Effect of recycled coarse aggregate and foundry sand on the properties of self-compacting concrete

Abstract

In this paper, the possibility of utilising foundry sand and recycled coarse aggregate (RCA) obtained from a ready-mix concrete plant for making self-compacting concrete (SCC) was evaluated. In this experiment, 25 concrete mixes were made in which the substitution of RCA was 0, 25, 50, 75 and 100% as coarse aggregate and substitution of foundry sand was 0, 10, 15, 20 and 25% as fine aggregate. The cement content, water and silica fume were kept constant for all 25 mixes. The effects of foundry sand and RCA on the fresh properties of concrete and the hardened properties of SCC were evaluated. The results of the investigation showed that the hardened properties of concrete with 20% foundry sand were significantly improved when compared to conventional concrete. However, the hardened properties of the SCC with 100% RCA were poorer than for conventional concrete with 100% natural coarse aggregate. Strength decreases with the increase in percentage of substitution of RCA. It was found that an M20 grade of structural SCC was achieved with 75% substitution of RCA.