High Performance Concrete Specifications and Practices for Bridges (2013)

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48 Appendix B Summary of Responses to Survey Questionnaire This appendix contains a summary of the responses to the questionnaire. Only those agencies that submitted comments to the questions are listed. 1. INTRODUCTION Responses to the survey were received from the following U.S. highway agencies: Alabama Alaska Arizona California Colorado District of Columbia Florida Georgia Hawaii Idaho Illinois Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina Ohio Oklahoma Oregon Pennsylvania South Carolina South Dakota Tennessee Texas Utah Virginia Washington Wisconsin Wyoming 2. GENERAL Does your agency have a definition (formal or otherwise) for high performance concrete (HPC)? Yes: 18 agencies No: 21 agencies If yes, please provide the definition. Agency Definition Alaska Concrete with engineered properties (strength, permeability, and wear resistance) that exceed those of conventional concrete Arizona See Jaber 2007. Illinois Illinois DOT uses special mix designs for various applications. We are getting away from the term high performance concrete because it has a very broad definition which makes the connotation ambiguous. Kansas High Performance Low Cracking Concrete is a specified concrete. However the general definition/description is durable, placeable, low permeability concrete using supplemental cementitious materials with reduced cement and water and optimized gradations. Maryland Concrete that has a life cycle of 75 years or better based on durability without a need for major repair. HPC is based on less permeable mixes, not high strength. Massachusetts Please refer to subsection M4.06.1 of Supplemental Specifications to the 1988 Standard Specifications for Highways and Bridges 2010. 1.

49 Michigan Concrete that will perform better for a given application than a “standard” mix design would have. Nebraska We try to follow AASHTO definition. Nevada Typically used for bridge decks, approach slabs, and bridge rail. Our specifications require a “Contractor Quality Control Plan.” This addresses concrete production, QC testing, transport, a contingency plan for equipment failure and weather, placement, and curing. The mix design consists of a three-bin aggregate blend, cement, and 20% minimum pozzolan. Chloride permeability testing, AASHTO T 303 testing for ASR potential, and testing for all of the specific criteria established for a particular structure together with 10-day wet curing New Hampshire HPC consists of four strength-related performance characteristics (compressive strength, modulus of elasticity, shrinkage, and creep) and four durability-related performance characteristics (freeze- thaw resistance, scaling resistance, abrasion resistance, and chloride penetration). New Jersey From NJDOT Design Manual (20-1): Concrete that meets specific performance criteria New Mexico We have several “High Performance Concrete” applications. Basically, a “High Performance Concrete” mix is one that has been optimized for the performance properties required for the specific application. Our most common “High Performance Concrete” application is a “High Performance Deck” application for bridge decks and approach slabs. New York There is no specific definition for HPC although we have a mixture design defined as “HP” that is prescriptive in nature and incorporates the inclusion of 26% pozzolans to reduce thermal concerns to reduce cracking potential and to lower permeability. North Carolina Prescriptive mix design that produces concrete with low chloride permeability Ohio Our HPC mixes were designed to provide low permeability (typically 400 to 700 coulombs on the rapid chloride permeability testing). A consequence of this was high strength (typically 7,000 to 9,000 psi), but the bridge design are still based on 4,500 psi. Oregon Concrete designed for enhanced durability and performance characteristics. This definition is from section 02001.01 in the 2008 Oregon Standard Specifications for Construction. According to Section 02001.30 in these same specifications, high performance concrete mix designs must contain cementitious material with 66% portland cement, 30% fly ash, and 4% silica fume. Alternate mixes are permitted when a trial batch demonstrates the mix design provides a maximum of 1,000 coulombs at 90 days when tested according to AASHTO T 277. South Carolina Class E/6500 psi Texas Concrete that contains a minimum amount of SCM’s replacing a portion of the cement or concrete that meets a specified permeability requirement Virginia Informal definition: Concrete that has high workability (SCC), high strength (exceeding 6 ksi), and low permeability (< 2,500 coulombs for decks) How does your agency specify HPC? Select only one. Standard specifications only: 7 agencies Special provisions for all projects: No agencies Special provisions for specific projects: 15 agencies Combination of standard specifications and special provisions for all projects: 6 agencies Combination of standard specifications and special provisions for specific projects: 10 agencies Are your agency’s standard specifications for HPC prescriptive, performance-based, or a combination? Not applicable: 15 agencies Prescriptive: 8 agencies Performance: 2 agencies Combination: 12 agencies 2. 3.

50 Are your agency’s special provisions for HPC prescriptive, performance-based, or a combination? Not applicable: 8 agencies Prescriptive: 11 agencies Performance: 2 agencies Combination: 17 agencies In general, how is your agency’s HPC performing compared to conventional concrete? Bridge Element Number of Agencies Worse Same Better Not Applicable Cast-in-place concrete 2 9 22 4 Precast concrete girders 0 6 16 14 Precast concrete deck panels 0 5 8 23 What performance issues with HPC has your agency identified? Agency Cast-in-Place Concrete Precast Concrete Girders Precast Concrete Decks Alaska Mix design issues and decreased workability — — Arizona Supply, regional availability of aggregates, construction QA — — California Corrosion, ASR, shrinkage Corrosion, ASR, shrinkage — Colorado Shrinkage cracking — — District of Columbia Cracking in bridge decks — — Florida Some cracking if curing is not started at the appropriate time If curing is not initiated at the appropriate time, cracks develop. — Idaho Cracking — — Illinois Concrete may be too strong for bridge decks, which may be causing cracks. — — Iowa Shrinkage cracks — — Kansas Requires attention to details, in particular cement content, gradations, and curing requirements — — Maine Cracking and workability issues — — Minnesota Transverse deck cracking — — Nebraska — Slump consistency — Nevada Minor cracking still apparent Occasional voids still occur — 4. 5. 6.

