THE PERFORMANCE OF CONCRETE CONTAINING HIGH VOLUMES OF RECYCLED MATERIALS FOR USE IN PAVEMENT APPLICATIONS

Abstract

America’s roadway system is in need of a more sustainable, efficient, and innovative plan to improve the condition if its infrastructure. As a possible solution, this research focuses on using recycled concrete aggregate and waste by-products to not only provide a structurally sound system but also decrease cost and increase sustainability, all while diminishing negative environmental impacts. A variety of tests were performed in order to determine the success of a possible solution. Typical aggregate tests were performed on each aggregate used (sand, coarse #57 rock, recycled coarse concrete aggregate, recycled fine concrete aggregate) and compared to Oklahoma Department of Transportation (ODOT) Class A standards. Upon meeting ODOT’s standards, the coarse aggregates were tested for texture and angularity. After aggregate testing was complete, a series of four mix designs were developed. The first mix design, Series No. 1, varied only the percentage of recycled concrete aggregate used to replace coarse #57 rock. The second mix design, Series No. 2, varied only the percentage of fly ash used to replace cement. Series No. 3 varied the percentage of recycled concrete aggregate (which replaced coarse #57 rock) and varied the percentage of fly ash (which replaced cement). The final mix, Series No. 4, varied the percentage of recycled fine aggregate in place of sand. Series Nos. 1 through 3 were studied extensively, focusing on fresh and hardened concrete properties and behaviors. Series No. 4 was essentially studied for workability data and strength results. Results from this research prove that concrete containing high volumes of recycled materials can meet ODOT Class A strength requirements. More study is required to determine the durability of sustainable concrete.