Recycled Materials and Byproducts in Highway Applications—Coal Combustion Byproducts, Volume 2 (2013)

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49 Appendix A Agency Responses to performance, environmental, and Barrier Questions KY Concerning fly ash for embankments and stabilized soils; as mentioned previously controlling the moisture content is critical. Also, erosion control for embankments and stabilized soils containing fly ash is of the utmost importance. Concerning its use in HMA (specifically SMA in Kentucky), the spherical shape of the fly ash particulate seems to create issues within the equipment used to deliver the material into the asphalt mixing plant. The fly ash does not appear to “flow” into the asphalt mixing plant consistently. Regarding the use of Types C and F fly ash in PCC, Kentucky has experienced some environmental, durability, and aesthetic (staining) concerns. State Performance Barriers AK OK Lack of guidelines and research AL PCC routinely uses Type C & Type F fly ash and has been shown to increase performance. Type C and Type F fly ash are also routinely used in our stone matrix asphalt mixes. AR Structural and paving concrete have performed well when fly ash is used as substitute (up to 20% by weight) for Type I cement. AZ We have been utilizing Class F fly ash in PCC for many years with much success. I am not aware of any adverse affects due to the fly ash. Our specifications allow for both Class C and F; however, we have not seen any mix designs submitted using Class C. CO The Type C and F fly ash are performing well. CDOT has incorporated the applicable AASHTO standards and tests for these products. Some products are not produced in large enough quantities for practical use. DC We have experienced compressive strength problems in the past No barriers DE No performance issues Consistency with the fly ash in concrete applications GA Environmental regulations in our state limit the use of combustion ash. The demo project we are doing needed a special environmental approval and waiver. HI Availability, quality concerns, and cost ID We are using fly ash for ASR mitigation. Not enough experience. IL Our biggest use for fly ash (either C or F) is as ASR mitigation in PCC mix designs. Both perform very well for this use. IN Our experience with these products has been very positive and they are used routinely when available. IA Performance tracked for PCC only. No problems. Limits on cement substitution will always exist. KS It’s permitted within HMA, but not used by contractors. Concerning its use in embankments and stabilized soils, fly ash is a byproduct that works successfully when the optimum moisture content is maintained. In our experience, moisture contents no higher than the optimum value and no more than 2% below the optimum value are necessary for successful performance. Concerning HMA, Kentucky has attempted to utilize Type F fly ash in two SMA projects. One job was successful, and the performance of that SMA pavement has been satisfactory. Another SMA project was not successful. The volumetric properties of the SMA containing the fly ash were extremely inconsistent and, ultimately, the fly ash was not permitted as mineral filler in the SMA. Types C and F fly ash have provided acceptable results in flowable fill and PCC in Kentucky. Table a1 agency Responses To open ended QuesTion on combusTion ash (continued on next page)

ME Used to reduce perm eability of concrete— good perform ance MN Long-term environm ental concerns with unbound applications. Will it m ove ? How far ? What stuff moves in which type of soil? MO No problem s with perform ance. Fly ash stabilization is viewed as a construction- only treat me nt not for the life of the overlying pavement. Hazardous m aterial leaching perceptions Stability of ash fills MO No loss in perform ance due to these materials. Literature suggesting hazardous material content. Abundance of natural resources hinders cost-effectiveness of hauling too far from the source. MS Standard Type C or F fly ash replacem ent of cem ent is widely used in Mississippi to enhance the place me nt and in-place properties of concrete. The perform ance of concrete containing standard fly ash is very good. Because com bustion byproducts are “byproducts” there can be chem ical and physical variations in the products due to changes in the com bustion process. When looking at these ma terials as an engineered material that can sometimes be problematic. NC Performance problems not noted Source proximity to construction site (transportation cost) ND Fly ash is used extensively in PCC pavem ents with good success. Som e of the products are not produced locally. Cost to ship in from other states. NE Type F fly ash is necessary in our PCC to mitigate ASR. Type C fly ash has worked well for our soil stabilization process. Type F fly ash is changing and/or becom ing less available. NH We comm only use Type F fly ash in our concretes and it perform s satisfactorily. We allow for Type C fly ash in our specs, but it is not used. We have experi me nted with coal fly ash in flowable fill and I am not sure what the result of that was. We are investigating using bottom ash for em bankm ent. A ma nufacturer has approached us about seeing if there is a use for the particles that are too fine for use as blasting/grinding m aterials. We are testing the engineering properties of the particles. We can use them as long as it is not in a residential situation. NJ Boiler slag is not as good an embankment material (less stable) than virgin aggregate or recycled concrete aggregate. The Type F fly ash is used to mitigate ASR (alkali– silica reactivity) in PCC and has performed well. Wi th MSW concerns on possible contam inants makes this product impossible to use in our state. NV NDOT has experienced good perform ance using Ty pe F fly ash in PCC. Limited availability of other products in the geographic area NY NYS uses Class F fly ash, GGBFS, and silica fum e. These products are used to enhance PCC perform ance as a part of high perform ance concrete mi xture designs. Variable quality of some materials makes uniform PCC production difficult. OH Fly ash (C and F) in concrete have been good perform ers, but have quality issues due to lack of ASTM controls for the product. We have lim ited experience with soil stabilization, but can work. Use in flowable fills has seemed to work reasonably well. Costs versus natural materials. Correctly used there are often additional processi ng and control costs because of the non- uni form ity of t he byproducts and the additional oversight or unclear federal requirements for the materials. While governm ent agencies push or even try mandates for use of byproduct materials, they don’t actually define the additional controls needed or establish the environm ental checks required. This leads to misleading information presented by suppliers and inconsistent environm ental mandates from different arms of federal and/or state or even regional agencies. MD Fly ash was used (late 1990) as fill em bankm ent in one state project, all observations indicate that the em bankm ent is stable and monitoring wells did not show any changes in ground water. MDE is investigating further. The fly ash was used as subgrade stabilization for a few projects in Maryland. We need additional information to know mo re about the short- and long-ter m perform ance of these mate rials before using for highway projects. LA Types C & F fly ash have been used successfully in PCC for several years. Potential for alkali reactivity with certain aggregates with Type C ash. MA Fly ash & slag in concrete has worked well. Still not sure of application value in other areas of transportation projects. Table a1 (continued)