51 New Jersey Deck cracking — — New Mexico ASR, shrinkage, heat of hydration, cracking ASR, shrinkage, heat of hydration, cracking, creep ASR, shrinkage, heat of hydration, cracking, creep New York We still see some cracking but believe it is related to the numerous variables of deck construction—not always specific to HPC although there are still concerns w/autogenous shrinkage. — No concerns with the panels themselves and HPC use Ohio Cracking — — Oklahoma — Buggy textured surface susceptible to minor cracking — Oregon Shrinkage cracking has increased. We are working to reduce/mitigate cracking using various methods. Although our girders typically use high-strength concrete, they generally do not require silica fume and we therefore would not classify the mix as high performance. — South Carolina Shrinkage cracks — — South Dakota There have been some instances of increased cracking. — — Texas Some issues during construction related to fly ash affecting air entrainment. — — Virginia SCC can segregate and lose air, HPC can provide high strengths (unintentionally) that can make concrete more prone to cracking. SCC can segregate and lose air. — Washington Deck cracking — — What specifications and practices has your agency used that resulted in improved concrete performance? Agency Specifications and Practices Alabama The Special Provision written for our only (known) HPC bridge project in 1999–2000 resulted in very good quality concrete, which appears to have performed significantly better than conventional concrete. Alaska Precast girders (high strength concrete typically f 'c > 10 ksi) appear to be very durable. We typically use the same concrete in decked girders resulting in very good deck performance. Arizona Special provision for a specific project. See Jaber 2007. California Limiting shrinkage in decks, limiting shrinkage in special structures, enhancing corrosion Colorado Lower cement contents, increased fly ash content, required wet curing for 7 days, using 56 days for strength acceptance District of Columbia Coulomb values for low permeability concrete and use of 50% slag cement 7.

52 Florida Our latest revision to Section 346 requires the use of fly ash or slag cement in all concrete. Where high strength and durability are required for a particular environmental classification, silica fume, metakaolin, or ultra fine fly ash may be required as well. Iowa Enhanced curing requirements such as longer wet cure and evaporation rate control and lower permeability through the use of mineral admixtures Kansas Maximum allowable permeability, use of SCMs, optimized aggregate gradations, and 14-day wet cure Louisiana Admixtures and cementitious substitutions: Fly ash/slag cement/silica fume Maine Implemented an ASR specification, implemented the Quality Level Analysis Specification for structural concrete Maryland Addition of fibers and corrosion inhibitors, reduction of the design compressive strength, and strict adherence to curing specifications Massachusetts Air entrainment of 6.5 ± 1.5%, target slump of 4 in., w/c ratio limited to 0.4 maximum, an addition of calcium nitrite corrosion inhibitors, use of fly ash and slag cement Michigan Implementation of supplemental cementitious materials, optimized aggregate gradations, 7-day wet cure, night placements Minnesota Performance based specification for concrete bridge decks Nebraska Use of fly ash or Class N pozzolan to mitigate ASR, used SCC concrete on precast concrete girders Nevada 10-day wet cure and 3-bin coarse aggregate gradation New Hampshire NHDOT uses the term QC/QA concrete in our specifications, which is our version of HPC. The utilization ASR testing of aggregates, permeability requirements, and strict conformance to air requirements for all our mixes has shown to produce improved concrete. New Mexico We require that a mix be tested in the laboratory for performance properties before being allowed for use on actual projects. Properties tested for include air content, durability, permeability, shrinkage, and optimization of aggregate structure. We also require that batch weights and plastic properties be properly documented before allowing the fresh concrete to actually be placed. New York CIP HPC was established in 1996. We developed a prescriptive mixture requirement that shows the potential for reduced cracking and typically a 50% reduction in permeability in the field. At the same time we went to a 14-day wet curing process to further hydrate the HPC. Placement/vibration requirements were also enhanced at that time. North Carolina The substitution of silica fume and corrosion inhibitors for a portion of the portland cement Ohio The standard specification calls for No. 8 coarse aggregate, 660 lb of total cementitious materials (cement, slag cement or fly ash, and silica fume) and 0.40 w/c ratio. Due to cracking experienced with this mix, some districts have adopted revised design by plan notes that require a combination of No. 57 and No. 8 aggregates, 600 lb of total cementitious materials and 0.43 w/c ratio. One district has excluded the use of coarse aggregate with absorptions less than 1.0% in their bridge decks. They have experienced fewer problems with cracking from these mixes. Presumably from a combination of better grading, less shrinkage from cement, less autogenous shrinkage, and some internal curing from the higher absorption aggregates. These were all introduced at the same time, so how much improvement is attributed to what change has not been determined. Oklahoma Use of SCC Oregon We have changed curing requirements to require covering the concrete within 20 ft and 20 minutes of the last pass of the screed. We occasionally use polypropylene fibers to reduce cracking. This has generally been successful, but at a cost premium. We are doing research on precast deck panels which we anticipate will eliminate cracking and improve abrasion resistance. We are doing research on shrinkage reducing admixtures and lightweight fine aggregate to reduce shrinkage and potentially reduce curing time.

53 Pennsylvania Some key aspects to improved performance are: 1. Limiting rate of strength gain, keeping 28-day/7-day strength to 1.20 maximum 2. Reducing the amount of cementitious material and paste content during mix design approval 3. Improved curing practices consistent with ACI, including mandatory 14-day wet cure 4. Evaporation rate controls per ACI-305R-99, Fig 2.1.5 5. Preclude pumping of concrete South Carolina Using supplementary cementitious materials such as fly ash and silica fume, and using a corrosion inhibitor South Dakota The addition of fly ash has been an improvement. Tennessee Maximum limit on chloride ion penetrability as per AASHTO of 1500 coulombs Texas Give multiple options to provide HPC Utah We developed a specification for self-consolidating concrete. Virginia Require SCM for ASR resistance, permeability testing with accelerated curing Wisconsin 14-day wet cure, reduced cement content, reduced w/c ratio What specifications and practices has your agency used that were unsuccessful? What is the basis for this assessment? Agency Unsuccessful Specifications and Practices Basis Alaska Although the permeability is improved, the workability of concrete deck overlays with HPC is decreased. HPC in deck overlays often has a cracked appearance during construction. Florida Our Section 353 is used for slab replacement concrete. This concrete is prone to cracking since the concrete must develop high early strength (2,200 psi in 6 hours or less). This is not really considered HPC but it is required to perform under some extenuating circumstances. The mix for the slab replacement concrete has a high cementitious content to ensure the required strength at opening to traffic. These mixes are very susceptible to early age cracking due to excessive stresses in the concrete at opening to traffic. Normally we get the required strength based on cylinder breaks or maturity but cracking still occurs. Illinois Concrete may be too strong for bridge decks, which may be causing cracks. Field observations Maine Surface tolerance and finish An acceptable finish can be subjective at times. Massachusetts Silica fume alone Workability issues from field, cracking reported in new decks Michigan Shrinkage reducing admixture Laboratory mixes were successful, but during field trials we could not maintain the specified entrained air content. Construction was halted and conventional concrete was used to complete the project. Minnesota Have had limited success with high fly ash (> 30% Type F) bridge deck mixes. Field surveys Nevada We have implemented shrinkage reducing admixture into deck concrete that is placed on steel girders in order to reduce cracking. This has helped, but not to a satisfactory degree. Observation 8.

