Mechanical behavior and durability of coral aggregate concrete and bonding performance with fiber-reinforced polymer (FRP) bars: A critical review

Abstract

Utilization of coral aggregates (CAs) for concrete production can effectively resolve the shortage of raw materials for construction in remote islands and reduce the energy consumption due to the shipping from the mainland. However, the porous nature of CAs and contained salt will affect the mechanical and durability performance of the concrete. This study aims to first summarize the characteristics of CAs and properties of coral aggregate concrete (CAC) and then propose future research needs based on the identified knowledge gaps. The previous studies indicate that the utilization of CAs in concrete can lead to significant strength loss and the elastic modulus of CAC is generally lower than that of ordinary concrete (OC). The workability of concrete at the fresh stage can also be reduced by the added porous CAs. To resolve these issues, the pre-treatment protocols were proposed to enhance the performance of CAC, including acid washing, surface coating, and utilization of alternative cementitious materials. However, the influence of CAs on the durability performance of concrete has not been fully understood, including drying shrinkage and carbonation resistance. The corrosion issue is also a serious threat to the durability performance of reinforced CAC. It is expected that using the non-corrosive fiber-reinforced polymer (FRP) bars can effectively resolve the corrosion issues, but the related investigations are quite limited. The research needs on the durability performance of CAC and the evaluation of FRP bars reinforced CAC are then proposed for further investigation. This study can serve as a solid base for future investigation on CAC and promote its application in ocean engineering. • The effects of coral aggregates on the properties of concrete are discussed. • Many effective measures to improve the performance of coral aggregate concrete are summarized. • The combination of fiber reinforced polymer bars and coral aggregate concrete is attractive.