Prediction of Interfacial Bond Failure of FRP–Concrete Surface

The use of fiber-reinforced polymer (FRP) for strengthening concrete structures has grown remarkably during the past few years. In spite of exhibiting superior properties, the safety of usage is questionable as FRP undergoes brittle debonding failure. The aim of this study is to review and compare the existing research on bond failure between FRP and concrete substrates. Among the different failure modes, there has been little research in terms of intermediate crack-induced interfacial debonding and fewer strength models are developed for predicting such failures. Conducting a simple shear test on the FRP bonded to a concrete substrate can simulate this type of failure mode. Twelve specimens were tested to study the influence of concrete strength and the amount of FRP on the ultimate load capacity of a FRP–concrete bond under direct shear. Existing experimental work was collected from the literature and consists of an extensive database of 351 concrete prisms bonded to FRP and tested in direct shear tests. The analytical models from various sources are applied to this database and the results are presented.