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Sustainable Concrete for the Illinois Tollway
Matthew D’Ambrosia, Ph.D, P.E.
August 20, 2013
www.CTLGroup.com
Mechanical Properties
ConstructabilityDurability
Sustainable Concrete Must Meet Multiple Objectives
Sustainability
• Compressive Strength• Tensile Strength• Flexural Strength• Elastic Modulus• Fracture Toughness
• Cracking• Corrosion• ASR• DEF• F-T
• Workability• Flowability• Slump Loss• Finishability• Setting
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The Role of Specifications
Prescriptive specifications limit innovation, drive the contractor and supplier to focus primarily on strength
Performance specifications allow new materials, new design approaches, and focus on durability
Can be a less expensive solution for the owner
Approach considers mechanical properties, durability, and constructability
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Sustainable Concrete Starts With Portland Cement
Every year, about a cubic yard of concrete is made for every person on the planet
Domestic cement production responsible for about 1.0% of U.S. total CO2 (3.5% globally)
Portland cement is about 90% to 95% of CO2and 85% of embodied energy in concrete
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The Cement Industry...
Has increased the efficiency of their clinkering process, reducing the CO2 to cement clinker ratio (clinker factor)
Offers a plethora of blended (ASTM C595) and performance specified (ASTM C1157) cements
Is developing new cements that may further reduce the CO2 and energy footprint
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Yet…
Roughly 0.57 tons of CO2 is liberated per ton of portland cement produced due to calcination of limestone (CaCO3)
Can reduce the energy needed to some degree, but can’t change the chemistry Or can we?????
CaCO3 → CaO + CO2 Heat
CaCO3 → CaO + C + 2O
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What About Concrete?
The solution is to reduce the amount of portland cement in concrete Reduce cement content (e.g. 564 to 470 lbs/yd3)
Increased use of SCMs such as fly ash, slag, natural pozzolans, and others
Reduce amount of concrete used
Cement ≠ strength or durability use w/c
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Cement Content and CO2Po
unds
CO
2/yd3
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Points to Emphasize
Portland cement is the major source of CO2 and embodied energy in concrete, so reduce content
Good mixture proportioning can reduce cementitious content
Use blended cements and SCMs
Create long-lasting, durable structures
Durability of FRAP and B-quality Aggregate in Pavements
Matthew D’Ambrosia, Ph.D., P.E.
August 20, 2013
www.CTLGroup.com
“Black Rock” in Concrete
Coarse portion of fractionated RAP
½” to #4
Austria – standard practicein lower lift
US Trial: Florida
1st Tollway Trial: MilwaukeeAvenue ramp – 2010
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Questions for Durability
Fines, organics, effect of washing
Asphalt agglomerations, strength
Freeze-thaw
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FRAP and B-Quality Ternary MixturesASTM C192 Mixture SummaryB1 B2 Frap A Frap B Frap C
Material lb/yd3 (SSD)
Cement 370 370 370 370 370Fly Ash 85 85 85 85 85Slag 115 115 115 115 115Coarse Aggregate 1880 1916 647 637 640Coarse Aggregate 0 0 1240 1240 1240Fine Aggregate 1190 1190 1190 1190 1190Water 238 238 228 228 228w/cm 0.42 0.42 0.40 0.40 0.40
fl. oz./cwt (100 lbs of cementitous material)
Air Entraining Agent 1.41 1.02 1.02 1.02 1.02Water Reducer 4.00 4.00 4.00 4.00 4.00
Measured Fresh PropertiesSlump, in. 0.75 2.25 1.5 2.5 2.25Air Content, % 6.5% 8.0% 7.0% 8.5% 8.0%Temperature, °F 72.8 71.2 72.3 73.7 73.8Fresh Density, lb/ft3 145.0 143.6 144.3 141.3 142.8
15%20%
20%FRAPQuality
B-A-
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Fines and organics in solution
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B-Quality compressive strength is adequate
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
7 14 28
Com
pres
sive
Str
engt
h, p
si
Concrete Age, days
B1 B2 Frap A Frap B Frap C
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Freeze-thaw performance with FRAP and B-quality aggregates was satisfactory
0
20
40
60
80
100
120
0 50 100 150 200 250 300 350
Rel
ativ
e D
ynam
ic M
odul
us (R
DM
), %
No. of Cycles
Arrow A Arrow B Arrow C Arrow AverageBluff A Bluff B Bluff C Bluff AverageVulcan A Vulcan B Vulcan C Vulcan AverageK-5 A K-5 B K-5 C K5 AverageAllied A Allied B Allied C Allied Average
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Failure in one B-quality aggregate due to one or two particles
High-Performance Concrete forBridge Decks
Matthew D’Ambrosia, Ph.D, P.E.
