Experimental investigation on the utilization of e-waste, plastic waste, and crushed coconut shell as partial replacements for natural aggregates in concrete

In a rapidly urbanizing world, the construction industry must address the requirements of society, including building safety and environmental protection. Achieving sustainable and ethical development requires the close integration of buildings with the surrounding environment. This research explores the findings from experiments investigating the impacts of substituting a portion of the coarse aggregate with plastic waste, e-waste, and crushed coconut shell (CCS) within the concrete mix (M25-grade ordinary Portland cement, fine aggregate, and coarse aggregate). The experimental results in this research represent that including 5-10% by weight of plastic, e-waste, and CCS as partial replacements for coarse aggregate in concrete mix brings significant and considerable compressive and flexural strength on the 3rd, 7th, 14th, and 28th days. Specifically, the compressive strength reaches 21.8 MPa after 5% replacement of coarse aggregate and 19.4 MPa after 10% substitution of coarse aggregate on the 28th day. However, it is noted that increasing the amount of this waste material beyond 10% results in a decline in the compressive strength and flexural strength of concrete. Therefore, as per experimental outcomes, 10% is the optimal proportion found for partial replacement of coarse aggregate with CCS, plastic, and e-waste in the concrete mix. The combination of these wastes in suitable ratios can be applied as possible and workable alternative substitutes for ordinary construction materials while maintaining environmental friendliness and affordability.