ash to replace cement by weight was effective in

decreasing the 14-day expansions by about 80%. However, expansions of highly

reactive aggregates were still higher than the safe limit of 0.10%. This level was

effective with slowly reactive aggregates and one moderately reactive aggregate.

2. With the exception of A6-NM, replacing 25% of the weight of cement with Class

F fly ash was effective in decreasing the 14-day expansions of slowly and highly

reactive aggregates below 0.10%.

3. Using 10% silica fume to replace cement by weight was effective in decreasing

the 14-day expansions of slowly reactive aggregates below 0.10%. This level of

replacement was not effective with highly reactive aggregates even though it

caused a decrease in 14-day expansions of about 70%.

4. With the exception of A6-NM, replacing 55% of the cement weight with

granulated slag was effective in decreasing the 14-day expansions of slowly and

highly reactive aggregates below 0.10%. It took 70% slag in order for the 14-day

expansions of all aggregates to decrease below 0.10%.

5. Using 17% calcined clay to replace cement by weight was effective in decreasing

14-day expansions below 0.10% with slowly reactive aggregates and one highly

reactive aggregate. This level caused a decrease of about 80% in the 14-day

expansions of highly reactive aggregates. Replacing 25% of the cement weight

with calcined clay was effective in decreasing the 14-day expansions below

0.10% for slowly and highly reactive aggregates.

6. Using 2 to 4% entrained air caused between 30 and 50% decrease in the 14-day

expansions. However, 14-day expansions of the five aggregates were still much

higher than the 0.10% limit. Using 6 to 8% entrained air did not result in an

additional decrease in expansions. Entrained air was not effective in mitigating

457

deleterious expansions of slowly, moderately, or highly reactive aggregates.

Table 15.1: Effectiveness of the Mitigation Alternatives Using the 14-Day C 1260 Test with 0.10% Criteria

Cementitious Materials

Replace. Level

Aggregate, 14-day expansion, C 1260 Classification A6-NM 0.91% (H.R.)

A4-ID 0.79% (H.R.)

A2-WY 0.29% (H.R.)

C2-SD 0.17% (S.R.)

B4-VA 0.15% (S.R.)

E2-IA 0.42% (H.R.)

C 1260 Reactivity Classification

Class C Fly Ash

20% H.R. H.R. H.R. S.R. S.R. H.R. 27.5% H.R. H.R. H.R. S.R. Innocuous H.R. 35% H.R. S.R. S.R. Innocuous Innocuous S.R.

Class F Fly Ash

15% H.R. H.R. S.R. S.R. Innocuous S.R. 25% S.R. S.R. Innocuous Innocuous Innocuous Innocuous

Silica Fume

5% H.R. H.R. H.R. S.R. S.R. H.R. 10% S.R. S.R. S.R. Innocuous Innocuous S.R.

Granulated Slag

40% H.R. H.R. S.R. S.R. Innocuous S.R. 55% S.R. Innocuous Innocuous Innocuous Innocuous Innocuous 70% Innocuous Innocuous Innocuous Innocuous Innocuous Innocuous

Calcined Clay

17% S.R. S.R. S.R. Innocuous Innocuous S.R. 25% Innocuous Innocuous Innocuous Innocuous Innocuous Innocuous

Chemical Materials Dosage

Aggregate, 14-day expansion, C 1260 Classification A6-NM 0.91% (H.R.)

A4-ID 0.79% (H.R.)

A2-WY 0.29% (H.R.)

C2-SD 0.17% (S.R.)

B4-VA 0.15% (S.R.)

E2-IA 0.42% (H.R.)

Lithium Nitrate

21 g H.R. H.R. Innocuous S.R. Innocuous Innocuous 28 g H.R. H.R. Innocuous Innocuous Innocuous Innocuous 60 g H.R. S.R. Innocuous Innocuous Innocuous Innocuous

Entrained Air

4% H.R. H.R. S.R. S.R. Innocuous S.R. 8% H.R. H.R. S.R. S.R. Innocuous S.R.

H.R. = Highly Reactive = C 1260 14-day expansion > 0.20% S.R. = Slowly Reactive = 0.10% < C 1260 14-day expansion < 0.20%

Innocuous = C 1260 14-day expansion < 0.10%

7. Using a minimum of 4.6L LiNO3 to replace a volume of mixing water equal to

85% of the volume of the LiNO3 added was effective in decreasing the 14-day

expansions of slowly reactive aggregates below 0.10%. Using 10L LiNO3 was

not effective with highly reactive aggregates.

8. Increasing the water-cement ratio from 0.35 to 0.65 caused the 14-day

expansions to be highest for concretes with w/c of 0.35 and lowest with w/c of

458

0.65. For testing, aggregates with a w/c of 0.47 (standard) was used throughout

the study.

9. When the normality of solution was decreased to 0.50N and 0.35N (0.80% and

0.60% Na2Oequiv., respectively), alternatives effective in decreasing the 14-day

expansions of highly reactive aggregates below safe levels included replacing the

cement weight with a minimum of 25% calcined clay, 50% slag, 20% Class F fly

ash, 10% silica fume, or 35% Class C fly ash. Using a minimum of 4.6L LiNO3

to replace a volume of mixing water equal to 85% of the volume of the LiNO3

added was also effective at these normalities. This is illustrated in Table 15.2.

Table 15.2: Effective ASR Mitigation Alternatives for Highly Reactive Aggregate A6-NM (C1260 14-Day Expansion of 0.92%) Evaluated Using C 1260

with 0.75N, 0.50N, & 0.35N NaOH Solutions

Cementitious Material

Minimum Replacement Levels by Weight of Cement Highly Reactive Aggregate A6-NM

1N NaOH (1.5%Na2Oequiv.)

0.75N NaOH (1.15%Na2Oequiv.)

0.50N NaOH (0.81%Na2Oequiv.)

0.35N NaOH (0.60%Na2Oequiv.)

Calcined Clay 25% 25% 17% 17%

Granulated Slag 70% 55% 50% 50%

Class F Fly Ash 40% 25% 20% 20%

Silica Fume 10% 10%

Class C Fly Ash 50% 50% 35% 35%

Chemical Admixture

Minimum LiNO3 Volume (weight) per 1 kg of Na2O Highly Reactive Aggregate A6-NM

1N NaOH (1.5%Na2Oequiv.)

0.75N NaOH (1.15%Na2Oequiv.)

0.50N NaOH (0.81%Na2Oequiv.)

0.35N NaOH (0.60%Na2Oequiv.)

Lithium Nitrate 3.5 L (4.18 kg) 3.5 L (4.18 kg)

Shaded Areas = Alternative could not be used

459

The following conclusions, summarized in Table 15.3, were generated using

ASTM C 1293 for assessing the effectiveness of mitigation alternatives:

1. Class C fly ash was not an effective alternative for mitigating the alkali-silica

reactivity of highly reactive aggregates, A4-ID and A2-WY. Thirty-five percent

Class C fly ash, by weight of cement was needed to decrease the expansions of

the slowly reactive aggregate C2-SD to safe levels.

