The increasing generation of automotive shredder residue (ASR) from scrap vehicle recycling presents a significant environmental burden. Mixed plastics, a major heterogeneous ASR component, are difficult to recycle using conventional methods. This study evaluates the use of ASR plastics as a partial replacement for natural sand in concrete. ASR samples sourced from an Australian metal recycler were characterised, showing that rigid plastics constitute a significant fraction (13.8 wt%) suitable for sand substitution. Concrete mixes were prepared by replacing natural sand with ASR plastic aggregates at various volumetric percentages, and their physical, mechanical, and long-term durability properties were evaluated. The results showed that the reductions in all mechanical properties were significantly lower than those reported in previous mixed plastic studies. At maximum replacement rate of 45%, the slump was 40 mm, and the fresh and dry densities were 2200 and 2019 kg/m 3 , respectively. Compared with control groups, the compressive strength (36.79 MPa), flexural strength (6.06 MPa), splitting tensile strength (4.64 MPa), and modulus of elasticity (27.64 GPa) were reduced by 35%, 25%, 24%, and 36%, respectively. Microstructural analysis identified fibrous features and glass-fibre-reinforced composites within the ASR plastics, which may account for the relatively moderate declines in performance. Durability testing under one year of acid and sulphate exposure showed that ASR-modified concretes performed comparably or slightly better than controls. These findings demonstrate the potential of ASR plastics as a sustainable fine aggregate alternative, offering a viable upcycling route for plastic-rich waste streams in concrete production. • First material characterisation of automotive shredder residue in Australia. • Key properties of concrete with ASR plastics thoroughly examined. • ASR plastic concrete shows superior performance compared to past studies. • Long-term durability shows ASR plastics can partially replace natural sand. • SEM analysis reveals fibrous features and the presence of GFRC in ASR plastics.
Rao et al. (Sat,) studied this question.