Physio-Mechanical and Thermal Properties of Concrete Produced by Partial Replacement of Sand with Plastic Fines

Mechanical & Thermal performance of plastic waste concrete

Abstract

Abundant plastic waste is generated around the globe annually and safe management of this waste is crucial for the health of our environment. This study examined the physical and mechanical properties of plastic waste concrete (PWC) formulated by partially replacing natural sand with plastic fines. The sand was substituted by a mixture of two inert and non-recyclable plastics (PVC and polyethylene) in varying replacement ratios (5, 10, and 20% by volume of sand). Fresh and hardened properties of PWC mixes were evaluated. Considering possible degradation in the toughness of plastic particles due to lower melting and softening point, the effect of temperature on PWC was determined simulating heat exposure expected in hot regions of Pakistan. Various concrete specimens were exposed at 65 oC for a day and compressive strength was compared. Plastic fines caused a reduction in the workability of concrete, but it was acceptable at 10% replacement. Concrete density reduced with plastic fines content producing
lighter concrete, while, water absorption remained un-affected within 10% replacement. Mechanical strength was reduced with increasing plastic share; about 41.67% and 29% drop in compressive and split-tensile strength was recorded, respectively, for 20% sand replacement; however, within 10% replacement, the properties were favorable. Thermal exposure did not affect much and was hypothesized to have a negligible effect in normal applications. Sand replacement with 10% plastic fines would produce lighter and economical concrete along with resource-conservation and waste reduction benefits.