54 New Hampshire We originally had no lower limit on our permeability specification and the contractors were getting numbers below 800 coulombs by adding cement to get the bonus. We adjusted the specification and increased the lower limit. The added cement to lower the permeability number was creating more cracks and a brittle deck. It also created work issues. New Jersey 14-day wet cure of decks, some deck cracking — New Mexico Since the actual air content is so important to know, we used to require that the air content be measured for compliance of the theoretical maximum unit weight, and corroborated with the pressure pot. However, we had great difficulty in getting our inspectors to do both tests, and they were recording pressure pot results without actually performing the test. We have now eliminated the pressure pot tests and use only the air determined from the theoretical maximum unit weight. Experience New York Nothing specific that has resulted in any design changes or specification revisions We continue to see transverse cracking on many decks although the cracks are fewer and finer. Autogenous shrinkage has been a concern that has led to the consideration of internal curing with HPC. Ohio The standard HPC specification can obviously be improved upon. The designs by plan note are performing better as far as cracking is concerned. They are not getting as high strength as the standard, but still well above the design strength. Oklahoma Use of silica fume Visual Oregon Initial use of high performance concrete with an evaporation reducer placed immediately following the last pass of the screed was not successful. Excessive cracking using this procedure resulted in the 20 feet and 20 minute requirement mentioned above. — Pennsylvania 1. Supplied concrete that had a rapid strength gain, focusing too much on maintaining the construction schedule 2. Potentially by not enforcing the maximum slump limits when pumping concrete Assessment is primarily based on feedback from field personnel, and the concrete deck performance outcome as to deck cracking. South Dakota The use of silica fume was not successful for us. The concrete with silica fume was difficult to work with (decreased workability) and resulted in increased cracking. Texas Requiring air entrainment in all concrete combined with HPC. Have since been more selective on where air entrainment is required Problems in the field. We ended up with concrete with excessive amounts of air in the hardened concrete as a result of contractor overdosing and testing equipment unable to adequately measure air content correctly in fresh concrete. Washington HPC specifications requiring fly ash for bridge decks Increased cracking

55 Agency Response Alabama One requirement in our Special Provision for this project was that the contractor would be required to perform a test pour of the HPC. We did not specify the conditions under which the test pour should be performed. As a result, the test pour was performed during the summer in extremely hot temperatures, while the actual girder pours were made in winter months when the temperature was much cooler. The concrete struggled to meet the strength requirement during the production pours, as evident by the fact that 8 out of 18 pours failed to meet the 28-day strength requirement at the time. See attached Research Project reports from Auburn University, done in conjunction with ALDOT (Stallings and Eskildsen 2001 and Stallings and Porter 2002). Alaska Cast-in-place HPC may need to focus more on workability—not just the engineering properties. Arizona See Jaber 2007. Florida We know from data collected during the last 30 years that Class F fly ash is a necessity to ensure durable concrete. We have combined the use of the fly ash with low w/c ratios (0.38 to 0.41) and have developed a defense mechanism that has protected our structures from chlorides and sulfates. We have a few structures that are in need of some rehabilitation, but for the most part our structures are in exceptional condition. Georgia We have learned that we can use HPC for our prestressed concrete beams and piling. Idaho Location can have a significant impact. Less sophisticated suppliers, geometry of the deck, etc., can be major influences. Kansas Potential issues with low cement content and angular aggregates. University of Kansas, LC-HPC Study. Binary mixes are not as effective for reduction of permeability as ternary mixes. US-59 project, the report is being prepared at this time. Louisiana See LTRC Reports on HPC (2008) and long-term monitoring of the HPC Charenton Canal Bridge (Bruce et al. 2009). Maryland Placement techniques had to be slightly modified to account for the consistency of the mix that required the use of fibers. Michigan Prices for HPC will not necessarily be much in excess of the cost of a conventional concrete. A variety of plants have been able to successfully batch our HPC. Minnesota Work closely with industry, may require many field trials Nebraska Require higher degree of QC and timing when the ingredients go into the mixer Nevada The prewetted or very moist burlap covers must be placed within 20 to 30 minutes after final finish with high pressure fogging between the hand finishers and the burlap crew. The burlap must remain soaked until the hoses and covers are placed. New Hampshire Again, we use QC/QA specifications that were developed with a committee made up of DOT, concrete suppliers, and contractors. This aided in the implementation process because all had a say in the development. New Mexico HPC can be very effective, but it must be completely and thoroughly thought out, and implemented at the project level. Laboratory tests need to stay in the laboratory and field tests need to be used to corroborate the consistency of the mix that was measured in the laboratory. New York After a few years of use, the effectiveness of HPC to reduce cracking was questioned. A research study was progressed—Technical Report 03-01 (Graves 2003). Oklahoma We have been successful in making high strength concrete. Oregon Continuous fogging and curing in place as soon as practical is essential. Pennsylvania See attached files (Taylor et al. 2010 and PACA undated). What lessons has your agency learned about the implementation of HPC? Specific case studies would be useful for the synthesis. Please list any reports or attach files in Question 35. 9.

56 South Carolina HPC mix was hard to handle in the field. The mix was very rich and sticky and needed experienced contractors. South Dakota Inclusion of fly ash in the mix decreased permeability and increased workability with little or no other effect to the concrete Tennessee Research shows our standard mix meets most HPC criteria. Texas With time, HPC became the normal concrete in most urban locations. However, we still have rural areas of the state where we cannot get SCM’s and concrete producers don’t care to provide us concrete containing them. It turns out you cannot force the issue. Virginia HPC requires attention to mixture proportioning and construction practices. End result specifications are effective in achieving quality product. Washington Move to performance specifications for bridge decks 3. CAST-IN-PLACE CONCRETE 10. Has your agency implemented high performance concrete in cast-in-place bridge decks? Yes: 31 agencies No: 8 agencies If no, why not? Agency Reason Alaska Have used HPC for deck overlays with some mixed results and we don’t do many cast-in-place decks. California We do not call it HPC. We address it prescriptively. Georgia It is not needed for Georgia DOT bridge decks. Idaho We did one project with a cast-in-place high performance concrete deck (half a bridge was regular concrete and the other half high performance concrete). There was no noticeable difference between the two decks. It should be noted the geometry of the deck almost assured cracking. Nebraska Only on deck overlays, where we use silica fume Oklahoma It appears that the improved curing process has improved the durability of our decks. The additional expense for the HPC decks does not appear to be justified at this time. Utah Material availability. Understanding of cost/benefit. Awareness. Resources required to control quality Wyoming Our standard concrete, epoxy-coated reinforcement, and 8 in. thick decks are performing well. After completing this question, go to Section 4. 11. In your agency’s performance specifications, which of the following characteristics are currently specified for cast-in- place concrete bridge decks? Check all that apply. Not applicable: 11 agencies Permeability: 15 agencies Freeze-thaw resistance: 8 agencies Deicer scaling: 3 agencies Abrasion resistance: 2 agencies Workability: 11 agencies ASR resistance: 9 agencies Sulfate resistance: 3 agencies