2. A minimum of 25% Class F fly ash was effective with the moderately reactive

aggregate A2-WY and the slowly reactive aggregate C2-SD but not with the

highly reactive aggregate A4-ID.

3. Silica fume was not effective with A4-ID (H.R.) and A2-WY (M.R.). A

minimum of 10% silica was required to mitigate ASR of the C2-SD (S.R.).

4. A minimum of 55% granulated slag was effective in mitigating ASR of all

aggregates investigated. Lower slag contents were not effective.

5. A minimum of 25% calcined clay was effective in mitigating ASR of all

aggregates investigated. Seventeen percent was only effective with the slowly

reactive aggregates

6. Air entrainment was not effective in mitigating ASR. Lower entrained air

contents were detrimental to the reaction causing an increase in expansion.

7. A minimum of 4.6 l per 1 kg of Na2Oequiv. in the mixture was effective in

mitigating the alkali-silica reactivity of all aggregates investigated.

8. Using a cement alkali content of 0.90% Na2Oequiv. was effective in mitigating the

alkali-silica reactivity of the slowly reactive aggregate C2-SD. An alkali content

of 0.60% Na2Oequiv. was needed to mitigate the alkali-silica reactivity of

moderately reactive aggregate A2-WY. The highly reactive aggregate A4-ID was

still showing signs of reactivity even at low alkali contents.

9. Using Class F fly ash resulted in the most economical and effective mitigation

alternative.

460

Table 15.3: Effectiveness of the Mitigation Alternatives Using the Accelerated C 1293 Criteria

Cementitious Material

Replacement Level By Weight of Cement

Aggregate ID, 13-Week Expansion, C 1293 Reactivity Classification

A4-ID 0.396% Highly

Reactive

A2-WY 0.083% Highly

Reactive

C2-SD 0.059% Slowly

Reactive

E2-IA 0.028%

Innocuous

Class C Fly Asha

20% H.R. H.R. S.R. Innocuous27.5% H.R. H.R. S.R. Innocuous35% S.R. S.R. Innocuous Innocuous

Class F Fly Asha

15% H.R. S.R. S.R. Innocuous25% S.R. Innocuous Innocuous Innocuous

Silica Fumea

5% H.R. H.R. S.R. Innocuous10% S.R. S.R. Innocuous Innocuous

Granulated Slaga

25% H.R. S.R. S.R. Innocuous55% Innocuous Innocuous Innocuous Innocuous70% Innocuous Innocuous Innocuous Innocuous

Calcined Claya

17% S.R. S.R. Innocuous Innocuous25% Innocuous Innocuous Innocuous Innocuous

Chemical Material Dosage

Aggregate ID, 13-Week Expansion, C 1293 Reactivity Classification

A4-ID 0.396% Highly

Reactive

A2-WY 0.083% Highly

Reactive

C2-SD 0.059% Slowly

Reactive

E2-IA 0.028%

Innocuous

Lithium Nitrateb 315 g H.R. S.R. S.R. Innocuous

495 g Innocuous Innocuous Innocuous Innocuous 900 g Innocuous Innocuous Innocuous Innocuous

Entrained Airb 2 - 4% H.R. H.R. S.R. Innocuous

6 - 8% H.R. H.R. S.R. InnocuousaH.R. = Accelerated C 1293 26-week expansion > 0.070% aS.R. = 0.040% < Accelerated C 1293 26-week expansion < 0.070%

aInnocuous = Accelerated C 1293 26-week expansion < 0.040%

bH.R. = Accelerated C 1293 13-week expansion > 0.070% bS.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

bInnocuous = Accelerated C 1293 13-week expansion < 0.040%

461

Table 15.3 (Cont’d): Effectiveness of the Mitigation Alternatives Using the Accelerated C 1293 Criteria

Cementitious Material

Na2Oequiv. Content

A6-NM 0.407% Highly

Reactive

A4-ID 0.396% Highly

Reactive

A2-WY 0.083% Highly

Reactive

C2-SD 0.059% Slowly

Reactive

Cementb 0.90% H.R. H.R. S.R. Innocuous0.60% S.R. S.R. Innocuous Innocuous6 - 8% H.R. H.R. S.R. Innocuous

bH.R. = Accelerated C 1293 13-week expansion > 0.070% bS.R. = 0.040% < Accelerated C 1293 13-week expansion < 0.070%

bInnocuous = Accelerated C 1293 13-week expansion < 0.040%

A summary of the minimum requirements for ASR mitigation is included in Tables

15.4 and 15.5.

462

Table 15.4: Effective ASR Mitigation Alternatives

Cementitious Material

Aggregate ID, 13-Week Accelerated C 1293 Expansion, Classification A4-ID

0.396% Highly Reactive

A2-WY 0.083%

Highly Reactive

C2-SD 0.059%

Slowly Reactive

E2-IA 0.028%

Innocuous Minimum Replacement Level by Weight of Cement

Calcined Clay 25% 25% 17% 0%

Granulated Slag 55% 55% 55% 0%

Class F Fly Ash > 25% 25% 25% 0%

Silica Fume 10% 0%

Class C Fly Ash 50% 50% 35% 0%

Cement Minimum Cement Na2Oequiv. Content

0.60% 0.90% Not Applicable

Chemical Admixture Minimum LiNO3 Volume (weight) per 1 kg of Na2Oequiv.

Lithium Nitrate 4.6 L (495 kg) 4.6 L (495 kg) 4.6 L (495 kg) 0L

Shaded Areas = Alternative could not be used

463

Table 15.5 Effective ASR Mitigation Alternatives for Highly Reactive Aggregate A6-NM (ASTM C 1293 one-year expansion of 0.411%) Using 0.80% Na2Oequiv.

Cement

Cementitious Material Minimum Replacement Levels by Weight of Cement

Calcined Clay 17%

Granulated Slag 50%

Class F Fly Ash 25%

Silica Fume 10%

Class C Fly Ash 35%

Chemical Material Minimum LiNO3 Volume (Weight) per 1 kg of Na2Oequiv.

Lithium Nitrate 4.6 L (495 kg)

Air Entrainment

Shaded Areas = Alternative could not be used

15.3 Final Remarks

After completing the testing program and examining the results, it was possible to

see how different aggregates required different procedures for the identification of

levels of ASR and for the mitigation of the reaction. Throughout the study,

procedures for predicting the alkali-silica reactivity of aggregates were detailed and

alternatives for mitigating ASR were presented. The correct identification of the

potential alkali-silica reactivity of aggregates would allow for the use of appropriate

mitigating alternatives and hence prevent excessive expansions that cause concrete

damage. In addition, the presented mitigation alternatives will allow the use of

reactive aggregates in durable concrete structures without having the risk of ASR. It

is believed that results from this study will enhance the state-of-the-art of ASR

testing and prevention and will support a more efficient use of aggregate sources.

