University of Washington

PACTRANS RESEARCH LEADS TO RECYCLED CONCRETE LEGISLATION Research from Washington State University has led the Washington State Legislature to recently pass Bill 1695 that calls for the use of recycled concrete in future building projects. Based on the PacTrans research project, "Evaluation of Recycled Concrete as Aggregate in New Concrete Pavements," for the Washington Department of Transportation (WSDOT), Haifang Wen, WSU associate professor of civil and environmental engineering, found that recycled concrete performs just as well as newly manufactured concrete. UTC Spotlight Many concrete roadways managed by the Washington State Department of Transportation (WSDOT) have surpassed their original design life and expected traffic loading, but due to costs associated with replacement, much of this needed replacement has been backlogged. Both the Federal Highway Administration and the WSDOT are interested in alternatives that promote cheaper and more sustainable pavement construction practices. Recycled concrete aggregates (RCA) can reduce costs, environmental impacts, and project delivery time when used in concrete pavements. Wen and his colleagues performed multiple tests to characterize RCA properties and determine if RCA had any effects on the properties of fresh concrete and hardened concrete. RCA had no significant effects on the compressive strength, modulus of rupture, coefficient of thermal expansion, drying shrinkage, or freeze-thaw durability of hardened concrete for up to a 45% replacement of coarse RCA for natural coarse aggregate. The concrete industry, which was very interested in Wen's research, took this research to the legislature this past year. By January 2016, the bill mandates a minimum use of 25% recycled concrete and a higher percentage in the future, with usage steadily increasing in the subsequent years. The research project was selected by AASHTO as a 2014 Sweet Sixteen High Value Research Project with WSDOT Secretary Lynn Peterson receiving the award on behalf of WSDOT and the research team. The AASHTO Sweet Sixteen High Value Research Projects were selected out of 180 research projects nominated by state highway agencies. Mandatory concrete recycling paves the way for new possibilities for PacTrans, as Wen and colleagues will have more opportunities to work with the Washington State Department of Transportation and other government agencies to continue improving sustainability in transportation and infrastructure. 8 Pacific Northwest Transportation Consortium

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