Recycled plastic granules and demolition wastes as construction materials: Resilient moduli and strength characteristics

Abstract

Vast quantities of plastic and demolition wastes are generated annually by municipal and commercial industries in all developed and developing countries. The sustainable usage of recycled plastic and demolition wastes as alternative construction materials has numerous environmental and economic advantages. New opportunities to recycle plastic and demolition wastes into alternative resource materials for construction industries would mitigate landfill issues and significantly reduce global carbon emissions. Infrastructure projects typically consume significant quantities of virgin quarry materials, hence the usage of plastic and demolition wastes as alternative construction materials will divert significant quantities of these wastes from landfills. In this research, three types of recycled plastic waste granules: Linear Low Density Polyethylene filled with Calcium Carbonate (LDCAL), High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE) were evaluated in blends with Crushed Brick (CB) and Reclaimed Asphalt Pavement (RAP). The blends prepared were evaluated in terms of strength, stiffness and resilient moduli. Resilient moduli prediction models were proposed using Repeated Load Triaxial (RLT) tests to characterize the stiffness properties of the plastic/demolition waste blends. Polyethylene plastic granules with up to 5% content were found to be suitable as a road construction material, when blended in supplementary amounts with demolition wastes. This research is significant, as the usage of plastics as a construction material, in combination with demolition wastes will expedite the adoption of recycled by-products by construction industries. Furthermore, the plastic blends were prepared without the requirement for any further operations, such as reshaping plastic granules into fibers, hence leading to significant energy and costs savings.