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Appendix A:

EFFECT OF CHANGING THE CURING SOLUTION MOLARITY ON THE

RESULTS OF ASTM C 1260

465

0

0.08

0.16

0.24

0.32

0.4

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % A1-WY 1N

A1-WY 0.75NA1-WY 0.50NA1-WY 0.25N

0

0.08

0.16

0.24

0.32

0.4

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % A2-WY 1N

A2-WY 0.75NA2-WY 0.50NA2-WY 0.25N

466

00.10.20.30.40.50.60.70.80.9

1

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % A4-ID 1N

A4-ID 0.75NA4-ID 0.50NA4-ID 0.25N

00.10.20.30.40.50.60.70.80.9

11.11.2

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % A6-NM 1N

A6-NM 0.75NA6-NM 0.50NA6-NM 0.25N

467

0

0.08

0.16

0.24

0.32

0.4

0.48

0.56

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % A7-NC 1N

A7-NC 0.75NA7-NC 0.50NA7-NC 0.25N

0

0.08

0.16

0.24

0.32

0.4

0.48

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % A9-NE 1N

A9-NE 0.75NA9-NE 0.50NA9-NE 0.25N

468

0

0.08

0.16

0.24

0.32

0.4

0.48

0.56

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % A10-PA 1N

A10-PA 0.75NA10-PA 0.50N

0

0.08

0.16

0.24

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % B2-MD 1N

B2-MD 0.75NB2-MD 0.50NB2-MD 0.25N

469

0

0.08

0.16

0.24

0.32

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % B4-VA 1N

B4-VA 0.75NB4-VA 0.50NB4-VA 0.25N

0

0.08

0.16

0.24

0.32

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % C2-SD 1N

C2-SD 0.75NC2-SD 0.50NC2-SD 0.25N

470

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % D2-IL 1N

D2-IL 0.75ND2-IL 0.50ND2-IL 0.25N

00.080.160.240.320.4

0.480.560.640.72

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % E2-IA 1N

E2-IA 0.75NE2-IA 0.50NE2-IA 0.25N

471

00.080.160.240.32

0.40.480.560.640.72

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % E4-NV 1N

E4-NV 0.75NE4-NV 0.50NE4-NV 0.25N

0

0.08

0.16

0.24

0.32

0.4

0.48

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % E6-IN 1N

E6-IN 0.75NE6-IN 0.50NE6-IN 0.25N

472

00.080.160.240.320.4

0.480.560.64

0 4 8 12 16 20 24 28 32

Time, Day

Exp

ansi

on, % E8-NM 1N

E8-NM 0.75NE8-NM 0.50NE8-NM 0.25N

473

Appendix B

VARIABLES FOR THE KOLMOGOROV-AVRAMI-MEHL-JOHNSTON

MODEL USING C 1260 EXPANSIONS UP TO 28 DAYS

474

-9.0-8.0-7.0-6.0-5.0-4.0-3.0-2.0-1.00.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Ln

(K)

20% Class C27.5% Class C35% Class C15% Class F25% Class F

-10.0-9.0-8.0-7.0-6.0-5.0-4.0-3.0-2.0-1.00.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Ln

(K)

5% Silica Fume10% Silica Fume40% Slag55% Slag70% Slag

475

-10.0-9.0-8.0-7.0-6.0-5.0-4.0-3.0-2.0-1.00.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Ln

(K)

17% Calcined Clay25% Calcined Clay21g Lithium Nitrate28g lithium Nitrate60g Lithium Nitrate

-10.0-9.0-8.0-7.0-6.0-5.0-4.0-3.0-2.0-1.00.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Ln

(K)

4% Entrained Air8% Entrained AirW/C = 0.35W/C = 0.55W/C = 0.65

476

0.0

0.5

1.0

1.5

2.0

2.5

A6-NM A4-ID A2-WY C2-SD B4-VA

Con

stan

t M

20% Class C27.5% Class C35% Class C15% Class F25% Class F

0.0

0.5

1.0

1.5

2.0

2.5

A6-NM A4-ID A2-WY C2-SD B4-VA

Con

stan

t M

5% Silica Fume10% Silica Fume40% Slag55% Slag70% Slag

477

0.0

0.5

1.0

1.5

2.0

2.5

3.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Con

stan

t M

17% Calcined Clay25% Calcined Clay21g Lithium Nitrate28g lithium Nitrate60g Lithium Nitrate

0.0

0.5

1.0

1.5

2.0

2.5

3.0

A6-NM A4-ID A2-WY C2-SD B4-VA

Con

stan

t M

4% Entrained Air8% Entrained AirW/C = 0.35W/C = 0.55W/C = 0.65

478

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

-10.0 -8.0 -6.0 -4.0 -2.0 0.0Ln (K)

Con

stan

t M 20% Class C27.5% Class C35% Class C15% Class F25% Class F

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

-10.0 -8.0 -6.0 -4.0 -2.0 0.0Ln (K)

Con

stan

t M

5% Silica Fume10% Silica Fume40% Slag55% Slag70% Slag

479

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

-10.0 -8.0 -6.0 -4.0 -2.0 0.0Ln (K)

Con

stan

t M

17% Calcined Clay25% Calcined Clay21g Lithium Nitrate28g lithium Nitrate60g Lithium Nitrate

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

-10.0 -8.0 -6.0 -4.0 -2.0 0.0Ln (K)

Con

stan

t M

4% Entrained Air8% Entrained AirW/C = 0.35W/C = 0.55W/C = 0.65

480

Appendix C

EFFECTIVE LEVELS OF CEMENT REPLACEMENT WITH CLASS C FLY

ASH, CLASS F FLY ASH, AND SILICA FUME EVALUATED USING THE

K-M-A-J’S MODEL FOR A6-NM, A4-ID,

A2-WY, C2-SD, AND B4-VA

481

A6-NM, Highly Reactive Aggregate

-8

-7

-6

-5

-4

-3

-2

-1

0

0 20 40 60 80 100 120Percent Replacemnt of Cement by Weight

ln(k

)

Class C Fly AshClass F Fly AshSilica Fume

A4-ID, Highly Reactive Aggregate

-8

-7

-6

-5

-4

-3

-2

-1

0

0 20 40 60 80 100 120

Percent Replacement of Cement by Weight

ln(k

) Class C Fly AshClass F Fly AshSilica Fume

482

A2-WY, Highly Reactive Aggregate

-8

-7

-6

-5

-4

-3

-2

-1

0

0 20 40 60 80 100 120

Percent Replacement of Cement by Weight

ln(k

)

Class C Fly AshClass F Fly AshSilica Fume

B4-VA, Slowly Reactive Aggregate

-8

-7

-6

-5

-4

-3

-2

-1

0

0 20 40 60 80 100 120Percentage Replacemnt of Cement by

Weight

ln(k

) Class C Fly AshClass F Fly AshSilica Fume

483

C2-SD, Slowly Reactive Aggregate

-8

-7

-6

-5

-4

-3

-2

-1

0

0 20 40 60 80 100 120Percentage Replacemnt of Cement by

Weight

ln(k

) Class C Fly AshClass F Fly AshSilica Fume

484

Appendix D:

