Plastic Wastes as a Raw Material in the Concrete Mix: An Alternative Approach to Manage Plastic Wastes in Developing Countries

Abstract

The twenty-first century can be marked as a “plastic era” where different sectors are producing and consuming a huge amount of plastic. Concurrently, the plastic waste generation rate has been increasing and causing serious problems on the public health and ecosystem. Hence, recycling of plastic wastes can be one alternative management option for this peculiar waste stream. This study aims to evaluate the technical feasibility of plastic wastes as a partial replacement of coarse aggregate in a concrete mix using volcanic pumice as an admixture. Concrete test specimens prepared with standard M20 mix design were measured for a compressive and split tensile strength. Plastic aggregate made from plastic bags and bottles has shown a different degree of workability to replace the concrete mix. The compressive and split tensile strength tends to decrease with increasing the ratio of plastic aggregates for both types of plastics. However, the curve based operational cut-off value shows that the plastic bag and bottle aggregates can replace coarse aggregate from 11-14% and 35-37.5% respectively. Conclusively, utilizing the plastic aggregates as a partial replacement of coarse aggregate is technically feasible. However, applying the nominal concrete standard mix proportion is seemingly inappropriate while plastic aggregates used as an aggregate which in turn require a specific mix design. Despite the percent replacement is low, utilizing waste plastics in the concrete mix would help countries with the weak waste management system.