57 Compressive strength: 23 agencies Modulus of elasticity: 2 agencies Creep: 1 agency Shrinkage: 6 agencies Other: 8 agencies Other characteristics included restrained shrinkage cracking, surface resistivity, air content, corrosion resistance, w/c ratio, and strength gain such that the 7-day compressive strength can be no greater than 80% of the 28-day strength, and the 56-day compressive strength must be at least 108% of the 28-day compressive strength. In your agency’s prescriptive specifications, which of the following characteristics are currently considered in developing the specifications for cast-in-place concrete bridge decks? Check all that apply. Not applicable: 3 agencies Permeability: 24 agencies Freeze-thaw resistance: 16 agencies Deicer scaling: 4 agencies Abrasion resistance: 4 agencies Workability: 19 agencies ASR resistance: 18 agencies Sulfate resistance: 7 agencies Compressive strength: 29 agencies Modulus of elasticity: 4 agencies Creep: 2 agencies Shrinkage: 9 agencies Other: 6 agencies Other characteristics included surface resistivity such as 29 kohm-cm at 28 days, corrosion resistance, air content, admixtures, reduced “overdesign” strength, reduced maximum cementitious content, 14-day wet cure, and restrained shrinkage cracking. What strategies does your agency currently use to minimize cracking in cast-in-place concrete bridge decks? Strategy to Minimize Bridge Deck Cracking No. of Agencies Yes No None 0 11 Specify minimum cementitious materials content 26 8 Specify maximum cementitious materials content 19 16 Specify minimum concrete compressive strength 33 2 Specify maximum concrete compressive strength 4 27 Specify a ratio between 7- and 28-day compressive strength 5 27 Specify minimum concrete temperature at placement 30 6 Specify maximum concrete temperature at placement 32 2 Specify maximum concrete temperature during curing 9 21 Specify maximum water-cementitious materials ratio 34 2 Specify maximum slump 30 5 Specify maximum water content 14 19 Require use of the ACI surface evaporation nomograph 18 15 Require wind breaks during concrete placement 13 21 Require evaporation retardants 9 23 12. 13.

58 Require fogging during placement when evaporation rates are high 27 8 Other 12 5 If other, please list. Agency Other Strategies Alabama Note: wind breaks are only required when evaporation rate is too high. Arizona Fast track finishing technique, minimum surface manipulation, concrete surface protection, immediate wet curing after surface cover is applied Colorado Only allow Type A & dual rated A/F admixtures, require a minimum 20% pozzolan, require the use of 55% size 57, 6 or 67 coarse aggregate as a percentage of total aggregate, minimum w/cm ratio, all mix water must be added at batching, and no slump adjustments with water, but with admixtures Florida We require the contractor to have a portable weather station on site when concrete is being placed. This tells the inspector and the contractor when wind speeds have been exceeded and protection needs to be in place. It also informs the contractor when the temperature is too high and that he needs to fog the concrete or protect the concrete from rapid moisture loss by one of the approved methods. Iowa Require evaporation retardants—allow as needed, but not for finishing. Other—Wet burlap cure within 10 minutes of final finishing. Continuously wet for 7 days and maintain greater than or equal to 50 F for 7 days. Louisiana For mass concrete, specify maximum concrete temperature during curing. Maryland Require wet curing Michigan Use of evaporation nomograph, nighttime concrete placements, 7-day wet cure Nevada Wet burlap placement within 30 minutes New Hampshire The contractor has to submit a plan before a deck placement. Evaporation and curing must be addressed in the plan. New Mexico Windbreaks and evaporation retarders are allowed if evaporation potential is too high. New York Being prescriptive, the specification does not address some of the expected benefits or controls that went into the specification development for HPC. The specification does restrict w/c ratio, cementitious content, and environmental controls. Newer special specifications are looking to address some of the other concerns like rate of strength gain and ratio of 7 to 28 day strengths as well as mix temperature. Additionally, use of internal curing is being experimented with. Ohio 7-day wet cure followed by curing compound Oregon In some cases, we may specify polypropylene fibers in the mix. South Dakota Require 20% fly ash in the cementitious materials and a minimum 7-day wet cure Texas Wet curing Virginia Specify minimum cementitious materials content—in ERS minimum cementitious content is not required. Wisconsin Limit hand finishing, 14-day wet cure, place wet burlap within 10 minutes of finishing What strategies to minimize cracking in cast-in-place concrete bridge decks have been most effective?

59 Agency Most Effective Strategies to Minimize Concrete Deck Cracking Alabama Use of nomographs, wind breaks, and fogging Arizona Good curing plan and good protection plan as in other above California Curing Colorado Wet curing District of Columbia Reduction of total cement Florida Effective and adequate curing in a timely manner is the best means of minimizing cracking. Georgia Proper curing and controlling the concrete temperature Hawaii Use of shrinkage-reducing admixture Iowa Early wet cure, reduction in portland cement content, evaporation rate control, limit on maximum concrete temperature at time of placement Kansas Fogging, 14-day wet cure, SCMs, reduced cement and water content Louisiana Prompt and proper construction methods Maine Extra steel in areas subject to movement, minimize delays in applying wet curing Maryland Wet curing and fibers Massachusetts Wet curing Michigan Nighttime concrete placements, 7-day wet cure Minnesota University of Kansas mix designs, limited cement content, shrinkage testing, performance-based specifications based on meetings with industry Nebraska Increased the curing from 5 days to 7 days Nevada Wet curing New Hampshire Placing wet burlap on the deck as soon as possible after placement and keeping it wet for 7 days New Mexico Mix modifications to minimize characteristic shrinkage potential, controlling batch weights and water, proper curing New York Maintaining reasonable w/c and water content controls appear to impact performance. Internal curing is showing promise but still too early to know for certain. North Carolina The limit on maximum temperature and prescriptive requirements for the curing of the deck Ohio Wet curing, using mix designs with well-graded aggregates has also helped. Oregon Reducing time between concrete placement and application of wet cure Pennsylvania No pumping, reduced paste content, 14-day wet cure, slow strength gain via 28-day/7-day ratio South Carolina Require wind breaks during concrete placement, require fogging during placement when evaporation rates are high Texas Temperature controls

