Progress in Developing Self-Consolidating Concrete (SCC) Constituting Recycled Concrete Aggregates: A Review

Recycled concrete aggregate (RCA) derived from demolition waste has been widely explored for use in civil engineering applications. One of the promising strategies globally is to utilize RCA in concrete products. However, the use of RCA in high performance concrete such as self-consolidating concrete (SCC) has only been studied in the past decade. This paper summarizes recent publications on the use of coarse and/or fine RCA in SCC. The high-water absorption and porous structure of RCA, as expected, have been a challenge to produce high fluidity mixture. According to the analysis of published data, a lower strength reduction (within 23% regardless of coarse RCA content) is noticed in SCC as compared with vibrated concrete, possibly attributed to the higher paste content in the SCC matrix which enhances the weak surface layer of RCA and interfacial transition zone. Similarly, SCC tends to become less durable with RCA substitution, though the deterioration can be minimized by using treated RCA through removal and strengthening the adhered mortar. To date, the information reported on the role of RCA on the long-term performance of SCC is still limited, hence a wide range of studies are needed to demonstrate the feasibility of RCA-SCC in field applications.