Feasibility of use of recycled concrete aggregates in drainage layer of pavements: a comparative analysis

This study explores the potential of recycled concrete aggregates (RCA) as a sustainable alternative to conventional crushed aggregates (CCA) in pavement construction, focusing on permeability, compaction, and mechanical properties. With a shortage of natural aggregates, RCA, derived from construction and demolition (C&D) waste, offers a solution to environmental and resource challenges. India, producing 150 million tons of C&D waste annually with only 1% recycled, presents a significant opportunity for RCA utilization. This research includes compaction, California bearing ratio (CBR), and permeability assessments to compare RCA and CCA. RCA showed higher porosity and irregular particle shapes, resulting in lower maximum dry density (MDD) and higher optimum moisture content (OMC) than CCA, yet meets the minimum CBR requirement for granular sub-base applications. However, RCA's lower permeability and higher breakage rates during compaction necessitate tailored mix design and compaction practices. Despite these challenges, RCA offers environmental benefits, such as reduced reliance on natural aggregates and minimized waste generation. Recommendations include advanced processing techniques to remove residual cement paste and blending RCA with CCA or stabilizing agents. This study highlights RCA’s potential in sustainable development, emphasizing the need for meticulous processing, quality control, and proper mix design to ensure effective use in pavement applications.