Petrographic Analysis and Field Performance Documentation of Aggregates Investigated

485

WYOMING AGGREGATES: A1-WY AND A2-WY The Wyoming DOT provided a coarse (A1-WY) and a fine aggregate (A2-WY) from the same source. The aggregate is a rhyolite and has been used extensively in the Wyoming area in structures varying from sidewalks to highway structures. It was reported that this aggregate is alkali-silica reactive. It was used in a section of Interstate 80 (I 80) and the section was heavily deteriorated due mainly to ASR. Since than the deteriorated section was removed and replaced using non-reactive aggregates. It was also reported that signs of ASR, caused by the reactivity of this aggregate, can be seen all over the Wyoming area namely in sidewalks, poles, and driveways. IDAHO AGGREGATES: A3-ID AND A4-ID The Idaho DOT provided a coarse (A3-ID) and a fine (A4-ID) aggregate from the same source. The aggregate is a combination of quartzite, sandstone, limestone, andesite, and rhyolite. This aggregate is a Snake River deposit. Historically aggregates from that river were used in bridge deck sections of the US 26. The decks were heavily deteriorated due to ASR. Recent use of the aggregate is confined asphalt hot mixes and chip seals. However, there are several occasions where the aggregate was used in portland cement concrete. “In 1993 aggregate from the source being investigated was used in two concrete bridge deck, the lower Payette Canal and Payette River Slough bridge decks. For the lower Payette Canal Deck, Type K cement was used to evaluate its effect on shrinkage cracking. No fly ash nor other ASR mitigation measures were used in either deck, except that low alkali cement was specified. Chip seals are present, so the full deck surface is not visible. According to the most recent maintenance inspection reports (in 1998), “the chip seals are worn away in some spots and there are narrow bare strips along the curbs. Some cracking is visible (more cracking on deck w/o type K), but at this point it appears to be shrinkage cracking rather than the more irregular map cracking. This leads us to believe that ASR, if present, isn’t very far advanced at this time (Stanley, A.F. 1999 Interview).” ASTM C 1260 results for both the coarse and fine aggregates were also reported. Mortar bars were not stored in hot water before storing them in the 1N NaOH solution. For the fine aggregate the 14-day expansions reported were 0.78% and 0.92%. The reported 14-day expansions for the coarse aggregates were 0.69% and 0.70%. NEW MEXICO AGGREGATES: A5-NM (PL), A6-NM (PL), E7-NM (SA),

AND E8-NM (SA) There were two aggregates that originated from New Mexico. Coarse and fine aggregate samples from each aggregate were made available for investigating. The following is a presentation of their reported properties.

486

Petrographic Analysis: A5-NM and A6-NM Petrographic examination of A5-NM (coarse) and A6-NM (fine) indicates a volcanic-and-metamorphic-rock suite of rocks in the coarse aggregate. The coarse-aggregate fractions are dominated by various tuffs, andesites, and basalts of volcanic origins, and gneisses and metaquartzites of metamorphic origin. Each sieve fraction contains potentially alkali-reactive constituents, mainly tuffs and andesites having a wide range in percentages of crystals, devitrified glass, and rock (lithic) fragments. Almost all of the tuffs are devitrified, that is, the glass that once comprised the volcanic ash shards has crystallized and compressed, forming unusually small crystals of cristoballite and other silica minerals, now making up a silica-rich matrix showing only hints of the previously particulate rock. Numerous potentially reactive andesitic rocks having an extremely finely microcrystalline matrix (in which the larger crystals are set), make up roughly 30% of the andesite-basalt category. Within the gneiss category are several varieties of finely crystalline, banded rocks in which the mineral constituents exhibit the effects of directed metamorphic stresses. These particular aggregates are also potentially reactive. Chert (microcrystalline and chalcedonic quartz) was noted in some of the sieve fractions. Its microcrystalline structure clearly suggests potential alkali reactivity.

Thus, in general, approximately 20 to 30% of the A5-NM and A6-NM materials in each of the sieve intervals are easily classified as potentially reactive. Approximately 99% of the aggregate particles are considered very hard and durable, showing little tendency to break apart. No caliche coatings were observed. The large majority of the particles are equidimensional to slightly elongated and flattened. Particle surfaces are generally smooth, except where the particle has been crushed. These morphologies typically produce concrete mixes having a normal water demand.

487

Percentages of Constituents in Each Sieve Fraction of A5-NM Retained on: 3/4 1/2 3/8 No. 4

Tuffs 3.0 6.2 7.1 3.7 Rhyolite and Trachyte 7.1 14.9 7.7 6.4 Andesite and Basalt 38.5 37.9 41.8 52.1 Granite and Syenite 8.9 7.5 10.6 12.2 Diabase 0.6 - - - Gneiss 8.9 3.7 7.1 4.3 Metaquartzite 28.4 26.7 14.7 10.1 Metaporphyry 1.2 1.2 2.9 - Feldspar - - 2.9 6.4 Quartz - - 1.8 2.7 Chert 0.6 - - 1.6 Limestone - - - 0.5 Sandstone, Siltstone 3.0 1.9 3.5 -

Percentages of Constituents in Each Sieve Fraction of A6-NM Retained on: No.8 16 30 50 100 Dust

Tuffs 7.1 3.1 6.8 2.1 2.8 - Rhyolite and Trachyte 3.3 2.6 1.2 - - - Andesite and Basalt 44.2 36.5 24.1 18.6 22.2 26.1 Granite and Syenite 11.7 8.3 7.4 3.6 1.1 - Diabase - - - 0.5 - - Gneiss 4.6 5.7 1.9 4.1 3.3 - Metaquartzite 3.9 8.2 3.1 5.7 2.8 - Metaporphyry 8.4 2.1 - 1.6 0.6 - Feldspar 7.8 13.5 19.8 23.7 26.1 29.6 Quartz - 13.5 35.2 35.1 32.2 14.8 Chert 3.9 2.1 - - 1.1 - Limestone - 1.6 - - - - Sandstone, Siltstone 3.3 1.6 0.6 0.5 - - Shale, Argillite 2.0 - - - - - Ferro-magnesian minerals - - - 0.5 2.2 5.6 Opaque (iron-rich minerals) - - - - 1.6 6.3 Volcanic Glass - 2.1 - 4.1 3.9 14.1 Others - - - - - 3.5