60 Utah Proper curing and placing sequence Wisconsin Limiting cement content, wet cure What strategies to minimize cracking in cast-in-place concrete bridge decks have been least effective? Agency Least Effective Strategies to Minimize Concrete Deck Cracking Alabama Maximum slump Colorado Prescriptive mix designs Florida Normally the contractor wants to wait until he gets the entire deck concrete placed before he starts to cure the concrete. This is usually too late to prevent crack initiation. With that, we have a requirement for the curing to start as soon as the initial sheen is gone from the concrete. As soon as the bleed water is gone from the concrete surface the contractor is required to implement one of the approved methods of curing. Kansas Maximum and minimum temperature control Louisiana Improper construction methods Massachusetts Curing membranes Minnesota High cement contents, high compressive strength requirements Nevada Evaporative retarders and curing compound New Hampshire Monitoring evaporation before and during placement. This is a required procedure by contractors and must be addressed in their plan. New York Controlling construction practices has been difficult as the focus is often on getting the work done— not necessarily getting the work done correctly. That is not a specification issue but one of enforcement that needs to be corrected. Pennsylvania Poor QC, not requiring a test slab to ensure workability Texas Maximum w/c ratio and minimum compressive strength Virginia Rich mixtures and low water-cementitious materials ratio Washington Evaporation retardants 14. What is the frequency of use of the following supplementary cementitious materials in your agency’s cast-in-place concrete bridge decks? Supplementary Cementitious Material Extent of Use as a Percentage of All Bridge Decks None 1 to 33 34 to 67 68 to 100 Fly ash Class C 17 8 3 5 Fly ash Class F 2 17 5 11 Pozzolan Class N 27 3 0 1 Silica fume 11 16 1 7

61 Ground-granulated blast- furnace slag 10 12 6 7 Other 9 0 0 0 No other supplementary cementitious materials were listed. What is the frequency of use of the following admixtures for cast-in-place concrete bridge decks? Admixture Extent of Use as a Percentage of All Bridge Decks None 1 to 33 34 to 67 68 to 100 AASHTO M 194 Type A— Water-reducing admixtures 4 4 5 22 AASHTO M 194 Type B—Retarding admixtures 9 11 7 7 AASHTO M 194 Type C—Accelerating admixtures 23 8 2 2 AASHTO M 194 Type D—Water-reducing and retarding admixtures 11 11 5 6 AASHTO M 194 Type E—Water-reducing and accelerating admixtures 23 8 1 0 AASHTO M 194 Type F—High range water-reducing admixtures 10 8 7 10 AASHTO M 194 Type G—High range water-reducing and retarding admixtures 16 11 2 3 Corrosion inhibitors 20 9 0 4 Shrinkage reducing admixtures 25 5 0 1 Expansive components 27 4 0 0 What length of wet curing does your agency currently specify for cast-in-place concrete bridge decks? None 3 days 7 days 14 days Other Check only one 0 1 23 9 4 Other lengths of wet curing were 5, 8, and 10 days. What practices or tests, if any, does your agency currently use for acceptance of a new HPC mixture for concrete bridge decks? Agency Practices or Tests Used for Acceptance of New HPC Mixtures for Concrete Bridge Decks Alabama AASHTO T 22, ACI 211.4R, AASHTO T 119, AASHTO T 152, AASHTO T 309, 3-point curve of w/c ratios vs. compressive strength, AASHTO T 27 Arizona Trial batches and pre-qualification of HPC mixes according to Special Provision for accepting HPC deck Colorado Each project must construct a test deck the width of the largest pour and a minimum of 30 ft long and at least the depth of the deck. It shall have the same reinforcement as the deck. This is to demonstrate that the concrete will consolidate properly and allow the contractor's crew to practice placing, finishing, and curing the HPC. District of Columbia Slump, air content, unit weight of plastic concrete, permeability, and compressive strength Florida Mixes are trial batched for initial approval. They are required to meet the minimum compressive strength and in most cases the concrete is trial batched under hot weather concrete conditions. It must maintain the allowable slump called for by the class of mix at greater than 90 degrees for 90 minutes. If the slump falls below the minimum for the class or application, the mix is rejected. 15. 16. 17.

62 Illinois Slump, air content, and strength Iowa Trial batch strength and permeability Kansas Approval of the mix by testing permeability using permeable voids or rapid chloride permeability and ACI statistical strength analysis Louisiana Trial batch Maine Permeability trial batch for new concrete plants or new mix from existing plants Maryland Trial batch Massachusetts Trial batch testing (temperature, air, slump) 28-day compressive strength Michigan Must meet specification requirements for material content/proportioning, coarseness and workability factors, and compressive strength Minnesota Laboratory testing of those properties indicated in Question No. 11 and a full-scale field test placement Nevada ASTM C1202 Rapid Chloride Permeability, AASHTO T 303 Mortar Bar Expansion, Modulus of Elasticity, California Method for Creep when required, and shrinkage by the California Method New Hampshire Test results for air, strength, permeability, ASR on the aggregates, w/c ratio must be submitted with the mix. New Jersey Verification testing on new mix design New Mexico Comprehensive tests performed at an approved testing laboratory for compressive strength, hardened air content, ASR mitigation, maximum shrinkage potential, permeability, durability, and rate of strength gain New York An in-house evaluation where we are concerned with shrinkage cracking, scaling and freeze-thaw durability, and reduced permeability North Carolina The mix design is reviewed for compliance with the project specifications and special provisions. The Materials & Testing Laboratory performs standard tests. Ohio Slump and air content in the field. HPC strength is tested, but not necessarily as an acceptance tool. Oregon Compressive strength per AASHTO T 23, temperature, air content, slump, water-cementitious materials ratio, density, and yield Pennsylvania Permeability, compressive strength, air content, heat of hydration, chloride ion, scaling, ASR, freeze- thaw durability, abrasion resistivity, and shrinkage South Carolina Compressive strength South Dakota Slump, air, 28-day strength, and water/cement ratio Tennessee AASHTO T 277 Utah Trial batch is submitted to the materials laboratory for evaluation. It must meet or exceed parameters of conventional concrete. Virginia Trial batch Wisconsin A laboratory trial mix must be produced as well as a trial mix from each plant used to supply the project. All mixes must be tested at a department qualified laboratory, with the following tests: AASHTO T 119 for slump, AASHTO T 121 for density, AASHTO T 152 for air content, AASHTO T 22 for compressive strength, AASHTO T 277 for rapid chloride permeability, and AASHTO T 309 for temperature, and water-cement ratio.

