Repurposed Waste Linear Low‐Density Polyethylene Plastic and Waste Glass in Cement‐Less Composite Blocks for Construction Applications

As global urbanization accelerates, the challenge of managing plastic and glass waste persists, with most waste ending up in landfills due to inadequate recycling strategies. In Kenya, these issues are compounded by the high cost and inconsistent quality of conventional cement‐based masonry blocks, which also contribute to elevated carbon emissions. While various studies have incorporated waste plastic into concrete as aggregate or fiber, few have explored its use as a primary binder in combination with waste glass. In this study, carried out in Kenya, cementless composite blocks were developed using waste linear low‐density polyethylene (LLDPE) plastic as a binder and waste glass as reinforcement. The composites were evaluated for mechanical, durability, and thermal properties and benchmarked against conventional cement‐based blocks commonly used in the region. The results show that plastic/glass composites had lower densities (1237–1600 kg/m³) than cement‐based blocks (1879–2129 kg/m³). At an optimal plastic‐to‐glass ratio of 1:2, the composite achieved compressive, tensile, and flexural strengths of 11, 2.6, and 7.5 MPa, respectively, exceeding local minimum standards for nonload‐bearing masonry. Water absorption was <1%, significantly lower than that of cement‐based references (>2%), and microstructural analysis confirmed uniform glass dispersion. These findings suggest that cementless blocks produced from local plastic and glass waste offer a viable, eco‐friendly, and potentially more affordable alternative to conventional masonry units in Kenya, addressing both construction quality and waste management challenges.