488

Reported ASTM C 1260 Results A5-NM and A6-NM were reported as reactive aggregates with a 14-day expansion of 1.04% when tested using C 1260 procedures in 1997. E7-NM and E8-NM were reported as potentially reactive aggregates with a 14-day expansion of 0.34%. Field Performance A5-NM and A6-NM have been established as being reactive aggregates. As a result the aggregate is not used in Portland cement concrete structures without an ASR mitigating method. E7-NM and E8-NM have been reported as having good field performance with mitigation alternatives. NORTH CAROLINA AGGREGATE: A7-NC A coarse aggregate from North Carolina was made available for the study. The following are some of the aggregate properties that were reported. Petrographic Analysis The following is a summary of a petrographic analysis report that was completed on the aggregate in question on February 2, 1993. The types of aggregate identified are described as follows: Slate Rock Type: Light to medium green-gray and medium to dark blue-gray, very fine to fine-grained slate (argillite) Mineralogy: The mineralogy is very hard to determine due to fine-grained particles; however, it is evident that some percentage of the rock is comprised of clay, chlorite, quartz, and feldspar with a trace to 2% sulphides. Particle Shape: Angular to subangular, triangular to tabular with occasional rectangular fragments Degree of Weathering: Fresh with some weathered fragments. Deleterious Materials: This slate most likely derived much of its materials from the surrounding volcanic rocks, and therefore, may contain volcanic glass. Other: Carbonate and sulphides are present on fracture surfaces and along bedding planes and foliation planes. Tuff Rock Type: Medium gray, aphanitic (very fine-grained) and fine to medium-grained tuff/tuffaceous sediment. Mineralogy: Mineralogy is hard to determine; however, some percentage of the rock is comprised of chlorite, feldspar, epidote, and carbonate. Particle Shape: Angular to subangular. Degree of Wheathering: Fresh to slightly wheathered.

489

Deleterious Materials: Volcanic Glass may be one of the constituents of this type of rock since it is of volcanic origin. In conclusion, the minerals present in the aggregate may have potential for alkali reactivity, pending the success of ASTM C 287 tests for aggregate. Field and Laboratory Performance In the spring of 1987, members of a Federal Highway inspection tour observed extensive pattern cracking in the wing walls of the James Garrison Bridge over the Tillery on NC 24-27-73. Constructed during 1977-78, this structure exhibited no noticeable cracking in the superstructure until 1982 when cracking in the end bents and wing walls was photographed. A 1984 inspection report noted cracking on the deck, abutment, and back walls of end bents, pier caps, and columns. Cracking has continued to progress and although the cracking is most extensive in the wing walls and caps, some cracking is present in all components of the bridge structure. It has been noted that presence and condition of these cracks is worse than some 50 year old bridges. A7-NC was the coarse aggregate used for that bridge in combination with a Type I cement, widely used sand, city water, and widely used chemical admixtures. A7-NC, which is reported as a meta-argillite, is used infrequently in concrete, but easily passes the standard quality tests for wear and soundness. Intact concrete cores were taken from the structure and examined. The cores showed a compressive strength in excess of 7000 psi and cracking that is best described as pattern or map cracking. Cracks on the surface typically extend only an inch or two in depth before disappearing into a myriad of many finer cracks. Concrete specimens obtained from cores are characterized by fractured aggregates with dark rims around the coarse aggregate portion. White deposits are present on the fractured faces of the coarse aggregate. Petrographic examinations confirmed alkali-silica reactivity. It was estimated that the alkali content of the cement is 0.70%.

A7-NC was also used in the construction of NC 138 over Long Creek between Oakboro and Aquadale. NC 138 was identified as exhibiting cracking due to the alkali-aggregate reactivity of A7-NC. Because the construction records for that bridge were destroyed, an extensive laboratory-testing program was conducted in order to verify the reactivity of the aggregate. The tests performed included:

1. Petrographic Examination, ASTM C 295 and C-856 2. Rock Cylinder Test, ASTM C-586 3. Quick Chemical Test, ASTM C 289 4. Mortar Bar Test, ASTM C 227 5. Testing of Concrete Prisms, ASTM C-157

The conclusion of the testing program was that A7-NC has a high reactivity potential and that its use should be restricted to concretes with cements having an alkali content of 0.4% or less.

490

Virginia Aggregates: A8-VA and B4-VA Coarse and a fine aggregate samples from a Virginia aggregate were made available for investigating. The following is a presentation of their reported properties. Petrographic Analysis: A8-VA “The sample generally consisted of particles of Quartz, Quartzite, Granitic rock fragments, Siltstone and Sandstone. A general description of the particles is as follows: 1. Quartz: The particles display a massive crystal structure with low porosity and

permeability. They were generally rounded aggregates with smooth surfaces. The aggregate was hard and dense. Some particles had fractures that did not penetrate completely through. Particle colors included milky white, smokey brown and clear (transparent).

2. Quartzite: This aggregate displayed a granoblastic (equigranular) texture. The particles were composed of medium to fine grain sand cemented tightly in a silica matrix. Particle colors were rose, light brown and reddish brown.

3. Granite Rock: Particle shapes range from angular to rounded. Mineral constituents included quartz, mica, hornblend, and feldspar. The aggregate has good intergranular bonds and is considered to be sound and durable. Only minor evidence of weathering was noted on the surface of some particles. Particle color was generally grey.

4. Sandstone: These aggregate particles were mainly composed of angular to subrounded quartz minerals along with other fine grain ferruginous minerals. The aggregate displayed good intergranular bonds and was generally free of fractures. Particle colors were predominately brown with some gray particles.

5. Siltstone: These aggregate particles display a compact crystal structure. The grain size is approximately 1/16 to 1/256 mm (medium to very fine silt). Particle colors were brown, black, and yellow. Intergranular bonds were considered to be good.

No external coatings were noted on the aggregate. The aggregate is considered to be sound and durable (Petrographic report supplied by aggregate producer, 1999).”

491

Composition of Aggregate Sample (A8-VA) In

whole sample

Constituents 1” ¾” ½” 3/8” #4 Cdt 1 Cdt 2 TotalsSandstone 25 42 22 28 40 31 - 31 Quartz Rock 44 43 49 52 39 45 - 45 Quartzite 25 12 16 11 13 14 - 14 Granite Rock Fragments 6 1 7 6 2 4 1 5 Siltstone 0 2 6 3 6 4 - 4 Totals 100 100 100 100 100 - - 99 Average (Cdt 1) 98 - Average (Cdt 2) - 1 Cdt 1: Rock particles considered to be fresh, dense, and in good physical condition. Cdt 2: Rock particles considered sound and durable with minor weathering. Petrographic Analysis: B4-VA The sample generally consisted of particles of quartz, quartzite, granitic rock fragments, siltstone, sandstone, and natural mineral fragments. A general description of the particles is as follows: 1. Quartz: The quartz is the most abundant of all constituents contained in this

sample. Particle shapes range from angular to sub-rounded. The particle colors were milky white, brick red, rose or pink, and clear.

2. Quartzite: This aggregate displayed a granoblastic (equigranular) texture. The aggregate was composed of tightly interlocked grains of quartz. In some particles, feldspar is evident in the matrix. The quartzite is of the sedimentary type of formation. Particle colors were white, grey, reddish, and clear.

