Recycled Mixed Plastic Fine Aggregate in Cement Concrete

Abstract The literature extensively examines the utilization of sorted single-type plastic waste from post-consumer waste streams as a sustainable substitute for natural sand in cement concrete. However, severe heterogeneity of plastic waste in municipal solid waste streams, including variations in polymer types, grades, shapes, sizes, and cross-contamination with other commingled waste materials, poses a significant challenge in adopting findings from prior research that necessitates high-purity single-type plastic waste for concrete applications. This paper reports the characterization of cement concrete incorporated with mixed plastic fine aggregate (rMPFA) containing an optimized blend of plastic types produced using a proprietary mixed plastic recycling process. Five concrete mixtures containing 0% (M0), 10% (M10), 20% (M20), 30% (M30), and 40% (M40) rMPFA by volume of natural sand were investigated in this study. The laboratory results show that concrete mixture M20 had comparable compressive strength and water penetration test results when compared to control mixture M0. Additionally, toxicity characterization of concrete mixture M20 demonstrated a reduction of heavy metals in the leachate solution when compared to control mixture M0. Furthermore, microplastic detection analysis results of concrete mixtures M0 and M20 were comparable and stable.