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 incorporate RCA into 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. As expected, the high-water absorption and porous structure of RCA have posed challenges in producing a high-fluidity mixture. According to an analysis of published data, a lower strength reduction (within 23% regardless of coarse RCA content) is observed in SCC compared with vibrated concrete, possibly due 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 although the deterioration can be minimized by using treated RCA through removing or strengthening the adhered mortar. To date, the information reported on the role of RCA in the long-term performance of SCC is still limited; thus, a wide range of research is needed to demonstrate the feasibility of RCA–SCC in field applications.