Examining the Influence of Recycled Concrete Aggregate on the Hardened Properties of Self-compacting Concrete

摘要

Along with the growing development of countries around the world, there are huge amounts of construction and demolition works which produce large volumes of recycled concrete aggregate (RCA) and these are increasing over the past few decades. One of the more practical ways to manage the RCA wastes is through re-using them as aggregate to produce concrete. In this paper, 5-10 mm crushed RCA was used at different ratios (0, 25%, 50%, 75%, and 100% by weight) in modified self-compacting concrete (SCC) to study its feasibility as natural aggregate (NA) substitute. The results show that while the presence of RCA reduced the mechanical strengths and increased the water absorption as well as permeable voids of SCC, these effects were less pronounced compared to the use of RCA in normal vibrated concrete. Although the micro-hardness of the RCA-mortar interface was lower, the thickness of the ITZ was similar as that for NA-mortar interface. These findings suggested that SCC is a suitable matrix for incorporating RCA and based on the investigated properties, it is recommended that the maximum replacement level of RCA to be 25%.