A review of test methods for studying the FRP-concrete interfacial bond behavior

Due to aging of existing structures and/or change of expected load patterns and their magnitudes, their strengthening becomes a necessity. The application of externally bonded fibre-reinforced polymer (FRP) for this purpose has gained popularity, among other methods, due to its simplicity and convenience. However, the full capacity of FRP strengthening system is sometimes undermined by the premature failure of the bond between FRP and the substrate. Consequently, many works are available in the literature that focus on studying the FRP-concrete bond strength. This paper presents a review of the existing experimental tests on the bond between FRP and concrete. The major approaches and their variations as implemented by various researchers are presented and discussed, followed by a section on the data acquisition systems. The pros and cons of each of the test methods are presented followed by some perspectives and the need for future research. Finally, a new testing configuration is proposed for the double shear lap test and its associated advantages over the conventional approach are discussed.