Effect of Partial Replacement of Cement with Ceramic Waste and Discarded Tyre as Coarse Aggregate on the Properties of Concrete

Abstract

Concrete is a composite construction material formed by combining a binder (cement or lime) with fine and coarse aggregate, water, and, where required, admixtures; its strength and quality depend heavily on the proportions used in the mix. Because concrete is the most widely used construction material by tonnage, extensive research has examined the effects of partially or fully replacing its constituents with alternative and waste materials. This study investigated the effect of partially replacing cement with ceramic waste and coarse aggregate with discarded (shredded) tyre on the fresh and hardened properties of concrete. Ceramic waste was substituted for cement and shredded tyre was substituted for coarse aggregate at replacement levels of 0%, 5%, 10%, 15%, and 20%, across all combinations of the two materials. Concrete cubes were cast for each mix, cured, and crushed at 7, 14, 21, and 28 days to determine compressive strength development. Regression analysis was performed on the 28-day (ultimate) strength values to establish a mathematical relationship between percentage ceramic waste replacement and compressive strength at each fixed tyre-replacement level. The regression equations indicate that compressive strength decreased consistently as the proportion of either ceramic waste or discarded tyre increased. These findings suggest that, while ceramic waste and discarded tyre can be incorporated into concrete as partial replacement materials, their proportions should be limited and optimized to avoid unacceptable strength loss, particularly in structural applications.