Melted plastics as the exclusive binder for masonry units: A sustainable solution for the construction industry

Abstract. This study investigates the feasibility of using melted plastic wastes, specifically low-density polyethylene (LDPE) and high-density polyethylene (HDPE), as the sole binder in masonry blocks in light-load applications, addressing both environmental and construction challenges. Repurposing plastics offers a sustainable alternative owing to the increasing plastic waste crisis and high carbon footprint of traditional cement. Predetermined plastic-to-aggregate ratios (1:1.5, 1:2, and 1:2.5) were adopted to produce masonry units, and properties of hardened samples, such as compressive strength and water absorption, and the scanning electron microscopy(SEM) micrographs were assessed. From the results, the blocks made with 100% HDPE and LDPE in a 1:1.5 ratio yielded compressive strengths of 18.6 N/m2 and 15.4 N/m2, respectively, thus surpassing the control cement-based blocks by 120% and 110%, respectively. The water absorption rate of melted plastic blocks was 3% less than that of the control blocks. Although with somewhat high production cost, these melted plastic blocks offer a significant long-term environmental benefit by reducing carbon emissions and diverting plastics wastes from landfills. The study concludes that melted plastic masonry units are viable, sustainable alternative for light-load construction.