51 TX Fly ash: Texas experience with Type C and F fly ashes, modified class F fly ash, and ultra-fine fly ash have been quite positive. In fact our standard specification for hydraulic cement concrete has 5 of 8 mix design options allowing some amount of cement replacement with fly ash. We have found that fly ash improves durability and can prevent or at least lessen the impact of alkali–silica reactivity. TxDOT Atlanta district has constructed six test pavements using hydrated fly ash as a base over a five-year period. All pavements have performed well, with only one pavement exhibiting a significant amount of distress, and that was in its eighth year of service. TxDOT has also been trying to use a combination of lime and Type F or GGBFS to mitigate the sulfate-induced soil heave problems. Bottom ash: HMA produced with bottom ash has performed well. When HMA is produced with bottom ash the optimum asphalt content (OAC) is generally greater than 6%, which produces a durable mix. The bottom ash stiffens the mixture, which makes it less prone to rutting and the high OAC produces a thicker film of asphalt and makes it less prone to cracking. HMA: no significant barriers. Bottom ash makes the mix a little bit dry and a little harder to achieve the density. Type F fly ash can slow the heat of hydration of hydraulic cement concrete, but if considered in construction planning it is not an issue. UT Required to mitigate ASR in PCC UDOT rarely requires formulation. Most of our specs are performance driven. VA Coal ash–PCC—In VA, contractors cannot use PCC unless a minimum of 25% of its content consists of fly ash. Type C and F fly ash—VA has had really good success in the use of these industrial products in embankments and PCC. If coal ash needs to be stabilized by adding lime or cement sometimes crystal formations may grow that will cause problems if used near structures. VT Generally, we have had very good performance from coal ash and blast slag. Occasionally, variable LOI may be contributing to loss of air in the concrete. They are a principal agent in the fight against alkali–silica reactivity and required in all bridge decks in VT Early strength requests by contractors routinely do not address longer-term strength gains. The cost savings is not realized because the pozzolans are supplementing cement rather than replacing—so, cementitious contents are high. WI Aiding fly ash allows the concrete to have more slump with the same quantity of water. Blending Class C with Class F fly ash is better than either Class C or Class F alone. The higher the fly ash content the higher the scaling. WA Fly ash, micro silica, and GGBFS have all been allowed and used by WSDOT as alternative cementitious materials. The performance has been generally good. Most barriers come from lack of availability, cost, and lack of silo storage space. PA Type F fly ash has been used in PCC to mitigate ASR with good success. However, some fly ash results in low air contents in plastic and hardened PCC. Fly ash used in some soil stabilization (subgrade) projects and performance was satisfactory. Clean, consistent product supply that translates into consistent performance. Stiffer emission regulations changing the characteristics of combustion byproducts. SC The use of fly ash is encouraged because it is believed to inhibit alkali–silica reactivity in PCC. Supply, environmental concerns, lack of data on long-term performance Table a1 (continued)

Abbreviations used without definitions in TRB publications: A4A Airlines for America AAAE American Association of Airport Executives AASHO American Association of State Highway Officials AASHTO American Association of State Highway and Transportation Officials ACI–NA Airports Council International–North America ACRP Airport Cooperative Research Program ADA Americans with Disabilities Act APTA American Public Transportation Association ASCE American Society of Civil Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials ATA American Trucking Associations CTAA Community Transportation Association of America CTBSSP Commercial Truck and Bus Safety Synthesis Program DHS Department of Homeland Security DOE Department of Energy EPA Environmental Protection Agency FAA Federal Aviation Administration FHWA Federal Highway Administration FMCSA Federal Motor Carrier Safety Administration FRA Federal Railroad Administration FTA Federal Transit Administration HMCRP Hazardous Materials Cooperative Research Program IEEE Institute of Electrical and Electronics Engineers ISTEA Intermodal Surface Transportation Efficiency Act of 1991 ITE Institute of Transportation Engineers MAP-21 Moving Ahead for Progress in the 21st Century Act (2012) NASA National Aeronautics and Space Administration NASAO National Association of State Aviation Officials NCFRP National Cooperative Freight Research Program NCHRP National Cooperative Highway Research Program NHTSA National Highway Traffic Safety Administration NTSB National Transportation Safety Board PHMSA Pipeline and Hazardous Materials Safety Administration RITA Research and Innovative Technology Administration SAE Society of Automotive Engineers SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (2005) TCRP Transit Cooperative Research Program TEA-21 Transportation Equity Act for the 21st Century (1998) TRB Transportation Research Board TSA Transportation Security Administration U.S.DOT United States Department of Transportation