Concrete Technology for Transportation Applications (2019)

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1 The past few years have seen some significant advances in concrete technology. For example, newer concrete incorporating advances in admixtures and cementitious materi- als has emerged. High-strength concrete (HSC) and ultrahigh-strength concrete (UHSC), and self-consolidating concrete (SCC) have found widespread use in bridge members to facilitate and accelerate construction. Ultrahigh-performance concrete (UHPC) is becom- ing an essential material for joints connecting prefabricated elements in accelerated bridge construction and has also seen uses in bridge overlays. High early strength concrete (HESC), very high early strength concrete (VHESC) and other rapid-repair materials are increasingly being used for accelerated construction and repairs of pavements and bridge decks. Roller- compacted concrete (RCC), which has been used for military, industrial, and port facilities, is now also becoming a growing part in state pavement construction. Pervious concrete (PC) has also found uses in stormwater management applications, in street pavement con- struction, and in base layers and drainage systems for highway pavements. Internally cured concrete (ICC), precast concrete pavements (PCPs), and performance-engineered mixtures (PEMs) are subjects of increasing interest and implementation efforts by a growing number of state departments of transportation (DOTs). Also, the DOTs are more aware of the need for the temperature control of mass concrete (TCMC) to preserve integrity and long-term durability of the massive element. Concrete technology is also facing some emerging challenges that need to be addressed. These include the present or future depletion of high-quality aggregates in some parts of the country, changes to power generating plants that will reduce the supply and consistency of acceptable fly ashes, and the incorporation of reclaimed or traditionally landfilled materials such as recycled concrete aggregate (RCA) into concrete. Challenges may also include having to overcome barriers to the incorporation of new concrete technologies into transportation projects. Such barriers may include institutional and cultural resistance at the agency and by industry and insufficient training. Although information about these concrete technologies is available in published literature, there do not appear to be resources for the DOTs and industry on the advanced and emerging concrete technologies and their applications and best practices. Beneficial to DOTs would be information on the need for the technology, benefits, types of applications, performance, experiences from state and industry implementations, as well as limitations and gaps in the technology information and barriers to wider implementation of some technologies. The objective of this synthesis study is to provide (1) an overview of advanced and emerging concrete technologies suitable for transportation applications, (2) state DOT applications and practices of the technologies and performance of these technologies, and S U M M A R Y Concrete Technology for Transportation Applications

2 Concrete Technology for Transportation Applications (3) information on gaps in the technologies and in implementation efforts that may be addressed to expand their use. In this synthesis, information has been collected from a review of the literature and from a survey of state DOTs. This report presents technical information that has been synthe- sized from review of standard practices, reports, and technical papers. These include, but are not limited to, American Concrete Institute standard practices; FHWA state DOT and industry reports; and research papers from universities and research organizations, domes- tic and international. A survey questionnaire was prepared and electronically transmitted to the AASHTO Committee on Materials and Pavements members of the 50 states and the District of Columbia. Forty state DOTs responded to the survey questionnaire and five states prepared case examples of technologies implemented in their states as well as barriers and solutions to technology implementation. Specific technologies covered in this report include HSC, SCC, ICC, UHPC, TCMC, PCP, RCC, PC, RCA, HESC and repair materials, and PEMs. The synthesized information from literature review on each technology includes need for the technology, types of applications, benefits and limitations, materials and mixtures, properties and characteristics, construction guidelines and specifications, implementation, and performance. The report also presents results of the survey responses from 40 states: AL, AZ, AR, CO, CT, DE, FL, GA, ID, IL, KS, KY, LA, ME, MA, MI, MN, MS, MO, MT, NE, NH, NJ, NY, NC, ND, OH, OR, PA, RI, SC, SD, TN, TX, UT, VT, WA, WV, WI, and WY. The survey information identifies the states using the specific technologies and whether or not the states have developed specifications for the technologies. The information also includes types of applications in pavement and structural construction and repairs, level and extent of the experience in implementation, and specific challenges and limitation of the tech- nologies. The report also identifies many states that are experimenting with and/or have implemented other technologies not covered in the report, as well as states that are utilizing reclaimed materials such as RCAs and other landfilled materials. On the issue of shortage of quality aggregates—availability of fly ash in the United States—the information is presented in the form of number of states affected or unconcerned about these issues. Barriers to implementation of advanced and emerging concrete technologies is another topic included in the discussion of the state DOT responses. Case examples from Florida, Illinois, Missouri, New York, and Tennessee DOTs of technology implementation or of technology barriers are also presented to be shared with other DOTs. Florida presented their experience and specification requirements on mass concrete and temperature control requirements. Illinois described the effort to mitigate bridge deck cracks through the use of shrinkage-compensating or -reducing concrete and the use of ICC for bridge decks. Missouri presented a case example of a PCP project includ- ing lessons learned and gaps in the technology that require attention. New York described their use of performance tests in their bridge construction projects as part of their efforts to use the concept of PEMs. Tennessee discussed the barriers to implementation of new concrete technologies and presented some actions that would remove or lessen those barriers. From the results of the literature review and of the survey responses, a number of key conclusions have been drawn: 1. The literature review showed that implementation of advanced, emerging, and new con- crete technologies has resulted in major benefits to the transportation infrastructure. The benefits include accelerated construction, replacement and repairs of pavements and bridges (UHPC, HESC, VHESC, RCC, and PCP), better performance and improved durability (HSC, SCC, and ICC, PEM), control of temperature in massive structural

