Mechanical performance of concrete using rice husk ash–plastic artificial aggregates with varying particle sizes

Abstract

The increasing consumption of plastic and its long decomposition period necessitate innovative strategies for utilizing PET plastic waste in civil engineering applications, particularly through its conversion into artificial coarse aggregates for concrete. This study investigates the effect of rice husk ash (RHA) fineness used as a filler in PET-based artificial aggregates on the mechanical properties of concrete. Three RHA particle sizes were considered: ASP50, ASP100, and ASP200. PET plastic waste and RHA were mixed at a ratio of 1:4, melted, cast, and crushed to produce artificial coarse aggregates with particle sizes ranging from 5 to 10 mm. Concrete specimens were prepared in cylindrical molds and tested for compressive strength and split tensile strength at 28 days. The results showed that concrete incorporating ASP200–PET aggregates achieved the highest compressive strength (17.42 MPa) and split tensile strength (1.58 MPa) among the modified mixtures. A consistent improvement in mechanical performance was observed with decreasing RHA particle size, attributed to better particle packing and denser concrete. However, the mechanical properties of concrete containing artificial PET aggregates remained lower than those of conventional concrete with natural aggregates. Despite this reduction in strength, the significant decrease in concrete density indicates the potential of RHA–PET artificial aggregates for lightweight and non-structural concrete applications.