Experimental Investigation on the Mechanical and Durability Properties of Sustainable Bricks Manufactured Using Waste Plastic and River Sand

Abstract

The increasing generation of waste from plastic creates a persistent solid-waste management challenge, while traditional clay brick production consumes natural resources and can impose environmental burdens. This study investigates the feasibility of converting selected waste plastics into sand-based masonry units and evaluates their physical and mechanical performance against conventional clay bricks. Waste compact discs and post-consumer plastic water bottles were cleaned, dried, reduced in size, heated, and combined with river sand. The reported experimental program used a plastic-to-sand proportion of 1:1.5 by weight for specimen preparation, with moulded specimens cooled before testing. Bulk density, water absorption, apparent porosity, and strength were also evaluated. The waste-plastic specimens showed lower density and substantially lesser water absorption and apparent porosity than the normal clay-brick specimen. In the reported comparison, the plastic-bottle specimen achieved a compressive strength of 10.6 MPa, compared with 1.77 MPa for the normal clay brick, while the compactdisc specimen reached 10.0 MPa. A separate set of project results also reported compressive strengths of 4.78 MPa and 4.65 MPa for plastic-sand bricks at 1:2 and 1:3 ratios, respectively. Overall, the findings indicate that waste-plastic–sand composites have potential as an alternative brick material, particularly where reduced water absorption, lower unit weight, and effective utilization of plastic waste are desirable. Further standardized testing is recommended before structural application.