August 20, 2013
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The approach… C3
Enhance sustainability
Develop a spec that produces constructible HPC
Reduce or minimize cracking of the deck
Improve the resistance to chloride penetration
Provide adequate freeze-thaw resistance
All other properties should be unharmed
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Candidate Bridge Deck HPC Mixtures
BS: Standard Bridge Deck Mixture
OPT: Optimization of Aggregate Gradation
SLA: Saturated Lightweight Aggregate
SRA: Shrinkage Reducing Admixture
ULT: Combined approach (OPT + SRA + SLA)
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Target Mixtures
Mix ID: BS OPT SLA SRA ULTMaterial lb/yd3 (SSD)Cement 515 375 409 403 313Fly Ash 0 125 0 134 111Slag 110 0 136 0 154Coarse Aggregate (CM-11) 1875 1501 1714 1840 1245Coarse Aggregate (CM-16) 0 391 0 0 325Saturated Lightweight Fines 0 0 364 0 236Fine Aggregate 1160 1370 986 1323 1039Water 263 210 237 226 220Total Cementitious Content 625 500 545 536 578w/cm (including water in admixtures) 0.43 0.43 0.44 0.43 0.39
Reduce cementitious%, increase SCM%
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Slump Retention = Constructability
0
2
4
6
8
10
12
0 10 20 30 40 50 60
Slum
p, in
Elapsed time, min
BS
OPT
SLA
SRA
ULT
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Air loss monitored during trials
2%
3%
4%
5%
6%
7%
8%
9%
10%
0 10 20 30 40 50 60 70 80 90
Air
Con
tent
, %
Elapsed time, min
BS
OPT
SLA
SRA
ULT
Hardened Air
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Compressive strength gain enhanced by SCMs
0
2,000
4,000
6,000
8,000
10,000
0 7 14 21 28
Aver
age
Com
pres
sive
Str
engt
h, p
si
Concrete Age, days
BS
OPT
SLA
SRA
ULT
BS OPT SLA SRA ULT[min] [min] [min] [min] [min]
initial set: 300 458 350 537 514final set: 374 543 426 638 642
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Chloride penetration resistance (28d accelerated)
0
250
500
750
1000
1250
BS OPT SLA SRA ULTRap
id C
hlor
ide
Pene
trab
ility
, cou
lom
bs
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NEED: Measurement of cracking tendency
ASTM C1581
•Concrete shrinks around the steel ring causing tensile stress in concrete•Stress relaxes due to tensile creep•Strain measurements in steel are proportional to stress in concrete•When tensile stress exceeds strength, cracking occurs
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ASTM C1581 Interpretation
Requirement for patches: 10 daysRequirement for new decks: 28 days
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Comparison of Ring Test Results
Average Time to Cracking
0
5
10
15
20
PP-2 Patch 100 525-20 600-10-A
Tim
e, d
ays
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Role of Fibers in Restrained Shrinkage
Fibers did not have much impact on cracking time
Fibers reduced crack widths by 5x
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-100
-80
-60
-40
-20
0
20
0 10 20 30 40 50 60
Stra
in x
10-6
Time, days
BS
OPT
SLA
SRA
ULT
Crack resistance is improved
BS - Three Rings Cracked@ 12-16 days
OPT - One Ring Cracked
SLA - One Ring Cracked
SRA - None Cracked
ULT - None Cracked
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Elastic modulus or “brittleness” is reduced
5,000
5,250
5,500
5,750
6,000
6,250
BS OPT SLA SRA ULT
28 d
ay E
last
ic M
odul
us, k
si
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Linear Drying Shrinkage
-0.05
-0.04
-0.03
-0.02
-0.01
0.00
0.01
0 20 40 60 80
Leng
th C
hang
e, %
Age, days
BS-F2OPT-F2SLA-F2SRA-F2ULT-F2
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Freeze-thaw… 300+ cycles with no damage
50
60
70
80
90
100
110
0 100 200 300 400 500
RD
M, %
No. of Cycles
BSOPTSLASRAULT
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UIUC - Uniaxial Creep-Shrinkage Test
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HPC stress development is mitigated
0
50
100
150
200
250
300
350
400
450
0 2 4 6 8 10 12
Res
trai
ned
Tens
ile
Stre
ss D
evel
opm
ent,
psi
Concrete Age, days
BSSRAOPTULTSLA-F4
*
*
*w/cm significantly lower than original design, generating more early shrinkage than anticipated
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Test Method Performance Requirement Time, days
AASHTO T 22-10 4000 ≤ f’cr ≤ [f’cr + 1500] psi at 14 days 14
AASHTO T 119 Slump greater than 3" for 45 minutes after water added to cement 1
ASTM C1581-09aMinimum 28 days with no cracking
Exempt when less than 600 lb/yd3 cementitiousand a minimum of 1.5 gal/yd3 SRA is used?