63 Does your agency conduct tests of the hardened cast-in-place concrete to check end-product performance other than compressive strength? Routinely: 5 agencies Sometimes: 12 agencies Never: 20 agencies If routinely or sometimes, what tests are performed? Agency Tests Performed to Check End Product Performance Arizona Rapid chloride permeability, chloride ion content in bridge deck profile Florida When there is a issue with low strength, we require the contractor to remove cores. We’ll use two cores to verify the strength then one or two cores to verify resistivity of the concrete. In some cases if the strength is very low and there is a question as to whether the concrete will stay in place, we may test the concrete for chlorides as well as surface resistivity to ensure that we have a durable concrete in place. Iowa Permeability (rarely) Kansas If there is a reason to question the quality of the in place concrete cores may be taken for hardened air content and permeability. Louisiana Permeability—surface resistivity Maine For permeability if acceptance tests are disputed Massachusetts Soundness and cores Minnesota Hardened air content, permeability Nevada Permeability New York When we originally developed HPC we did perform field testing for strength, permeability, absorption, unit weight, and freeze-thaw from field samples. We observed consistent performance and thus stopped any testing after 2 years. North Carolina Chloride permeability Ohio Initially we had rapid chloride permeability tests (AASHTO T 277), drying shrinkage (ASTM C157),and heat of hydration testing performed to evaluate the designs. That was discontinued after a short time. Pennsylvania Document amount of deck cracking by observation South Dakota Petrographic analysis of cores Texas Only if there are problems Virginia Permeability Wisconsin Chloride penetration resistance—AASHTO T 259, T 277 What are your agency’s current practices to evaluate short- and long-term performance of HPC in bridge decks? Agency Current Practice to Evaluate Performance of HPC in Bridge Decks Alabama Testing slump, air, and compressive strength of the concrete at the first load delivered, then once every 50 yd3 Alaska Monitor deck condition as part of bridge inspection program 18. 19.

64 Arizona Monitoring HPC report, see Jaber 2007. California Monitor Maintenance Reports Colorado None, other than the required routine bridge deck inspections District of Columbia None at this time except rapid chloride permeability and compressive strength Florida Our bridge inspectors assess our non-movable bridges every 2 years and the movable ones every year. They have been trained to look for areas of corrosion or severe cracking and spalling. When this is reported to the Corrosion Section Field Operations, they investigate the structure in more detail. They may take resistance measurements, or remove cores to verify chloride content and take chloride profiles. Illinois Field observations Kansas Air content of concrete sampled at placement, permeability of concrete sampled at placement, and strength of concrete sampled at placement Louisiana Visual inspection Maryland Visual inspections every 2 years, major waterway bridges are visually inspected yearly. Michigan Periodic site visits to evaluate deck condition, including cracking, scaling, overall condition Minnesota In-service bridge inspections, occasional special inspections Nevada The Structural Division inspects bridges every 2 years New Mexico Monitoring through a pavement management program North Carolina The deck and all other components of the bridge are inspected every 2 years. Oregon Visual inspection following construction and during required two-year routine inspections Pennsylvania Implemented a deck performance database to track amount of deck cracking and actual deck rating over time South Dakota The only formal evaluation are [of] those decks involved in research projects. Texas Decks are walked to check for cracking but not much else. Virginia Visual inspection and sometimes coring and testing 4. PRECAST, PRESTRESSED CONCRETE Has your agency implemented high performance concrete in precast, prestressed concrete components? Yes: 21 agencies No: 16 agencies 20. Agency Reasons for Not Using HPC in Precast, Prestressed Concrete Arizona Unfamiliar with practice California We do not call it HPC—we require SCMs (in some cases). Colorado We allow the suppliers to use whatever concrete they see fit. We do not approve their concrete mixtures. Some use SCC.

65 Idaho Haven’t seen the advantage in doing so Illinois Illinois DOT has not seen a compelling reason to have low permeability concrete beams. Kansas Due to the low water-cement ratios and controlled environment of the precast plants we have not been as involved. KDOT does however allow the use of the same SCMs and require permeability testing of the precast concrete. Aggregates are KDOT approved materials to prevent ASR and freeze-thaw damage. Maryland Our definition of HPC based on a lower compressive strength does not lend itself to precast/prestressed elements. Ohio There are permeability requirements for prestressed concrete, but that’s not necessarily high performance. For precast and prestressed concrete, the producers use their own designs. Oregon We have used high performance concrete in selected applications, but not for typical applications. We have had excellent long-term performance with precast concrete girders without using a high performance concrete. We typically get 10,000 + psi concrete strength with existing mix designs. Our precasters are comfortable achieving these strengths, but are not confident they can achieve significantly higher strengths with the aggregates they have available. Pennsylvania Precast components use high-early strength concrete due to plant production schedules. Tennessee No specific definition of HPC Utah Supplier ability, awareness, etc. Wisconsin Have not had a need After completing this question, go to Section 5. In your agency’s performance specifications, which of the following characteristics are currently specified for precast, prestressed concrete beams and deck panels? Check all that apply. Characteristic Precast Beams Precast Panels Not applicable 10 14 Permeability 7 5 Freeze-thaw resistance 8 8 Deicer scaling 2 3 Abrasion resistance 2 4 Workability 6 3 ASR resistance 8 9 Sulfate resistance 0 2 Compressive strength > 6.0 ksi 17 8 Modulus of elasticity 5 5 Creep 2 3 Shrinkage 2 3 Other 0 0 21.

66 Characteristic Precast Beams Precast Panels Not applicable 7 13 Permeability 11 3 Freeze-thaw resistance 11 8 Deicer scaling 2 2 Abrasion resistance 1 1 Workability 11 2 ASR resistance 10 6 Sulfate resistance 4 4 Compressive strength > 6.0 ksi 19 4 Modulus of elasticity 3 2 Creep 2 2 Shrinkage 4 3 Other 2 1 The one other characteristic was flexural strength. What is the frequency of use of the following supplementary cementitious materials in your agency’s precast, prestressed concrete beams? Supplementary Cementitious Material Extent of Use as a Percentage of All Bridges None 1 to 33 34 to 67 68 to 100 Fly ash Class C 24 2 1 3 Fly ash Class F 10 11 2 6 Pozzolan Class N 23 4 0 1 Silica fume 14 10 2 2 Ground-granulated blast-furnace slag 16 5 3 3 Other 13 0 0 1 The other material was Type IP cement. What is the frequency of use of the following supplementary cementitious materials in your agency’s precast, prestressed concrete deck panels? Supplementary Cementitious Material Extent of Use as a Percentage of All Bridges None 1 to 33 34 to 67 68 to 100 Fly ash Class C 22 2 1 1 Fly ash Class F 12 6 3 4 Pozzolan Class N 22 3 0 0 Silica fume 16 6 1 1 In your agency’s prescriptive specifications, which of the following characteristics are currently considered in developing the specifications for precast, prestressed concrete beams and deck panels? Check all that apply. 23. 22. 24.

