Comparative assessment of recycled concrete and recycled asphalt aggregate in pervious concrete: emphasis on strength and life cycle assessment

Pavements create an impermeable layer, contributing to a decrease in groundwater recharge and a rise in flood frequency in urban areas. Pervious concrete pavement (PCP) is considered one of the solutions to address the problems associated with impermeability. Due to the low-strength applications of PCP and to address the environmental issues associated with recycled concrete aggregate (RCA) and recycled asphalt pavement (RAP), studies have used them as replacements for natural aggregate (NA). Past studies recommended the optimum RCA or RAP content based on mechanical and durability investigations. This study investigates strength and environmental aspects of using RCA and RAP in PC by replacing NA with RCA and RAP at 30, 60, and 90% by volume. The compressive strength of RCA-PC mixtures at 7 days was found to be higher than that of RAP-PC mixtures, while RAP-PC mixtures displayed better abrasion resistance. Total embodied energy (TEE) and greenhouse gas emissions (GHG) with 90% replacement of RCA and RAP were 6.5-7.5% and 12.5-13.42% lower than control mixtures for different transportation distances, respectively. The cost-per-strength ratio indicated that RCA-PC mixtures were more preferred than RAP-PC mixtures. Overall, the study recommends 30% RCA/RAP content in PC, considering strength, cost, and environmental aspects.