Evaluating the Utilization of Recycled Concrete Aggregate for Road Applications

Recently, reusing or recycling crushed concrete pieces and producing recycled concrete aggregate (RCA) has emerged as an effective way for controlling and managing construction and demolition waste, reducing the need for natural aggregates, protecting the environment, and saving landfill space. The purpose of this study was to investigate the feasibility of utilizing RCAs as an unconfined aggregate in road structure courses. Six types of natural aggregates (NAs) and three different types of RCAs were selected. All natural aggregates were located in suburb of Tehran. Four samples comprised of crushed aggregates used locally in building construction and two of them were river run gravel based. Also, three different types of RCAs were considered, denoted as RCA-1, RCA-2 and RCA-3. RCA-1 was chosen from a self-consolidating concrete and RCA-1 was selected from a conventional concrete and finally, RCA-3 was chosen from a landfill that consisted of several unknown concrete resources, crushed concrete and impurities. Various physical and mechanical tests including water absorption, specific weight, impact test, crushing test and Los Angles abrasion test were performed on these aggregates. The results indicated that all RCAs were accepted for general applications in road construction, expect for asphaltic layers such as surface course, binder course and mastic asphalt course. As well results illustrated that the parent concrete quality of RCAs had no considerable impact on the mechanical performance of RCAs.