67 Ground-granulated blast- furnace slag 18 3 3 1 Other 14 0 0 0 What is the frequency of use of the following admixtures for precast, prestressed concrete bridge beams? Admixture Extent of Use as a Percentage of All Bridges None 1 to 33 34 to 67 68 to 100 AASHTO M 194 Type A—Water-reducing admixtures 8 6 5 8 AASHTO M 194 Type B—Retarding admixtures 14 5 5 1 AASHTO M 194 Type C—Accelerating admixtures 18 3 4 0 AASHTO M 194 Type D—Water-reducing and retarding admixtures 12 7 4 2 AASHTO M 194 Type E—Water-reducing and accelerating admixtures 18 4 2 1 AASHTO M 194 Type F—High range water-reducing admixtures 3 3 7 15 AASHTO M 194 Type G—High range water-reducing and retarding admixtures 14 5 3 4 Corrosion inhibitors 14 7 2 4 Shrinkage reducing admixtures 20 4 0 1 Expansive components 24 0 0 0 What is the frequency of use of the following admixtures for precast, prestressed concrete deck panels? Admixture Extent of Use as a Percentage of All Bridge Decks None 1 to 33 34 to 67 68 to 100 AASHTO M 194 Type A—Water-reducing admixtures 9 5 4 6 AASHTO M 194 Type B—Retarding admixtures 14 5 4 0 AASHTO M 194 Type C—Accelerating admixtures 15 3 4 0 AASHTO M 194 Type D—Water-reducing and retarding admixtures 13 6 4 0 AASHTO M 194 Type E—Water-reducing and accelerating admixtures 15 4 2 1 AASHTO M 194 Type F—High range water-reducing admixtures 9 2 4 8 AASHTO M 194 Type G—High range water-reducing and retarding admixtures 16 4 1 2 Corrosion inhibitors 14 4 2 3 Shrinkage reducing admixtures 19 3 0 0 Expansive components 20 0 0 0 25. 26.

68 Agency Curing Method Alabama Either wet cure for a minimum of 3 days, or steam cure for minimum of 24 hrs. This is all prior to detensioning. Alaska Although several methods are permitted, most all girders are steam cured. Florida The curing for these elements is 72 hours of wet curing. If the forms are released or removed, the curing process must be continued to meet the full duration of the 72 h. Hawaii Wet curing or water curing Maine Wet cured until design strength is achieved Massachusetts Steam/wet cure until 4000 psi is achieved Michigan Temperature range of 70°F to 160°F. Only apply steam or radiant heat after initial set. Maximum ambient and concrete temperatures are specified, as well as maximum cooling rate. Minnesota None, we only require curing until 45% of design strength and detensioning strength is always higher than that. Nevada Steam curing and curing compound method, radiant heat curing has been included on recent projects. New Hampshire Curing is allowed to be stopped when the member reaches release strength. New Mexico They are checked for minimum strength for release and transportation purposes. New York Unless steam curing is complete, all elements must be cured for 7 days. If removed from forms wet burlap/plastic covers used as we further require application of penetrating sealers and curing compounds would have to be removed. Oregon Members are cured using low-pressure steam or radiant heat inside an enclosure. South Dakota Low pressure steam, radiant heat, or as specified for CIP structural concrete Texas 4 days wet cure required for piling and top surfaces of direct traffic beams (i.e., box and slab beams) Utah Panels are wet cured for 14 days. Nothing for beams after they are removed from the bed. Virginia Steam curing or wet curing Washington Both steam and radiant curing methods are used. What practices or tests, if any, does your agency currently use for acceptance of a new HPC mixture for precast, prestressed concrete components? Agency Practices or Tests Used for Acceptance of New HPC Mixtures for Precast, Prestressed Concrete Components Alabama Same as for cast-in-place Alaska Strength tests Colorado Just strength What curing, if any, of precast, prestressed components is currently specified after they are removed from the casting bed?27. 28.

69 Georgia Strength data, permeability data, concrete test data (slump, air entrainment, temperature, etc.) Hawaii Same tests as non-HPC mixtures Iowa Strength and permeability Louisiana Trial batch Maine Mix design review Massachusetts Air, slump, temperature, finish/color, compressive strength Michigan Compressive strength Minnesota Compressive strength Nebraska Trial batches Nevada Same as deck concrete New Hampshire Test results for strength, permeability, air, and slump/spread on the mix, and ASR on the aggregates/mix New Jersey Verification testing of new mix design New Mexico Same as cast-in-place concrete except we do not require a controlled strength gain curve due to nature of precasting operations. New York Mixture prequalification is required. Other testing during production is done for acceptance. See specification 718-06 at https://www.dot.ny.gov/main/business-center/engineering/specifications/ english-spec-repository/section700.pdf North Carolina The mix design is reviewed for compliance with the project specifications and special provisions. The Materials & Tests Laboratory performs standard tests. Oklahoma Compressive strength and visual inspection Oregon Use of HPC in prestressed concrete components is rare. When used, testing is similar to non-HPC mixes. South Dakota Slump, air, strength, and water/cement ratio Utah Trial batch is submitted to the materials lab for evaluation. It must meet or exceed parameters of conventional concrete. Virginia Trial mixture Does your agency conduct tests of the hardened precast, prestressed concrete to check end-product performance other than compressive strength? Routinely: 4 agencies Sometimes: 7 agencies Never: 16 agencies 29. Florida All of our mixes are trial batched and verified by the district inspectors. This may change as the department looks at ways to economize their processes. There is a major push for performance specifications in an effort to minimize department interaction with the contractor. The thinking is that we tell the contractor what we want for a finished product, he delivers it, and we verify it. If it meets the requirements of the plans, he gets paid; if it does not, we go to resolution.

70 Iowa Permeability Louisiana Surface resistivity Maine Verification of permeability if applicable (very rare) Nebraska Modulus of elasticity New Hampshire Permeability New Mexico Plastic properties and compressive strength tests New York Acceptance testing performed per the PCCM found at https://www.dot.ny.gov/divisions/engineering/structures/manuals/pccm North Carolina Permeability Virginia Permeability 30. What are your agency’s current practices to evaluate short- and long-term performance of HPC in precast, prestressed components? Agency Current Practices to Evaluate Performance of HPC in Precast, Prestressed Concrete Components Alabama Same as for cast-in-place. Alaska Examine condition of the girders as part of the bridge inspection program Florida Our bridges are inspected every 2 years, and any defect concerning a question of the durability of the concrete will be evaluated further by a representative of the Corrosion Section, or by the Structural Materials Section. If repairs are required then one of our consultants would be brought in to perform the work. Minnesota In-service inspections Nebraska Monitor fresh concrete characteristics, and testing at release, 7, 28, and 56 days New Mexico Pavement management program North Carolina The precast, prestressed girders and all other components of the bridge are inspected every 2 years. Oklahoma Visual inspection (NBIS) Oregon Routine bridge inspections every 2 years according to federal standards South Dakota Only those components involved in research projects are formally evaluated. Texas Visual Virginia Visual inspection If routinely or sometimes, what tests are performed? Agency Tests Performed Florida If there is a question as to the strength of the concrete, cores may be removed to verify in-place strength, or surface resistivity may be performed to validate durability. Georgia Permeability is checked.

