Stiffness Properties of Recycled Concrete Aggregate with Polyethylene Plastic Granules in Unbound Pavement Applications

Abstract

The growing population in the modern world has resulted in an increase in waste generation and stockpiles. There have been increasing concerns on how to sustainably reuse wastes in civil and geotechnical engineering applications. Two major municipal waste streams are plastic wastes and recycled concrete aggregate (RCA) generated by demolition activities. A potential application for growing stockpiles of plastic and RCA waste is in the construction of roads because pavement base and subbases typically demand significant quantities of construction materials. In this research, RCA was blended with low-density polyethylene (LDPE) and high-density polyethylene (HDPE) plastics. A range of geotechnical tests such as California bearing ratio (CBR), unconfined compressive strength (UCS), and repeated load triaxial (RLT) tests were conducted on RCA–HDPE and RCA–LDPE blends. Comparison of CBR, UCS, and RLT results with those of typical quarry materials indicated that RCA–HDPE and RCA–LDPE can be used sustainably in the construction of pavement base and subbase layers. RLT testing results were further evaluated using resilient moduli models to characterize RCA–HDPE and RCA–LDPE performances under simulated traffic loads.