TRANSPORTATION RESEARCH BOARDonlinepubs.trb.org/onlinepubs/webinars/180524.pdf · The Transportation Research Board has met the standards and requirements of the Registered Continuing

Internal Curing of Concrete Pavements: State-of-the-Practice

Thursday, May 24, 20182:00-3:30 PM ET

TRANSPORTATION RESEARCH BOARD

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requirements of the Registered Continuing Education Providers Program.

Credit earned on completion of this program will be reported to RCEP. A

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and attended the entire session. As such, it does not include content that

may be deemed or construed to be an approval or endorsement by RCEP.

Purpose

Provide an overview of the primary concepts of internal curing for concrete pavements.

Learning Objectives

At the end of this webinar, you will be able to:

• Describe the fundamentals of internally cured concrete pavements and their applications

• List the materials used for internally cured pavement applications

• Describe the process of construction for internally cured pavements

• Apply lessons learned from NYSDOT’s experience with internal curing

Internal Curing of Concrete Pavements

Transportation Research Board Webinar2:00 PM – 3:30 PM

Thursday, May 24, 2018

Sam Tyson, P.E.Concrete Pavement Engineer

FHWA Office of Preconstruction, Construction, and Pavements


TRB Committee/Webinar Sponsors –• AFD50 – Design and Rehabilitation of

Concrete Pavements• AFH50 – Concrete Pavement Construction

and Rehabilitation

Background: FHWA Publications• Internal Curing of Concrete Pavements

FHWA-HIF-16-006, August 2017https://www.fhwa.dot.gov/pavement/concrete/pubs/hif16006.pdf

…..and references cited in that document.


Jason Weiss, Oregon State University

• Introduction/Background• Mixture Design/Materials

• Quality Control• Construction

• Potential Benefits• Pavement Applications

Don Streeter, New York State DOT

• Bridge Deck Projects• Mixtures and Material

Handling• Construction QC/QA

• Performance Engineering Mixture (PEM) Specification


Samuel S. Tyson, P.E.Concrete Pavement Engineer

Office of Preconstruction, Construction, and Pavements

Federal Highway Administration1200 New Jersey Avenue, S.E. – E73-440

Washington, DC 20590

E-mail: [email protected]: 202-366-1326

Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 1 of 37

Associated Technical Brief

• This presentation was developed to accompany FHWA Tech Brief HIF-16-006

• It will discussconcepts of ICfor concretepavements including:mixture design,construction, and quality control


Outline for Today’s Talk

• We want to discuss what internal curing is and where Internal Curing may have applications

• Mixture Design • Quality Control• Emerging Potential Benefits

– Reduce Joint Damage– Reduce ASR Damage (dilution/accomodation)– Reduced Built in Stress and Curing Times

• Pavement Applications ASR = Alkali Silica Reaction


What is Internal Curing?

• Internal curing water is simply water curing where the water is provided from inside the concrete

• In the US this is typically done currently by placing water inside the porous LWA

• This can also be done using superabsorbent polymers (SAP), absorptive fibers, or recycled concrete

• However currently these technologiesare not as readily available for usein pavements as is fine LWA LWA = Lightweight Aggregate

SAP = Superabsorbent Polymer


External and Internal Curing

Cast

ro e

t al.

2009


Where Has Internal Curing Been UsedWater Tanks - Bates et al. 2012Bridge Decks - DiBella et al. 2011

Pavements - Friggle et al. 2011 Patches - Barrett et al. 2014



• We want to discuss where Internal Curing may have applications


– Potential to Reduce Joint Damage– Potential to Reduce ASR Damage (dilution/accom.)– Reduced Built in Stress and Curing Times

• Pavement Applications


How Is IC Concrete Made

• Except for LWA, IC concrete mixture design generally is identical to that of conventional concrete with similar air content, water content, and coarse aggregate content.

• Currently, IC in North America is typically achieved by replacing a portion of the conventional fine aggregate (i.e., sand) with a pre-wetted lightweight fine aggregate.

IC = Internal Curing



• We want to discuss where Internal Curing may have applications for





Mixture Design for Internal Curing

• similarities and differences between the design of a conventional 6-bag mixture (water-to-cement ratio of 0.36 and 6 percent air) and an IC mixture

• assumes 15% absorption of the FLWA

• 7 lb of IC water for every 100 lb of cementititiousmaterials.


