Sustainable Concrete for the Illinois Tollway. Matthew D Ambrosia, Ph.D, P.E.

Transcription

1 Sustainable Concrete for the Illinois Tollway Matthew D Ambrosia, Ph.D, P.E. August 20, 2013

2 Sustainable Concrete Must Meet Multiple Objectives Mechanical Properties Compressive Strength Tensile Strength Flexural Strength Elastic Modulus Fracture Toughness Sustainability Cracking Corrosion ASR DEF F-T Durability Constructability Workability Flowability Slump Loss Finishability Setting

3 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

4 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 CO 2 (3.5% globally) Portland cement is about 90% to 95% of CO 2 and 85% of embodied energy in concrete

5 The Cement Industry... Has increased the efficiency of their clinkering process, reducing the CO 2 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 CO 2 and energy footprint

6 Yet Roughly 0.57 tons of CO 2 is liberated per ton of portland cement produced due to calcination of limestone (CaCO 3 ) Heat CaCO 3 CaO + CO 2 Can reduce the energy needed to some degree, but can t change the chemistry Or can we????? CaCO 3 CaO + C + 2O

7 What About Concrete? The solution is to reduce the amount of portland cement in concrete Reduce cement content (e.g. 564 to 470 lbs/yd 3 ) 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

8 Cement Content and CO 2 Pounds CO 2 /yd 3

9 Points to Emphasize Portland cement is the major source of CO 2 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

10 Durability of FRAP and B-quality Aggregate in Pavements Matthew D Ambrosia, Ph.D., P.E. August 20, 2013

11 Black Rock in Concrete Coarse portion of fractionated RAP ½ to #4 Austria standard practice in lower lift US Trial: Florida 1 st Tollway Trial: Milwaukee Avenue ramp 2010

12 Questions for Durability Fines, organics, effect of washing Asphalt agglomerations, strength Freeze-thaw

13 FRAP and B-Quality Ternary Mixtures ASTM C192 Mixture Summary B1 B2 Frap A Frap B Frap C Material lb/yd 3 (SSD) Cement Fly Ash 15% Slag 20% Quality Coarse Aggregate B Coarse Aggregate A Fine Aggregate Water w/cm fl. oz./cwt (100 lbs of cementitous material) Air Entraining Agent Water Reducer Measured Fresh Properties Slump, in Air Content, % 6.5% 8.0% 7.0% 8.5% 8.0% Temperature, F Fresh Density, lb/ft % FRAP

14 Fines and organics in solution

15 B-Quality compressive strength is adequate 7,000 B1 B2 Frap A Frap B Frap C Compressive Strength, psi 6,000 5,000 4,000 3,000 2,000 1, Concrete Age, days

16 Freeze-thaw performance with FRAP and B-quality aggregates was satisfactory Arrow A Arrow B Arrow C Arrow Average Bluff A Bluff B Bluff C Bluff Average Vulcan A Vulcan B Vulcan C Vulcan Average K-5 A K-5 B K-5 C K5 Average Allied A Allied B Allied C Allied Average Relative Dynamic Modulus (RDM), % No. of Cycles

17 Failure in one B-quality aggregate due to one or two particles

18 High-Performance Concrete for Bridge Decks Matthew D Ambrosia, Ph.D, P.E. August 20, 2013

19 The approach C 3 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

20 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)

21 Target Mixtures Reduce cementitious%, increase SCM% Mix ID: BS OPT SLA SRA ULT Material lb/yd 3 (SSD) Cement Fly Ash Slag Coarse Aggregate (CM-11) Coarse Aggregate (CM-16) Saturated Lightweight Fines Fine Aggregate Water Total Cementitious Content w/cm (including water in admixtures)

22 Slump Retention = Constructability BS OPT SLA SRA ULT Slump, in Elapsed time, min

23 Air loss monitored during trials 10% Air Content, % 9% 8% 7% 6% 5% 4% 3% 2% Elapsed time, min BS OPT SLA SRA ULT Hardened Air