71 Florida We are investigating the use of a field device that can perform several NDT evaluations in one pass. We have a prototype that can be attached to the side of a prestressed girder. The scanning device initiates at a starting point and evaluates the concrete at any interval not to exceed 5 square feet. For instance, we could evaluate every square inch of a 5 foot square area without any outside influence using pulse velocity, acoustic emission (echo impact), and radar at the same time in one pass. Illinois Illinois DOT is currently working on a report to assess the performance of HPC bridge decks constructed between 2000 and 2003. Iowa Shrinkage Kansas High Performance Low Cracking Concrete, University of Kansas. Effects of Temperature and Curing on Concrete with SCMs, KDOT. Louisiana LTRC: 03-7ST, 10-3TIRE, 09-4C, 09-6C, 09-5C, 10-1C. Michigan Precast bridge systems: http://rip.trb.org/browse/dproject.asp?n=27330 Causes and Solution Strategies for Deck Cracking: http://rip.trb.org/browse/dproject.asp?n=27311 Effects of Debonded Strands in Prestressed Beams: http://rip.trb.org/browse/dproject.asp?n=27303 Rapid Deck Replacement, Precast Panels: http://rip.trb.org/browse/dproject.asp?n=27302 University of Kansas Pooled Fund Project for Construction of Crack-Free Bridge Decks, Including Development of LC-HPC (Low Cracking High Performance Concrete). Minnesota Bridge deck cracking surveys, participating in University of Kansas study, trial projects with HPC for deck placements and precast substructures. Will build our first full-depth precast deck panels this summer Nevada We are looking at air entrainment of in-place concrete relative to sampling at the mixer versus sampling at the end of the pump truck hose. New Hampshire Our research program includes a project to establish upper limits for supplementary cementitious materials (fly ash and slag cement) for durable concrete. However, the project has not begun. New York Internal curing of HPC experimentation progressing to see if there is a reduction in deck cracking Oregon Shrinkage Limits and Testing Protocols for High Performance Concrete at Oregon State University. Self-Curing Concrete at National Chiag-Tung University, Taiwan. Internal Curing of Concrete Bridge Decks (using lightweight fine aggregate) at Oregon State University. Abrasion-Resistant Concrete Mix Designs for Bridge Decks at Oregon State University Pennsylvania On-going “Bridge Deck Cracking Prevention and Remediation” research project, to document deck cracking rates and to develop “best practices” regarding engineering design, mix design, and construction methods, to produce the highest quality bridge decks South Dakota SD2005-11 Evaluation of Crack Free Bridge Decks and TPF5(051) Construction of Crack Free Bridge Decks Tennessee Tennessee Tech: Low Permeability Mix Development and Low Heat of Hydration. UT: Surface Resistivity Correlation to Rapid Chloride Ion Permeability Texas Project Title: “Investigation of Alternative Supplementary Cementing Materials (SCMs)”— University of Texas Austin - 0-6717 Note: TxDOT has funded many research projects related to HPC. These report can be found at: http://library.ctr.utexas.edu/dbtw- wpd/textbase/websearchcat.htm. Virginia SCC in substructure repairs, lightweight SCC Washington Shrinkage test with WSU. Concrete mix test with UW. Concrete mix test for floating bridges with WSU 5. RESEARCH 31. Please list any research in progress by your agency related to HPC. Agency Research in Progress Arizona HPC project study and monitoring the bridge HPC deck

72 Florida Effective means to evaluate concrete in all applications so that we can move towards performance specifications. To me this is the one facet of the performance specification puzzle that has not been completed. If we had reliable NDT tests that could tell us that we had the compressive strength that we need for design and the durability to meet the environmental needs, this could be a major shift of our philosophy towards acceptance of concrete. Louisiana LTRC: 03-7ST (Bruce et al. 2009) Michigan Development of a durability test or tests. An accelerated method to determine if proposed developments will provide the extended service lives that our bridges must meet. Tests that can be performed on plastic concrete would be particularly useful. New Mexico The concept of HPC needs to be extended to PCCP. We are currently implementing very similar performance requirements for PCCP to improve performance of our concrete pavements. Pennsylvania Several types of structures and conditions could be studied to see how they can be improved to reduce deck cracking, such as integral abutments due to the longitudinal restraint. Are expansive additives or polypropylene fibers effective in reducing deck cracking and improving deck performance. Also, when decks crack, what are the most cost-effective means of sealing cracks to reduce future maintenance. South Carolina Permeability and shrinkage cracks Virginia Emphasize durability, avoid high strength in decks, consider shrinkage, elastic modulus, and creep for reduced cracking 33. Please list any agency research reports that document the performance of HPC in bridges and are available to be referenced in this synthesis. Please provide links or upload files in Question 35. Agency Research Reports about Performance of HPC in Bridges Alabama ALDOT Research Project No. 930-373 (Stallings and Eskildsen 2001 and Stallings and Porter 2002) Colorado http://www.coloradodot.info/programs/research/pdfs/2003/newdeckcracking.pdf/view http://www.coloradodot.info/programs/research/pdfs/2001/bridgedeckmix.pdf/view http://www.coloradodot.info/programs/research/pdfs/2010/classhconcrete/view Michigan Research reports available at http://www.michigan.gov/mdot/0,1607,7-151-9622_11045_24249--- ,00.html#BRIDGES_STRUCTURES North Carolina Behavior of a New High Performance Concrete Bridge on US 401 Over Neuse River in Wake County (Project ID 2002-17) and Kowalsky et al. 2002 and 2003 Pennsylvania See PACA undated South Dakota SD2002-02 Improved Concrete Mix Designs for Bridge Deck Overlays, SD2000-06 Optimized Fly Ash Content in PCC for Structures. SD1998-06 Evaluation of High Performance Concrete in Two Bridge Decks and Prestressed Girders (Ramakrishnan and Sigl 2001) Virginia VDOT’s Research Center (VCTIR) has publications that deal with HPC: http://vtrc.virginiadot.org/Allpubs.aspx. Washington Through WSDOT Research Office—Please contact Kim Willoughby at willowk@wsdot.wa.gov. 32. Please list any recommendations for future research needs related to HPC. Agency Recommendations for Future Research District of Columbia Causes of bridge deck cracks