Physical and Mechanical Properties of Concrete using Recycled Clay Bricks as Coarse Aggregate

Abstract

Rising construction waste due to demolition work, natural disasters, and development is becoming a prominent issue. To tackle this, Recycled Crushed Brick Masonry Aggregate (RCBMA) can be an ideal replacement for the limited Natural Coarse Aggregates (NCA) in the production of concrete, potentially assisting in managing construction waste and reducing the depletion of NCA. As such, this study focused on assessing the suitability and establishing the optimum percentage of RCBMA as a replacement for NCA in concrete. To do so, five different concrete mixes were prepared where NCA was replaced by RCBMA at different percentages (0, 25, 50, 75, and 100%). The effect of RCBMA on concrete was studied and analyzed for physical and mechanical properties including concrete slump, compressive strength, density, water absorption, and flexural strength. From the results, the workability of the concrete mixes were reduced by as much as 21.8 and 44.9% at 50 and 100% RCBMA replacement, respectively. Meanwhile, the water absorption increased with higher RCBMA replacement from 1.43 at 0% replacement to 7.76 at 100% replacement, indicating greater porosity at higher RCBMA replacement levels. The compressive strength was reduced with a rise in RCBMA replacement due to the lighter weight of RCBMA as compared to NCA. This reduction was as much as 48.72 and 63.14 at 50 and 100% RCBMA replacement of NCA. The same can be said about the flexural strength and density of concrete, where higher RCBMA replacement led to lower flexural strength and concrete density. It was concluded that a 25% RCBMA replacement does not severely affect the workability and mechanical strength of concrete (16.8 and 17% reduction in compressive and flexural strengths, respectively, as compared to the control samples) and thus can be used for structural concrete applications. The findings from this study illustrate the possibility of using RCBMA as a partial replacement for NCA, potentially assisting in reducing construction and demolition waste sustainably.