Summary 3 members to mitigate thermal cracking and improve durability (TCMC), and enhanced sustainability and environmental benefits (RCA and PC). 2. The survey responses from 40 states showed that the top three most implemented con- crete technologies are HSC (40 states), SCC (37), HESC (37), and lightweight concrete (33), and the least implemented technologies are UHSC ≥ 10,000 psi (69 MPa) (15), PC (13), and ICC (9). 3. The survey also showed the following results: a. Fourteen states (Delaware, Florida, Georgia, Illinois, Kansas, Louisiana, Maine, Missouri, New York, Ohio, Pennsylvania, Vermont, West Virginia, and Wyoming) have experimented with or implemented technologies other than those discussed in this report. b. Only three states reported depletion in quality aggregates (Florida, Maine, and Kansas). However, another 13 states predicted shortages in the future (Idaho, Louisiana, Minnesota, Montana, New Jersey, New York, North Dakota, Oregon, Pennsylvania, South Carolina, Texas, Utah, and Vermont). The remaining 24 states reported no shortages. c. Thirteen states reported current shortages in the availability of fly ash (Alabama, Florida, Illinois, Maine, Massachusetts, Michigan, Missouri, New Jersey, New York, North Dakota, Oregon, Rhode Island, and Texas), 16 other states (Arizona, Arkansas, Colorado, Connecticut, Delaware, Georgia, Idaho, Minnesota, Mississippi, Montana, Nebraska, North Carolina, South Dakota, Tennessee, Vermont, and Washington) predicted future shortages, and the remaining 11 did not report any shortages. d. The top solutions offered to address the shortage of fly ash include the expanded use of slag, use of alternative pozzolans such as metakaolin, and import of foreign ash and use, after reprocessing, to achieve a lower loss on ignition, or importing ash from other states. e. The most widely used recycled/reclaimed material in concrete applications is RCA. Fifteen states (Alabama, Colorado, Connecticut, Florida, Illinois, Michigan, Minnesota, Missouri, New York, Ohio, Texas, Washington, West Virginia, Wisconsin, and Wyoming) use RCA in pavements, and 5 states (Alabama, Connecticut, Illinois, New York, and Texas) use RCA in structural applications as well. f. Seven states have experimented with the use of other reclaimed materials in concrete mixtures. Five states (Florida, Georgia, North Carolina, Oregon, and Wisconsin) have conducted research on the use shredded/crumbed tire rubber. Four states (Florida, New York, North Carolina, and Wisconsin) have reported research on the use of bottom ash as an ingredient in concrete mixtures. Three states (Florida, New York, and Wisconsin) have experimented with the use of granulated glass in concrete. Two states (Florida and New York) have experimented with municipal waste ash, and Georgia and Rhode Island have used plastic bottle fibers. Florida has also conducted research on biomass ash. g. The top five barriers to implementation of concrete technologies by the state include – Technology not sufficiently proven to be adopted (30 states), – Too expensive to use (28 states), – Lack of experience and not enough training (27 states), – No specifications or construction guidelines available (23 states), and – Industry resistance (21 states). h. Other notable responses on the issue of barrier to technology implementation include the following: – Lack of experience by agency and local industry, – Concern about potential reduction in concrete mixture quality,

4 Concrete Technology for Transportation Applications – Ability to assess long-term concrete durability with some technologies, – Implementation challenges, and – Time and cost-effectiveness. Gaps in the information pertaining to specific technologies were also identified and provided for further attention. Some of the information gaps are the following: 1. State DOTs reported that they need more training to successfully implement new technologies. 2. The need for air entrainment in HSC and UHSC to resist freeze-thaw actions has not been completely settled by the research community. 3. Unanswered questions remain about the use of SCC in pavement repairs and slab replacements. 4. Some states indicated that sources of lightweight aggregates for ICC are not available at convenient locations to make them cost-effective. Also, there seems to be uncertainty about the expected ICC performance using lightweight aggregate from different sources. 5. Most mixtures used to produce UHPC are proprietary. This causes an increase in construction cost, according to the survey responses. 6. With respect to TCMC, there does not seem to be a consensus among the states, indus- try groups, or published research on the maximum core temperature and temperature differential between the core and surface of the structure. 7. There does not seem to be well-defined, acceptable procedures for maintenance, reser- vation, and panel replacement in a posttensioned PCP. 8. Two main barriers to expanding the use of RCC in highway pavements are control of surface smoothness and absence of effective load transfer or dowel bars. 9. The two major gaps in the PC technology are lack of a specialized paving machine to place and uniformly compact the material without damaging its void structure and availability of guidelines for design, construction, quality control testing and mainte- nance of PC pavements. 10. The most common distress problem when using HESC in replacement panels and slabs is premature cracking from thermal and nonuniform shrinkage stresses. Many states do not seem to have effective measures to mitigate the problem or guidelines for when to repair or remove the damaged slabs. 11. The long-term performance of VHESC and repair materials is not well understood, including impact of the type of application and weather conditions. Issues such as premature setting, excessive shrinkage, and cracking are areas of concern. 12. The states have shown interest in the feasibility of using alternative pozzolans to sup- plement the expected shortages in traditional fly ashes. However, they are concerned about the impact of the alternative pozzolans on short- and long-term performance of concrete. This synthesis report can benefit DOT engineers, consultants, and construction pro- fessionals as well as university researchers by providing information on the purpose, applications, and performance of concrete technologies currently used by the DOTs. The references provide more detailed information on various aspects of each technology that may be of interest to engineers, practicing professionals and the research community.