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

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. (c) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Utilization of coral aggregates in concrete production can solve raw material shortages in remote islands, but issues such as strength loss and durability performance need further research. Proposed solutions include pre-treatment protocols and utilization of non-corrosive FRP bars to improve the performance of coral aggregate concrete. Further investigation on durability performance and FRP bars reinforced CAC is needed to promote its application in ocean engineering.