TRANSPORTATION RESEARCH BOARD. Internal Curing of Concrete Pavements: State-ofthe-Practice. Thursday, May 24, :00-3:30 PM ET

Transcription

1 TRANSPORTATION RESEARCH BOARD Internal Curing of Concrete Pavements: State-ofthe-Practice Thursday, May 24, :00-3:30 PM ET

2 The Transportation Research Board has met the standards and requirements of the Registered Continuing Education Providers Program. Credit earned on completion of this program will be reported to RCEP. A certificate of completion will be issued to participants that have registered 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.

3 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

4 Internal Curing of Concrete Pavements Transportation Research Board Webinar 2:00 PM 3:30 PM Thursday, May 24, 2018 Sam Tyson, P.E. Concrete Pavement Engineer FHWA Office of Preconstruction, Construction, and Pavements

5 Internal Curing of Concrete Pavements TRB Committee/Webinar Sponsors AFD50 Design and Rehabilitation of Concrete Pavements AFH50 Concrete Pavement Construction and Rehabilitation

6 Internal Curing of Concrete Pavements Background: FHWA Publications Internal Curing of Concrete Pavements FHWA-HIF , August references cited in that document.

7 Internal Curing of Concrete Pavements 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

8 Samuel S. Tyson, P.E. Concrete Pavement Engineer Office of Preconstruction, Construction, and Pavements Federal Highway Administration 1200 New Jersey Avenue, S.E. E Washington, DC Phone:

9 Associated Technical Brief This presentation was developed to accompany FHWA Tech Brief HIF It will discuss concepts of IC for concrete pavements including: mixture design, construction, and quality control Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 1 of 37

10 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 Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 2 of 37

11 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 technologies are not as readily available for use in pavements as is fine LWA LWA = Lightweight Aggregate SAP = Superabsorbent Polymer Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 3 of 37

12 External and Internal Curing Castro et al Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 4 of 37

13 Where Has Internal Curing Been Used Bridge Decks - DiBella et al Water Tanks - Bates et al Pavements - Friggle et al Patches - Barrett et al Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 5 of 37

14 Outline for Today s Talk We want to discuss where Internal Curing may have applications Mixture Design Quality Control Emerging Potential Benefits Potential to Reduce Joint Damage Potential to Reduce ASR Damage (dilution/accom.) Reduced Built in Stress and Curing Times Pavement Applications Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 6 of 37

15 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 prewetted lightweight fine aggregate. IC = Internal Curing Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 7 of 37

16 Outline for Today s Talk We want to discuss where Internal Curing may have applications for Mixture Design Quality Control Emerging Potential Benefits Reduce Joint Damage Reduce ASR Damage (dilution/accomodation) Reduced Built in Stress and Curing Times Pavement Applications Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 8 of 37

17 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 cementititious materials. Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 9 of 37

18 Simple Mixture Proportioning Convert an existing paving mixture or a bridge deck mixture to an IC Mixture IC Mixture Design Materials Weight SG (SSD) Volume, ft3 Cement GGBFS Fly Ash Silica Fume Sand Lightweight Aggregate Coarse Aggregate Internal Curing Properties Coarse Aggregate LWA Absorption: Water 15.0% LWA Desorption: 85.0% Air LWA Specific Gravity Σ Cement Factor 704 Chemical Shrinkage: Degree of Hydration 1 SSD LWA Replacement 413 SSD Sand Replaced 619 Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 10 of 37

19 Outline for Today s Talk We want to discuss where Internal Curing may have applications for 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 Pavement Applications Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 11 of 37

20 Measuring Aggregate Properties Aggregate Moisture Surface Moisture Aggregate Absorp. Specific Gravity (Relative Density) Desorption Spreadsheet and Step by Step Process (Miller et al 2014) Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 12 of 37

21 Outline for Today s Talk We want to discuss where Internal Curing may have applications for Mixture Design Quality Control Emerging Potential Benefits Reduce Joint Damage Reduce ASR Damage (dilution/accomodation) Reduced Built in Stress and Curing Times Pavement Applications Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 13 of 37

22 Joint Damage and the Role of IC Concrete pavement joints damaged by salt 3Ca(OH) 2 + CaCl H 2 O CaCl 2 3Ca(OH) 2 12H 2 O Calcium Oxychloride Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 14 of 37

23 IC and Calcium Hydroxide (CaOH 2 ; 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 Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 15 of 37

24 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 joint damage Degree of Hydration at 72 h (Heat / Maximum theoretical heat) Internal Curing Sealed w/c Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 16 of Castro et al. 2010

25 Outline for Today s Talk We want to discuss where Internal Curing may have applications for Mixture Design Quality Control Emerging Potential Benefits Reduce Joint Damage Reduce ASR Damage (dilution/accomodation) Reduced Built in Stress and Curing Times Pavement Applications Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 17 of 37

26 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 Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 18 of 37

