A Study on the Use of Waste Plastic as Partial Replacement to Sand/Fine Aggregate in Concrete

The recycling of plastic waste has emerged as one of the most significant challenges impacting the environment. It is possible that their reuse as aggregates in the production of new construction materials will assist in the elimination of these plastic wastes, which would help to safeguard the environment and promote the attainment of sustainable development. Reusing non-biodegradable plastic waste materials can be an effective strategy for decreasing the use of natural resources for construction and lowering environmental hazards. This study, therefore, explores the feasibility of using recycled low-density polyethylene (LDPE) plastic as a partial replacement for fine aggregate in concrete. The purpose of this research is to evaluate LDPE concrete's mechanical and durability characteristics. It focuses mainly on compressive strength, split tensile strength (STS), flexural strength, and water absorption. Scanning electron microscope (SEM) analysis was used to investigate the microstructure of the specimens. The experimental work includes performance of M20 grade concrete and M50 grade concrete with varying percentage of LDPE aggregate as 0%, 5%, 10%, 15%, 20% and 0%, 1%, 2%, 3%, 4%, and 5% of the weight of fine aggregate, respectively. The replacement of sand with plastic waste showed a slight decrease in compressive strength when compared to the control normal mix. This type of concrete mix can be used in many applications such as highway medians, sub-bases for highway pavements, parking blocks, and various other structures where small strength reduction will not influence the performance a lot. It also helps reduce the self-weight of concrete in structures and helps conserve natural materials such as sand in good quantity.