Performances, challenges and opportunities in strengthening reinforced concrete structures by using FRPs – A state-of-the-art review

Abstract Structures are often subjected to extreme loading conditions that lead to their premature deterioration, and replacement of those structures before the end of their design lives is very expensive. The rehabilitation of deteriorated structures by using externally bonded fibre-reinforced polymer (FRP) composites is gaining popularity in the construction sector owing to its high strength, optimum durability and compatibility with concrete structures during application. This paper aims to review the current state-of-the-art on the performances, challenges and future opportunities of FRP-strengthened reinforced concrete (RC) structures under different loading scenarios. FRP strengthening leads to satisfactory performances under static, dynamic and extreme environmental conditions. Debonding and FRP rupture are the common types of failure observed, however, the failure mechanisms operating under the combined action of service loads and environmental exposures are still unclear. The acceptance and application of FRPs in strengthening RC structures will further increase upon developing techniques for utilising the full FRP strength, reducing the brittleness, risk of fires and accidental damage, minimising the energy consumption as well as carbon emission during production, and reducing the high initial cost. This paper also identifies the gaps in the present state of knowledge and the potential research directions for FRP-strengthened structures that lead to better understanding and establishment of design guidelines.