27 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 aggregate LWA provides space for expansive gel to form 15% replacement is CS volume Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 19 of 37 Shin et al CS = Chemical Shrinkage

28 Outline for Today s Talk We want to discuss where Internal Curing may have applications for Mixture Design Quality Control Emerging Potential Benefits Reduce Joint Damage Reduce ASR Damage (dilution/accomodation) Reduced Built in Stress and Curing Times Pavement Applications Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 20 of 37

29 Benefits of IC - Thermal IC makes concrete less susceptible to thermal cracking, as built-in stress is reduced Plain Concrete IC Concrete Schlitter et al Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 21 of 37

30 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 Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 22 of 37

31 Patching and Full Depth Panel Repair 23 Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 23 of 37

32 Outline for Today s Talk We want to discuss where Internal Curing may have applications for Mixture Design Quality Control Emerging Potential Benefits Reduce Joint Damage Reduce ASR Damage (dilution/accomodation) Reduced Built in Stress and Curing Times Pavement Applications Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 24 of 37

33 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 Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 25 of 37

34 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. Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 26 of 37

35 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 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. Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 27 of 37

36 Applications of IC in Pavements 2 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 was similar to that of the conventional sections; however, the cracks remained much tighter Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 28 of 37

37 Applications of IC in Pavements 3 A 360-acre Union Pacific intermodal terminal located 12 miles from downtown Dallas within 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. Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 29 of 37

38 Applications of IC in Pavements 4 A residential subdivision in north Fort Worth, Alexandria Meadows North, constructed in 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. Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 30 of 37

39 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. Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 31 of 37

40 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 Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 32 of 37

41 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 Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 33 of 37

42 Additional Resources Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 34 of 37

43 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 engineeringof-record. 35 Internal Curing for Pavements Prepared by Jason Weiss, Dennis Morian and Shree Rao Slide 35 of 37

44 1 Internal Curing Concrete New York Experience Don Streeter - NYS DOT Group Director, Accelerated Delivery and Innovative Deployment - Structural Materials and Research NYSDOT - Materials Bureau

45 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+

46 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

47 4 IC Consideration Bridge deck considerations Scaling Freeze / Thaw (F/T) Cracking / Shrinkage Pavement considerations Cracking / Shrinkage Flexural strength

48 Factors that contribute to deck cracking: * Span length / width / geometry * Continuous spans vs. simple span * Placement (staged vs. continuous) 5

49 6

50 Factors that contribute to pavement cracking: * Slab length / thickness / geometry * Subgrade / subbase conditions * Construction practices (timely curing) 7

51 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)

52 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

53 10 Lab evaluation - results Results Shrinkage, F/T, and scaling - no significant difference between control and IC mixture Strength increased for IC mixture 3 Day Comp, psi 7 Day Comp, psi 14 Day Comp, psi Control IC

54 11 Lab evaluation - results Results (con t) Surface Resistivity 3 Day Moist, 25 Day Dry SR, kωcm 7 Day Moist, 21 Day Dry SR, kωcm 14 Day Moist, 14 Day Dry SR, kωcm Control IC NYSDOT Performance Engineered Mixture (PEM) SR spec proposed: >24 kω-cm for decks >16.5 kω-cm for pavements

55 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.

56 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

57 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

58 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

59 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-tocementitious (w/c) ratio Requires additional bin for plant production Handling, delivery, and placement - Follow traditional practice

60 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

61 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

62 19 Case Studies / Evaluations Interstate 81 over East Hill Road NY Route 17 Exit 90 Ramp over East Branch Delaware 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

63 Court and Spencer Streets 20

64 Comparison Court & Spencer 21 7 day 14 day 21 day 28 day Compressive Compressive Compressive Compressive Strength Strength Strength Strength Concrete Type (MPa) (MPa) (MPa) (MPa) Spencer Street Bridge HPC Court Street Bridge HPC-IC Percent Improvement 2.8% 5.1% 8.1% 10.6% Cracking none for either bridge Scaling and F/T performance very good

65 I-87 / Route 9 and Trout Brook 22

66 23 I-87 / Route 9 and Trout Brook

67 24 Comparison I-87 Concrete Type 7 day 14 day 28 day 28 day SR F/T Comp Comp Comp Tensile Strength Strength Strength Strength (psi) (psi) (psi) (psi) kω-cm % loss HPC HPC-IC % Improvement 3.8% 11.0% 14.2% Cracking no transverse cracking, significant map cracking SB Barriers used HPC NB, HPC-IC SB, both show cracking

68 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

69 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

70 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

71 28 Thank you Contact info: Don Streeter

72 Today s Participants Sam Tyson, U.S. Federal Highway Administration, Sam.Tyson@dot.gov Jason Weiss, Oregon State University, jason.weiss@oregonstate.edu Don Streeter, New York State Department of Transportation, Donald.Streeter@dot.ny.gov

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