28 (0)
AASHTO T 160-09 Maximum 0.03 percent after 7 days curing and 21 days drying, zeroed at the start of drying 28
AASHTO T 161(A)-08Minimum RDM of 80 percent after 300 cycles
Exempt if ASTM C457 requirements are met andaggregate is IDOT Class A+
74 (7)
AASHTO T 303 Expansion less than 0.10% at 16 daysExempt if total alkali content from cement is less than 4 lb/yd3 16 (7)
ASTM C457-11Spacing factor not exceeding 0.008-in
Specific surface not less than 600 in2/in3
Total air content not less than 4.0%7
AASHTO T 277-07 Max 1250 coulombs after 28 day accelerated curing 30
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Qualification Process Concrete SupplierMaterials
Lab
Design Proportions
Testing ok?
Lab Qualification Testing ok?
Yes
No
Yes
Tollway Approved Mixture Design
Contractor
Field Acceptance Testing ok?
Tollway Acceptance
Bid Documents:• QMP• Approved Mixture
Proportions• Materials Sources
Yes
No
Optional Preliminary
Testing
Trial Batch Testing ok?
Yes
Revise and resubmit
No
No
Lab Testing Requirements:• Slump Loss• Fresh Air Content• Compressive Strength
(determine f’cr)• Restrained Shrinkage• Drying Shrinkage• Rapid Chloride Penetrability• Freeze-Thaw Durability• Alkali Silica Reactivity• Hardened Air-Void Analysis• Petrographic Analysis• Chemical Analysis
Trial Batch Testing Requirements:(performed at batch plant)• Slump Loss• Fresh Air Content• Hardened Air-Void Analysis (optional)• Compressive Strength• Rapid Chloride Penetrability
Field Acceptance Testing Requirements:(performed at project site)• Slump• Fresh Air Content• Compressive Strength• Rapid Chloride Penetrability• Hardened Air-Void Analysis (optional)• Petrographic Analysis (optional)• Chemical Analysis (optional)
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Preliminary Steps
Materials Selection
Design Proportions
Optional Testing
Submit to Lab
Concrete SupplierMaterials
Lab
Design Proportions
Testing ok?
Yes
No
Optional Preliminary
Testing
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Mixture Qualification
Lab Qualification Testing ok?
Yes
TollwayApproved Mixture Design
Trial Batch
Testing ok?
Yes
Revise and
resubmit
No
No
Lab Testing Requirements:• Slump Loss• Fresh Air Content• Compressive Strength (determine f’cr)• Restrained Shrinkage• Drying Shrinkage• Rapid Chloride Penetrability• Freeze-Thaw Durability• Alkali Silica Reactivity• Hardened Air-Void Analysis• Petrographic and Chemical Analysis
Trial Batch Testing Requirements:(performed at batch plant)• Slump Loss• Fresh Air Content• Hardened Air-Void Analysis (optional)• Compressive Strength• Rapid Chloride Penetrability
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Implementation
Contractor
Field Acceptance Testing ok?
TollwayAcceptance
Bid Documents:• QMP• Approved Mixture Proportions• Materials Sources
Yes
No
Field Acceptance Testing Requirements:(performed at project site)• Slump• Fresh Air Content• Compressive Strength• Rapid Chloride Penetrability• Hardened Air-Void Analysis (optional)• Petrographic Analysis (optional)• Chemical Analysis (optional)
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Acknowledgements
Steve Gillen and Ross Bentsen, Illinois Tollway
Professor David Lange and William Wilson, UIUC
Jay Behnke, Greg Rohlf, Derek White, STATE Testing
Bill Vavrick, Applied Research Associates (ARA)
Local Contractors and Concrete Producers
BUILDING KNOWLEDGE. DELIVERING RESULTS.
© CTLGroup 2011. The information contained in this document is intended only for use by the individual or entity it was issued to. No part of this work may be disseminated, distributed, or reproduced in any form or by any graphic, electronic or mechanical means (including photocopying, photographing, taping, or retrieval systems) without the written permission of the author, CTLGroup, or its duly designated representatives.