3. Granite Rock: Particle shapes range from angular to rounded. Mineral constituents included quartz, mica, hornblende, and fine grained pink feldspar. The aggregate has good intergranular bonds. Particle colors were generally grey and shades of pink and red.

4. Sandstone: The sandstone particles were mainly composed of fine grained and well-sorted quartz. Particle shape ranged from sub-rounded to rounded which were cemented in a silica matrix. Particle colors were variable between red, brown, yellow, white, and grey.

5. Siltstone: Thee aggregate particles displayed a compact crystal structure. The grain size is approximately 1/16 to 1/256 mm (medium to very fine silt). Particle colors were brown, black, and yellow.

6. Minerals: These particles were composed of natural minerals which became detached from the parent rock. Components included hornblende, feldspar, and various other ferruginous minerals.

No external coatings were noted on the aggregate. The aggregate is considered to be sound and durable.

492

Composition of Aggregate Sample (B4-VA) In whole

sample

Constituents #4 #8 #16 #30 #50 #100 Cdt 1 Cdt 2 TotalsSandstone 40 40 62 74 82 82 67 - 67 Quartz Rock 8 9 13 6 6 5 7 - 7 Quartzite 5 6 4 2 2 1 3 - 3 Granite Rock Fragments

20 22 11 4 trace trace 5 1 6

Siltstone 27 23 8 11 7 4 9 1 10 Mineral Fragments trace trace 2 3 3 8 3 - 3 Totals 100 100 100 100 100 100 - - 96 Average (Cdt 1) 94 - Average (Cdt 2) - 2 Cdt 1: Rock particles considered to be fresh, dense, and in good physical condition. Cdt 2: Rock particles considered sound and durable with minor weathering. Field Performance: A8-VA and B4-VA It was reported that these aggregates “have been on the list of approved materials for the Virginia Department of Transportation for many years.” Many fairly new concrete structures incorporate these aggregates. It was also reported that an ASR mitigation alternative is required in all used mixtures. About 10 to 15 years ago, the Virginia DOT has required the use of a pozzolan in all their Portland cement concrete mixtures namely, 20-25% Class F fly ash, 5% silica fume, and 35-50% slag. All these alternatives at these levels have been used to mitigate ASR. NEBRASKA AGGREGATES: A9-NE Samples of an aggregate composed of mixed sand and gravel and heavily used in the Nebraska area were made available for this ASR study. The following are some of the documentation that was provided with the aggregate. Petrographic Analysis: A9-NE The following is a summary of a petrographic analysis performed on A9-NE: 1. The aggregate sample is partially crushed natural gravel comprising primarily of

siliceous rocks and other fragments as indicated in the following table. 2. Major constituents of the aggregate sample include pink granite, orthoquartzite,

metaquartzite, chert, metachert and allogenic quartz. Allogenic indicates rock or mineral constituents were derived from pre-existing rocks (i.e granite) and transported to their present depositional site. This allogenic quartz becomes the major constituents of the size fraction passing the No. 30 sieve (less than 0.6mm).

493

3. Minor constituents of the aggregate sample include sandstone, siltstone/claystone, and miscellaneous volcanic rocks, igneous rocks and metamorphic rocks.

4. The crypto-to-micro-crystalline textured silica as exhibited by orthoquartzite/metaquartzite and chert/metachert as well as the microgranular to fine granular silica as exhibited by the allogenic quartz are prone to be alkali-reactive when used in concrete containing high-alkali cement paste and in concrete exposed to very moist conditions.

5. Most aggregate partcles are hard, dense, free of coatings, and are subangular to well-rounded.They appear to be frost resistant and should bond well to cement paste.

6. Test methods and petrographic description of the aggregate sample are given in the following sections of this report.

Pink granite is the most abundant constituent of the sand-gravel aggregate sample

larger than the No.30 sieve (0.6mm). It is pink-colored, coarse-grained, hypidiomorphic-granular, plutonic rock, containing quartz as the most essential mineral. Accessory minerals include plagioclase feldspar and some mafic minerals such as hornblende, mica and little iron oxide.

Orthoquartize and metaquartizite are the second most abundant constituent of the aggregate sample particularly in the coarse size fractions (retained on No.16 mesh sieve). Orthoquartzite is a sandstone comprising primarily of quartz and minor amount of feldspar, limonite, and other mafic minerals. It exhibits crypto-crystalline to micro-crystalline texture, well-sorted, well-rounded to subrounded quartz sand grains cemented in a siliceous matrix. Metaquartzite is compositionally similar to orthoquartzite except that metaquartzite has undergone metamorphism resulting in strain of quartz sand grains and cement. Metamorphism has imparted the appearance of a mosaic of interlocking quartz sand grains in metaquartzite particles.

The stained quartz sand grains exhibit undulatory extinction in thin section. The quartzites (ortho and meta) are fine-to-coarse-grained, hard and dense, tan to translucent to buff. Chert and metachert are also one of the major constituents of the sand-gravel aggregate sample. They are dull to semi-vitreous, microcrystalline sedimentary rock constitute dominantly of interlocking minute crystals of quartz. Impurities include small amount of chalcedony, mica, limonite, calcite and other minerals. The varieties of chert present in the sample are: (a) light-colored (light brown, tan, and buff) amorphous silica (opaline), (b) dark brown to black metachert, and (c) light to dark-colored porous chert.The chert/metachert are known to be alkali-reactive when used in concrete especially the crypto-and-micro-crystalline and porous varieties. Quartz (silica) is also a major constituent of the aggregate sample particularly those size fractions passing the No. 30 sieve (0.6mm). It is allogenic indicating it was formed or generated elsewhere, usually at a distant place specifically from rock

494

constituents and minerals derived from pre-existing rocks (i.e granite) and transported to their present depositional site. They are microgranular to fine granular, crystalline to crypto-crystalline silica. They exhibit vitreous to greasy luster, conchoidal fracture and an absence of cleavage. The crypto-crystalline variety includes chalcedony, agate, and opal. These kinds of minerals when used in concrete containing high-alkali cement pastes are prone to be alkali-reactive. Sandstone is a minor constituent (less than 5%) of the aggregate sample. The sandstone particles are composed of fine to coarse sand grains of quartz, feldspar, calcite , ironstone and other dark-colored minerals. The sand grains are sub-angular to well rounded and cemented primarily by secondary quartz or detrital chert grains. Sandstone grades into siltstone and claystone as particle size of the sand grains decreases. Therefore, composition of the siltstones and claystones are similar to the sandstones. The sandstone, siltstone, and claystone particles are tan to brown, generally moderately hard to hard, frequently dense to less commonly porous. Other minor constituents of the aggregate sample include mica, volcanic and igneos rocks and metamorphic rocks, schist, phyllite, hornfels) categorized as miscellaneous group. These particles are generally dark-colored, moderately hard and dense except the lineated particles.