Simple Mixture Proportioning

• Convert an existing paving mixture or a bridge deck mixture to an IC Mixture

LWA Absorption: 15.0%LWA Desorption: 85.0%

LWA Specific Gravity 1.750Cement Factor 704

Chemical Shrinkage: 0.065Degree of Hydration 1

SSD LWA Replacement 413SSD Sand Replaced 619

Internal Curing Properties

Materials Weight SG (SSD) Volume, ft3Cement 564 3.15 2.869GGBFS 115 2.99 0.616Fly Ash 0 2.64 0.000

Silica Fume 25 2.2 0.182Sand 591 2.623 3.613

Lightweight Aggregate 413 1.750 3.780Coarse Aggregate 1 1700 2.763 9.860Coarse Aggregate 2 0 2.763 0.000

Water 258 1 4.135Air 0 0 1.755

Σ 3666 - 26.810

IC Mixture Design




• Mixture Design • Quality Control• Emerging Benefits

– Potential to Reduce Joint Damage– Potential to Reduce ASR Damage (dilution/accom.)– Reduced Built in Stress and Curing Times



Measuring Aggregate Properties

• Aggregate Moisture• Surface Moisture• Aggregate Absorp.• Specific Gravity

(Relative Density)• Desorption

• Spreadsheet andStep by Step Process(Miller et al 2014)








Joint Damage and the Role of IC• Concrete pavement joints damaged by salt

3Ca(OH)2 + CaCl2 + 12H2O CaCl2·3Ca(OH)2·12H2OCalcium Oxychloride


IC and Calcium Hydroxide (CaOH2; CH)

• Ca(OH)2 forms in solution and deposits in/on aggregate• Ca(OH)2 deposits on aggregate surfaces (few to 20 µm)

as stage III begins (before set)• Ca(OH)2 will react with deicing salt


Reaction of SCM and the Role of IC

• IC provides additional water that can help to increase the cement that hydrates as well as the SCM that hydrates

• As such, IC will reduce (Ca(OH)2)and reduce jointdamage

0.25 0.30 0.35 0.40 0.45 0.50w/c

Internal CuringSealed

0.4

0.5

0.6

0.7

Deg

ree

of H

ydra

tion

at 7

2 h

(Hea

t / M

axim

um th

eore

tical

hea

t)

Castro et al. 2010








Alkali Silica Reaction (ASR) and IC• Internal Curing Benefits –

– decreases porosity through hydration,– accommodation space allows gel without pressure, – dilution (replaces reactive aggregates)

• Internal Curing Disadvantages –– Higher RH/moisture

which would enable more ASR reaction to occur

RH = Relative Humidity


Alkali Silica Reaction (ASR) and IC• Reactive (R) – Most reactive and expansive• Non Reactive Aggregate Replacement at 15 & 28% (m) –

Reduces expansion due to dilution• Internal Curing – LWA Replacement at 15 & 28% % (N)) –

more effective even than non reactive aggregateLWA providesspace for expansive gel to form

• 15% replacementis CS volume Sh

in e

t al.

2010

CS = Chemical Shrinkage








Benefits of IC - Thermal• IC makes concrete less susceptible to thermal

cracking, as “built-in” stress is reduced

Schlitter et al. 2010

Plain Concrete IC Concrete


Patching and Full Depth Panel Repair

• Field trials performed in Indiana in 2014 used IC with expanded slag aggregate in high early strength, full-depth concrete pavement patches

• Application of IC in the high early-strength patches provided a concrete with two distinct benefits when compared with conventional concrete: 1) reduced built-in stress and cracking caused by

the restraint of shrinkage, and 2) increased water curing (from inside the concrete)

after the patches are covered with curing compound and opened to traffic. 22


Patching and Full Depth Panel Repair

23








CRCP Pavements

• Potential reduction in shrinkage, modulus and curling• May result in thinner sections or increased mechanical

performance and fatigue capacity • Initial crack spacing was approximately 3x longer than

those developed in conventional sections • Longer term monitoring has shown that this difference

in crack spacing decreases over time until the spacing is on the order of 20 to 30 percent longer than that in conventional concrete.

• Cracks in internally cured concrete remain tighter than those in conventional concrete


JPCP Pavements

• IC may improve durability by reducing moisture loss and improving hydration, from the extended moisture supply provided.

• IC reduces early age shrinkage and associated plastic shrinkage cracking

• Another potential benefit to jointed pavements is a reduction in upward slab curling resulting from internal slab moisture gradients and stresses locked in at the time of set resulting from temperature gradients during curing.


Applications of IC in Pavements 1

• A number of IC pavement have been placed, primarily in the Dallas-Fort Worth area using a relatively small substitution of intermediate aggregate sizes with lightweight aggregate.

• A residential subdivision in south Fort Worth, Windsor Park, constructed in 2006-2007. A survey after 8 years in service identified no significant longitudinal or transverse cracking, plastic shrinking cracking, spalling, or other defects. In general, the pavement was in excellent condition.



