Performance Assessment of Concrete Incorporating Low-Density Waste Plastic Aggregates

The growing concern over plastic waste pollution and the urgent need for sustainable construction practices have prompted exploration into alternative materials for concrete production. This study investigates the feasibility of utilizing lowdensity, dust-coated waste plastic aggregates as a partial replacement for conventional coarse aggregates in concrete. The objective is to assess how the incorporation of recycled plastic influences the physical, mechanical, and durability properties of concrete, with the goal of developing a lightweight, eco-friendly alternative for use in non-structural and potentially structural applications. A comprehensive experimental program was undertaken, including the preparation of plastic aggregates from assorted waste sources, coating them with fine aggregate dust, and incorporating them into concrete mixes. Tests were conducted to evaluate workability (slump test), compressive strength, flexural strength, split tensile strength, water absorption, density, and specific gravity. Results showed that while the inclusion of plastic aggregates generally reduces mechanical strength compared to traditional concrete, dust-coating significantly mitigates this reduction, particularly at lower replacement ratios such as 10%. The best performing mix maintained sufficient strength and workability within acceptable limits for non-loadbearing applications. Furthermore, the study revealed that plastic aggregate concrete exhibits improved thermal insulation and reduced density, making it suitable for lightweight construction needs. The environmental benefits are substantial, as this approach reduces dependence on natural aggregates, lowers the carbon footprint of construction, and provides a productive avenue for reusing plastic waste that would otherwise contribute to landfill and marine pollution. Microstructural observations and economic analyses further support the viability of this material, especially when performance optimization techniques, such as surface treatment and controlled mix design, are applied. The study concludes that dust-coated waste plastic aggregates offer a sustainable alternative to traditional materials, promoting circular economy principles and environmentally responsible construction. Continued research and development in this area could pave the way for broader adoption in the construction industry.