Petrographic Composition for A9-NE Constituents

Composition of Fractions Retained on Sieves 3/8” No.4 No.8 No.16 No.30 No.50 No.100 No.200 <0.075mm% % % % % % % % %

Pink Granite 46.5 46.9 46.2 41.1 33.7 9.8 6.2 4.5 2 Orthoquartzite & Metaquartzite

27.2 35.1 30 21.8 18.7 5.9 3.7 1.9 1

Chert & Metachert

12.2 4.3 10.0 15.1 11.3 4.6 3.1 0.6 Trace

Sandstone 1.8 3.3 2.7 1.0 1.9 0 0 0 Trace Siltstone & Claystone

0.9 1.4 1.5 0.7 0.6 0 0 0 Trace

Quartz (Silica)

7.0 7.6 7.7 20.0 31.9 76.5 82.0 87.9 92.0

Miscllaneous 4.4 1.4 1.9 0.3 1.9 3.2 5.0 5.1 5.0 Total 100 100 100 100 100 100 100 100 100

Field Performance: A9-NE It was reported that A9-NE “is representative of that used in much of the pavement when Interstate I-80 was first constructed through Nebraska. The aggregate is still being used but limestone is added to mitigate reactivity. When I-80 was first constructed, about one-half was built with a mix that used only A9-NE.”

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These sections of I-80 were heavily damaged due to ASR as can be seen in the following figures.

Alkali-Silica Reaction Damage in Sections of the I-80 in Nebraska

More Alkali-Silica Reaction Damage in Sections of I-80 in Nebraska

Laboratory Performance: A9-NE Available laboratory test results indicate that the sand-gravel aggregate A9-NE complies with the majority of requirements outlined in ASTM C 33. However, the aggregate exhibit signs of being reactive with alkali and can cause potentially harmful expansions. Reported results are as follows:

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Reported ASTM C 227 Results for A9-NE Test Results ASTM C 33 Limits Comment Expansion at 1 month 0.005% Expansion at 2 months 0.016% Expansion at 3 months 0.021% 0.05% Expansion at 4 months 0.031% Expansion at 5 months 0.031% Expansion at 6 months 0.031% 0.10% Non-Reactive

Note 1: Alkali content of laboratory cement = 1.01% Na2Oequiv. Note 2: Expansion is generally considered to be excessive if it exceeds

0.05% at 3 months or 0.10 at 6 months. Expansions greater than 0.05% at 3 months should not be considered excessive where 6 month expansion remains below 0.10% (Appendix X1.1.3 ASTM C 33) Reported ASTM C 1260 Resultsfor A9-NE

Test Results Comment Coarse Aggregate Expansion at 10 days

0.058% Innocuous

Fine Aggregate Expansion at 10 days

0.290% Reactive

Aggregate Combination: 70% sand 30% Coarse Expansion at 10 days

0.174% Reactive

Note 1: W/C = 0.50 Note 2: Expansion greater than 0.10% at 10 days is considered reactive MARYLAND AGGREGATE: B1-MD AND B2-MD Coarse and fine aggregate samples from the Maryland area where made available for this ASR investigation. Properties of the aggregate are as follows. Petrographic Analysis: B1-MD AND B2-MD The following table includes a summary of a petrographic examination performed on the aggregate.

Results of Petrographic Analysis on B1-MD and B2-MD

Mineral Species Crystal/Grain Size % of Composition Comments Chlorite Feldspar Fine-Grained Together:

80 – 90 Finely Intergrown

Matted Groundmass Quartz Minor Chlorite 0.3 mm 10-20 Some “Floating

Crystals”

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Field Performance: B1-MD and B2-MD The aggregate has been used extensively in Delaware. It is well known as a slowly reactive aggregate with ASTM C 1260 expansions between 0.10% and 0.15%. It has shown to be reactive in very old structures that do not have any pozzolan or any other ASR mitigating method. However, since its identification as a slowly reactive aggregate, it has been successfully used with appropriate ASR mitigating measures. Laboratory Performance: B1-MD and B2-MD Reported C 1260 date back to 1991. A type I cement was used in combination with a water-cement ratio of 0.50. Results are listed in the following able.

Reported ASTM C 1260 Results for B1-MD and B2-MD Bar No. 4-Days 7-Days 11-Days 14-Days

1 0.041 0.062 0.086 0.112 2 0.031 0.058 0.080 0.105

Average 0.036 0.060 0.083 0.11

SOUTH DAKOTA AGGREGATES: C1-SD AND C2-SD Petrographic Analysis: C1-SD and C2-SD 1. The rock is a crushed, equi-dimentional, hand sample (2 to 3 inch) sized massive,

pink quartzite. 2. The material exhibits well-developed quartz overgrowths of the individual quartz

grains. The pink to purplish color is derived from finely disseminated iron oxide which coats the original, well-rounded quartz grains as a thin film.

Reported Optical Properties and Mineralogy: C1-SD

Minerals Vol. Color Relief Other Quartz 98% Colorless Low Quartz, quartzite sand, and cement;

undulatory extinction in most grains, unit extinction in few

Pyroxene <1 Green, yellow, Pink pleoch

m-high Diopside, pyroxene cleavage and parallel extinction

Iron Oxide <1 Red Medium Finely disseminated, coating on original sand grains

Heavy Minerals

<0.1 Browns, greens

Medium to high

Various, zircon, epidote and others

Sericite <0.1 Colorless m-low At some grain boundaries Clays <0.1 Colorless low Clay “books" 3. The aggregate has a lengthy service history of good performance as concrete

aggregate and in other construction applications.

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Field Performance: C1-SD and C2-SD In old structures, namely dams, the aggregate was found to be alkali-silica

reactive. Its reactivity is attributed to the existence of strained quartz in the aggregate, which makes it a slowly reactive aggregate that cannot be detected using the existing C 227 procedures (Buck 1983). ILLINOIS AGGREGATE: D1-IL AND D2-IL

An innocuous fine and coarse aggregate form the same source and representative of aggregates used in the Illinois area were used throughout the study. Aggregate properties are as follows: Petrographic Analysis: D1-IL and D2-IL

The aggregate is hard, massive, structureless to highly coralliferous, finely crystalline dolomite. It contains numerous fossils (corals, trilobites, crinoids, cephalopods, brachiopods, gastropods, sponges). It also contains very minor amounts of clay minerals, detrial quartz, authigenic silica and traces of carbonaceous matter (tar-like hydrocarbons) and iron-oxide compounds. It does not contain mineral assemblages that are prone to alkali-aggregate reactions.