24 Compressive strength gain enhanced by SCMs Average Compressive Strength, psi 10,000 8,000 6,000 4,000 2,000 BS OPT SLA SRA ULT [min] [min] [min] [min] [min] initial set: final set: BS OPT SLA SRA ULT Concrete Age, days

25 Chloride penetration resistance (28d accelerated) 1250 Rapid Chloride Penetrability, coulombs BS OPT SLA SRA ULT

26 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

27 ASTM C1581 Interpretation Requirement for patches: 10 days Requirement for new decks: 28 days

28 Comparison of Ring Test Results 20 Average Time to Cracking 15 Time, days PP-2 Patch A

29 Role of Fibers in Restrained Shrinkage Fibers did not have much impact on cracking time Fibers reduced crack widths by 5x

30 Crack resistance is improved Strain x BS OPT SLA SRA ULT SLA - One Ring Cracked SRA - None Cracked OPT - One Ring Cracked BS - Three Rings days Time, days ULT - None Cracked

31 Elastic modulus or brittleness is reduced 6, day Elastic Modulus, ksi 6,000 5,750 5,500 5,250 5,000 BS OPT SLA SRA ULT

32 Linear Drying Shrinkage 0.01 Length Change, % BS-F2 OPT-F2 SLA-F2 SRA-F2 ULT-F Age, days

33 Freeze-thaw 300+ cycles with no damage RDM, % BS OPT SLA SRA ULT No. of Cycles

34 UIUC - Uniaxial Creep-Shrinkage Test

35 HPC stress development is mitigated 450 Restrained Tensile Stress Development, psi * BS SRA OPT ULT SLA-F4 * Concrete Age, days *w/cm significantly lower than original design, generating more early shrinkage than anticipated

36 Test Method Performance Requirement Time, days AASHTO T f cr [f cr ] psi at 14 days 14 AASHTO T 119 ASTM C a AASHTO T AASHTO T 161(A)-08 Slump greater than 3" for 45 minutes after water added to cement Minimum 28 days with no cracking Exempt when less than 600 lb/yd 3 cementitious and a minimum of 1.5 gal/yd 3 SRA is used? Maximum 0.03 percent after 7 days curing and 21 days drying, zeroed at the start of drying Minimum RDM of 80 percent after 300 cycles Exempt if ASTM C457 requirements are met and aggregate is IDOT Class A (0) (7) AASHTO T 303 Expansion less than 0.10% at 16 days Exempt if total alkali content from cement is less than 4 lb/yd 3 16 (7) ASTM C Spacing factor not exceeding in Specific surface not less than 600 in 2 /in 3 Total air content not less than 4.0% 7 AASHTO T Max 1250 coulombs after 28 day accelerated curing 30

37 Qualification Process Materials Concrete Supplier Design Proportions Optional Preliminary Testing Testing ok? No Yes Lab 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 Lab Qualification Testing ok? Yes No Revise and resubmit Trial Batch Testing Requirements: (performed at batch plant) Slump Loss Fresh Air Content Hardened Air-Void Analysis (optional) Compressive Strength Rapid Chloride Penetrability Trial Batch Testing ok? No Yes Tollway Approved Mixture Design Bid Documents: QMP Approved Mixture Proportions Materials Sources Contractor 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) Field Acceptance Testing ok? No Yes Tollway Acceptance

38 Preliminary Steps Materials Selection Materials Concrete Supplier Design Proportions Optional Testing Design Proportions Submit to Lab Optional Preliminary Testing Testing ok? No Yes Lab

39 Mixture Qualification 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 Lab Qualification Testing ok? Yes Trial Batch Testing ok? Yes Tollway Approved Mixture Design No No Revise and resubmit

40 Implementation Bid Documents: QMP Approved Mixture Proportions Materials Sources 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) Contractor Field Acceptance Testing ok? Yes No Tollway Acceptance

41 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

42 CTLGroup 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. BUILDING KNOWLEDGE. DELIVERING RESULTS.