The effect of recycled waste polystyrene plastic aggregate on the engineering properties of lightweight composites

The substantial generation of polystyrene waste from the food industry poses significant environmental andhuman health challenges. This study addresses these issues by using recycled lightweight aggregates (RLWA)from waste polystyrene plastic as an alternative for coal bottom ash in the production of lightweight composites(LWC) incorporating ternary binder materials of cement, fly ash, and ground granulated blast-furnace slag. Toassess the impact of RLWA on LWC’s engineering performance, various proportions of RLWA were incorporated into the LWC mixtures as a fine aggregate. Results show that RLWA content significantly influenced the mechanical and durability properties of LWC. Specifically, increasing RLWA content reduced the dry densityand mechanical strength, while increasing the water absorption and drying shrinkage of the LWC. The correlations among these LWC’s properties were also examined. Notably, the LWC specimen with 50% RLWAcontent achieved the highest 28-day flexural strength of 11.06 MPa and compressive strength of 63.8 MPa,alongside the lowest water absorption rate of 5.34% with a dry density of 1896 kg/m3. These results underscore the potential of utilizing RLWA as a fine aggregate in LWC production, highlighting its feasibility for practical applications and providing information for more sustainable construction practices. By turning wastes into useful construction materials, the study not only addresses waste management issues but also contributes to the development of greener materials for sustainable growth.