Effect of loading-induced damage on chloride ingress behavior of recycled aggregate concrete: A comprehensive review

The recycling technology of construction and demolition wastes is an inevitable choice towards the sustainable development of the construction industry, aiming at addressing the problems of raw materials shortage and waste disposal. The utilization of recycled coarse aggregate (RCA) in new concrete production has been identified as an effective way to reasonable application of natural resources replacement and environmental preservation. In service, external mechanical loading can easily cause the initiation and interconnectivity of microcracks inside concrete, specifically the complex multiple interface structures of recycled aggregate concrete (RAC) due to the old adhered mortar at the surface of RCAs, which can remarkably accelerate the process of water penetration and aggressive ions penetration into concrete. Thus, knowledge of mass transport properties in the loading-induced damaged RAC contributes to the durability evaluation of RAC and its extensive application in the practical engineering. This paper reviews the previous findings on the mechanical loading effects on the chloride transport properties of RAC. The effects of loading-induced damage on microstructure evolution of RAC as well as the damage characteristics were discussed. The research progress on the chloride ingress behavior of RAC subjected to mechanical loading was highlighted from the viewpoint of testing method, loading devices and numerical calculation, and the modified effects on the transport properties were further analyzed. On this basis, the future research on the durability-related properties of RAC would be finally proposed, which is helpful to further perfect theoretical development and technological innovation of RAC durability in the aggressive environment.