Utilization of recycled concrete aggregates for developing high-performance and durable flexible pavements

The objective of this research was to explore the feasibility of using recycled concrete aggregates (RCA) to construct flexible pavements with high performance and durability. The research is based on materials obtained from urban renewal projects in Istanbul, where RCA can be sourced from construction demolition waste. The grain diameter distributions of subbase and base samples, intended for road infrastructure implementation, were established to comply with the AASHTO Pavement Structures Design Guidelines specifications. Laboratory tests were conducted to determine the physical, mechanical, and stiffness properties of subbase and base samples prepared with RCA. In addition, the influence of freeze-thaw (F-T) cycles on the stiffness characteristics of RCA was examined experimentally through resilient modulus and permanent deformation tests carried out on base and subbase samples subjected to a range of 1 to 20F-T cycles. Also, numerical evaluations were undertaken using finite difference numerical modeling software to investigate the mechanical performance of flexible pavements built with RCA under significant loads, utilizing parameters derived after various numbers of F-T cycles. The findings suggest that the stiffness properties of RCA meet the required specifications for subbase and base materials after F-T cycles, indicating that RCA can potentially provide high performance in flexible pavement construction under varying environmental conditions.