Sustainable utilization of mixed healthcare waste as aggregate in lightweight concrete mixes: mechanical behavior, water absorption and leaching studies

Abstract

Wastes generated from healthcare practices are a serious problem for humans as well as for the environment. In this study, an attempt was made to use mixed solid medical waste (WPN) which consisted of shredded waste plastic and chopped waste needles for partial replacement of natural fine aggregate (sand) in concrete mixes at 0%, 2%, 4%, 6%, 8% and 10% by weight. To examine the validity of the suggested approach, the fundamental concrete properties including workability, fresh and hard densities, water absorption, compressive strength, and flexural strength as well as a leaching test were performed. The curing ages for the concrete mixes were considered to be 7, 14, and 28 days. Fifty-four cubes were molded for compressive strength test, and 72 prisms were cast for flexural strength, whereby 162 cubes were prepared for density tests as well as water absorption test. The results revealed that WPN-concrete mixes exhibited improvement in the workability and steadily decreased both the compressive and flexural strength values of the WPN-concrete mixes which were higher than the mean target strength of lightweight concrete grade M17. Leaching test results indicated the absence of the target components in the leachant. The outcomes of this experimental study demonstrated that reusing WPN as a sand-substitution aggregate in concrete is a good approach to reducing the adverse impact resulting from the improper management of healthcare and medical solid waste.