• 1,400-foot section of CRCP of State Highway 121 near Dallas in 2006

• Initially the cracks in the IC had a larger spacing

• After several years, the crack spacing wassimilar to that of the conventional sections; however, the cracks remained much tighter



• A 360-acre Union Pacific intermodal terminal located 12 miles from downtown Dallaswithin the city limits of Hutchins and Wilmer

• Minor joint spalls and limited cracking have been observed. Performance has been similar to the conventional sections, with both in excellent condition.



• A residential subdivision in north Fort Worth, Alexandria Meadows North, constructed in 2006-2007.

• Project contained streets both with and without internally cured concrete.

• A field survey revealed both the internally cured concrete and conventional pavement sections were in excellent condition, with very limited cracking.

• No slab curl was identified.


Summary - 1 • ICC has been successfully used in full-scale bridge

decks and concrete pavement patching projects. • ICC has similar workability, strength and mechanical

property development, reduced stress development and cracking, and similar or improved durability when compared with conventional concrete.


Summary - 2

• Aspects of proportioning and quality control – Excel worksheets for modifying a concrete mixture and for

quantifying the properties of the aggregate– Centrifuge test has substantial benefits in obtaining

surface dry conditions– Prewetting may need to be modified for IC pavements

due to the volume of material used

• Emerging Benefits for IC in pavement– Potential to reduce joint damage caused by salt– Potential to reduce ASR damage (dilution/accommodation)– Reduced curing times


Summary - 3

• Field trials examining the use of ICC in continuously reinforced concrete pavement, white topping, and jointed plain concrete pavements.

• Specific improvements hypothesized include:– reduced shrinkage, fewer and tighter cracks, – improved fatigue resistance, and – reduced slab curling/warping

• Pavement ME Design suggests that the performance of ICC pavements should be superior to conventional concrete pavements, resulting in improved life cycle


Additional Resources http://cce.oregonstate.edu/internalcuring


Acknowledgements and Disclaimer

• These slides were developed as a part of a series for the ARA by Jason Weiss and Dennis Morian.

• These materials are provided as general information and do not constitute legal or other professional advise.

• Any use of this information in the design or selection of materials for practice should be approved by the project owner and engineering-of-record.

35

1

Internal Curing ConcreteNew York Experience

Don Streeter - NYS DOT

Group Director, Accelerated Delivery and Innovative Deployment -

Structural Materials and Research

NYSDOT - Materials Bureau

2

Concrete Problems American’s spend 4.2 billion hours a year

stuck in traffic Bridges (>25%) are structurally deficient or

functionally obsolete Highways (>33%) are in poor

or mediocre condition ASCE 2017 report D+

3

Internal Curing (IC) Consideration

IC Portland Cement Concrete (PCC) data shown to have: good flexure slightly increased strength lower permeability / increased resistivity

Consideration for use in Pavements Non-wet cured PCC

4

IC Consideration Bridge deck considerations Scaling Freeze / Thaw (F/T) Cracking / Shrinkage

Pavement considerations Cracking / Shrinkage Flexural strength

5

Factors that contribute to deck cracking:* Span length / width / geometry* Continuous spans vs. simple span* Placement (staged vs. continuous)

6

7

Factors that contribute to pavement cracking:* Slab length / thickness / geometry* Subgrade / subbase conditions* Construction practices (timely curing)

8

Lab evaluation Comparing performance characteristics

for different ages of wet curing.

Evaluated control and IC mixtures Compressive strength Freeze / Thaw Scaling Shrinkage Surface Resistivity (SR)

9

Lab evaluation Evaluated 3, 7 and 14 day characteristics Samples cast and placed in fog room.

Specific curing regimes F/T and scaling moist cure for 3, 7, or 14

days then air dried for 24 hrs prior to placing in freezer

Resistivity moist cure for 3, 7 or 14 days then air dried until 28 days of age

10

Lab evaluation - results Results Shrinkage, F/T, and scaling - no significant

difference between control and IC mixture

Strength increased for IC mixtureControl IC

3 Day Comp, psi

3050 3430

7 Day Comp, psi

3950 4140

14 Day Comp, psi

4620 5220

11

Lab evaluation - results Results (con’t)

Surface Resistivity

NYSDOT Performance Engineered Mixture (PEM) SR spec proposed:

>24 kΩ-cm for decks

>16.5 kΩ-cm for pavements

Control IC3 Day Moist, 25 Day Dry SR, kΩ-

cm21.0 22.4

7 Day Moist, 21 Day Dry SR, kΩ-cm

22.8 24.9

14 Day Moist, 14 Day Dry SR, kΩ-cm

25.7 26.7

12

IC Specification - material Use of light-weight fine aggregates as a

replacement for sand

30% substitution by volume

Contractor designed mix, semi- prescriptive

Modified High-Performance Concrete (HPC) generally used.

