Experimental investigation on flexural strength and environmental performance of concrete prepared with recycled polypropylene plastic as fine aggregate

Material waste is a major contributing factor harming the ecosystem primarily due to challenges in recycling garbage and the limited reuse of materials. Plastic is also a major source of solid waste with a significant environmental impact. Therefore, this research aimed to investigate the incorporation of recycled polypropylene (RPA) plastic in concrete, examining the effect on flexural strength and environmental impact. The environmental metrics evaluated included global warming potential (GWP), abiotic depletion potential (ADP), acidification potential (AP), and eutrophication potential (EP). The research further incorporated RPA plastic granules at volumes of 10%, 20%, and 30% as a replacement for fine aggregate in concrete. After 28 days of curing, both flexural strength and environmental impact were assessed. The results showed that adding RPA into concrete mixture slightly reduced flexural strength, though the reduction remained within acceptable limits. Specifically, strength activity index (SAI) sets an allowable reduction threshold of 25%, permitting optimal RPA usage at 10%, 20%, and 30% for a water/cement ratio (w/c) of 0.45, and 10% and 20% for a w/c of 0.55. Additionally, the environmental impact analysis showed no significant effects suggesting RPA as an environmentally friendly material for concrete production.