The quarried stones have been used for many years as good, chert-free concrete aggregates, excellent aggregate source for high strength concrete, raw materials for the manufacture of high quality lime, source for ripraps, blacktop chips and mineral fillers. IOWA AGGREGATE: E2-IA Field Performance: E2-IA

The aggregate is a glacial deposit that is quite shaley and has been successfully used in concrete structures with no evidence of ASR damage. The sand aggregate was used on a 1961 paving project on U.S. Highway 18. The mix design used was an IDOT C-3 as follows for volume: 1. Cement 0.114172 2. Sand (E2-IA) 0.297395 3. Coarse 0.364593 4. Water 0.457 lb per lb 5. Cement alkali content > 0.9% Na2Oequiv. 6. Air 6.0%

The latest inspection showed that the pavement has small pop outs but no ASR evidence. Laboratory Performance: E2-IA

Reported C 1260 results show that E2-IA had a 14-day expansion of 0.33% and was classified as reactive. The average of three bars was used to get the final expansion result.

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Reported C 1293 results are listed below. The test was performed by both the IaDOT and LaFarge Corporation. Both tests resulted in 1-year concrete-prisms expansions lower than 0.04% (around 0.020%).

Reported C 1293 Results for E2-IA Testing Agency

Expansion 1-month

Expansion3-months

Expansion18-week

Expansion6-month

Expansion 9-month

Expansion12-months

IaDOT 0.017 0.019 0.019 0.022 0.026 0.027 Lafarge 0.012 0.018 0.018 0.019 0.023 0.023

NEVADA AGGREGATES: E3-NV AND E4-NV Petrographic Information: E3-NV AND E4-NV

E3,E4-NV is a glassy rhyolite that comes from Rilite aggregates. The rhyolite is a young, volcanic rock. It is an amorphous siliceous rock with more than 65% SiO2. Physically, the rhyolite consists of 80 to 90% glass and 5 to 10% voids. The minerals present, which make up from 5 to 10% of the total aggregate, are phenocrysts within the glass matrix and consist of (in order of abundance) quartz, alkali-feldspar, plagioclase, and biotite. The rhyolite is light to dark grey in color and flow-banded. It is an angular aggregate with 100% fractured faces. The aggregate is considered to be potentially deleterious. Field and Laboratory Performance

Even though the aggregate is considered deleterious when examined petrographically, it has been used successfully used in concrete structures. Petrographic examination of cores taken from an 11-year-old concrete slab that utilized E4-NV, show no evidence of ASR. This is explained by the following points that are quoted from the petrographic examination report of the cores: 1. E3,4-NV is and always has been used only with a low alkali cement (<0.6% by

weight alkalis). 2. When Rilite is used in concrete, it composes both the coarse and fine fractions of

the aggregate. It has been shown that a deleterious degree of alkali-aggregate reaction will not occur if the reactive forms of siliceous material are sufficiently abundant in the concrete to consume available alkalies in production of alkali-silica combinations of very low alkali to silica, so that they lack the capacity to develop swelling or osmotic pressure by absorption of water.

INDIANA AGGREGATE: E6-IN This aggregate has only been used either with a low alkali cement or with an ASR

mitigating method. As a results, the aggregate has been successfully used for years.

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There are no records of whether this aggregate can be used with high alkali cement and no ASR mitigating method and not show deleterious expansions. SUMMARY

The following table is a summary of the available documentation about the alkali-silica reactive of aggregates investigated in this study (Table 5.2).

Summary of Aggregates Contituents and Performance

Aggregate

Petrographic Analysis

ClassificationField

Performance Mineral Materials A(1,2)-WY Reactive Reactive Rhyolite A(3,2)-ID Reactive Reactive Quartzite, sandstone, limestone,

andesite, rhyolite A(5,6)-NM Reactive Reactive Rhyolite, andesite

A7-NC Reactive Reactive Argillite A8-VA Innocuous N.R. Quartz, quartzite, granitic rock

fragments, siltstone, sandstone, and natural mineral fragments

A9-NE Reactive Reactive Pink granite, orthoquartzite, metaquartzite, chert, metachert and

allogenic quartz A10-PA Reactive N.R.

B(1,2)-MD Reactive Reactive Chlorite feldspar, quartz, and chlorite B4-VA Innocuous N.R. Quartz, quartzite, granitic rock

fragments, siltstone, sandstone, and natural mineral fragments

C(1,2)-SD Reactive Reactive Pink quartzite, pyroxene, iron oxide, sericite, Clay

D(1,2)-IL Innocuous Good with high alkali

cement

Dolomite

E2-Ia Innocuous Good with high alkali

cement

Glacial deposit, shale

E(3,4)-NV Reactive Good with mitigation

Glassy rhyolite

E6-IN Innocuous Good with high alkali

cement

N.R.

E(7,8)-NM Reactive Good with mitigation

Rhyolite, andesite

N.R. = No Record

Appendix E

Petrographic Examination of Mortar Bars After Being Tested In Accordance

With ASTM C 1260

Introduction Thin sections from six mortar bars tested according to ASTM C 1260 were

petrographically examined for signs of ASR. Two bars contained highly reactive aggregates from Category A (A4-ID and A2-WY), two contained slowly reactive aggregates (C2-SD and B4-VA), and two contained aggregates form Category E (E2-IA and E6-IN). The two category E aggregates were determined to be innocuous in the field and using C 1293 however, showed reactive C 1260 expansions. The following is a discussion of the findings. Category A Aggregates (A4-ID and A2-WY)

Representative pictures of damage found in mortar bars made with these aggregates are shown in Figures E.1 and E.2. Evidence of ASR was not easily detected. In a few locations aggregates had internal damage and had a thin rim around the outside of aggregate particle, as seen in Figure E.1. However, even in these instances the evidence did not overwhelmingly indicate the presence of ASR.

Figure E.1: A piece of aggregate showing internal cracking and a very thin

black rim around the outside of the aggregate

Figure E.2: Cracking propagating from a piece of aggregate into an air void

indicating that there might be distress caused by aggregate expansion

Slowly Reactive Aggregates (C2-SD and B4-VA)

Thin sections taken from mortar bars containing these aggregates did not show any signs of aggregate distress. All examined aggregate particles were sound with no internal cracking and no presence of the outside rim characterizing the ASR gel. Signs of ASR damage could not be identified from examining the thin sections taken. Category E Aggregates (E2-IA and E6-IN) As mentioned earlier these aggregates were determined to be innocuous in field applications and according to C 1293; however, they tested reactive using C 1260. Figures E.3 and E.4 show typical distress found in thin sections taken from mortar bars containing these aggregates. Figure E.3 indicates that the distress was located in the paste and cracks were propagating away from an aggregate particle. No rims were identified around aggregate particles. Figure E.4 might be representative of DEF, however, it is not very clear. Examining the thin sections obtained, it was not possible to determine the cause of the excessive expansion and damage caused to the mortar bars containing these aggregates.

Figure E.3: Cracks in the paste propagating away from an aggregate particle

Figure E.4: Possible presence of DEF

Final Remarks Examining the different thin sections, it was not possible to determine the definite cause of expansions in the mortar bars. Even though the highly reactive aggregates showed some signs of aggregate distress, the evidence was not very conclusive. No evidence of ASR was found in slowly reactive aggregates and in Category E aggregates.