13

IC structural mixture Cement – Type I 500 lbs Fly Ash 135 lbs Microsilica 40 lbs Fine Aggregate – Natural Sand 782 lbs Fine Aggregate – Expanded Shale 196 lbs Coarse Aggregate – 1 & 2 Blend 1720 lbs Water 262 lbs

14

Experimental plan - decks “Experimental Features” plan for FHWA 12 projects: up to 20 decks using IC PCC Compare to companion decks of similar size

/ design Measure cracking Focus on early age cracking (typically 60

days) Success – 30% reduction of cracking

15

IC production requirements Stockpile establishment Saturated Surface Dry

(SSD) condition – minimum 15%

absorbed moisture place under sprinkler

for minimum of 48 hours

allow stockpiles to drain for 12 to 15 hours prior to use

16

IC production requirements Batching Calculate absorbed and surface moisture (paper towel test)

Adjust batch weights by absorbed moisture only Absorbed water does not affect water-to-

cementitious (w/c) ratio Requires additional bin for plant production

Handling, delivery, and placement - Follow traditional practice

17

IC production / placement Batching observations Stockpile management Batching adjustments

Handling / placing Observe any difference in

handling, placing or finishing

Curing Use standard 14 day

duration

18

Case Studies / Evaluations NY Route 9W over Vineyard Avenue NY Route 96 over Owego Creek Interstate 81 at Whitney Point Court Street over Interstate 81 Bartell Road over Interstate 81 Interstate 86 over NY Route 415 Interstate 84 over Route 6 -overlay Interstate 290 Ramp B over Interstate 190

19

Case Studies / Evaluations Interstate 81 over East Hill Road NY Route 17 Exit 90 Ramp over East

BranchDelaware River

NY Route 38B over Crocker Creek NY Route 353 over Allegheny River -barrier Interstate 87 over Route 9 and Trout Brook Interstate 81 Connectors, Fort Drum -overlay

20

Court and Spencer Streets

21

Comparison – Court & Spencer

7 day 14 day 21 day 28 day

Compressive Compressive Compressive Compressive

Strength Strength Strength Strength

ConcreteType

(MPa) (MPa) (MPa) (MPa)

Spencer Street Bridge HPC 32.6 40.8 41.9 43.5Court Street Bridge HPC-IC 33.5 42.9 45.3 48.1

Percent Improvement 2.8% 5.1% 8.1% 10.6%

Cracking – none for either bridgeScaling and F/T performance very good

22

I-87 / Route 9 and Trout Brook

23

I-87 / Route 9 and Trout Brook

24

Comparison – I-87

7 day 14 day 28 day 28 day SR F/T

Comp Comp Comp Tensile

Strength Strength Strength Strength

ConcreteType

(psi) (psi) (psi) (psi) kΩ-cm % loss

HPC 4420 5215 5910 569 28 1.2

HPC-IC 4590 5790 6750 672 145 1.1

% Improvement 3.8% 11.0% 14.2%Cracking – no transverse cracking, significant map cracking SBBarriers – used HPC NB, HPC-IC SB, both show cracking

25

Deck cracking observations IC PCC and companion decks completed

Reduced cracking observed Not consistent results for all decks Geometry, number of spans, placement

procedures all impact performance

Conclusion of experiment: Require IC for all deck mixtures

26

Pavement Considerations Move to Performance Engineered Mixtures

Shrinkage requirements included Desire for early loading – flexure Well graded aggregate portion

IC will be one means of achieving performance characteristics

27

Conclusions Saturated light weight fines can improve

PCC properties IC material must have proper moisture

Addition of IC materials Requires added production efforts / expense Does not effect the finishability of concrete Provides better hydration – more efficient use

of cement and SCM resulting in improved performance characteristics

Curing durations can be reduced

28

Thank you

Contact info:

Don Streeter

[email protected]

518-457-4593

Today’s Participants• Sam Tyson, U.S. Federal Highway

Administration, [email protected]• Jason Weiss, Oregon State University,

[email protected]• Don Streeter, New York State

Department of Transportation, [email protected]

mailto:[email protected]



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Documents

TRANSPORTATION RESEARCH BOARDonlinepubs.trb.org/onlinepubs/webinars/180524.pdf · The Transportation Research Board has met the standards and requirements of the Registered Continuing