Bond performances of FRP Rebars Reinforced Concrete

The structural performance of reinforced concrete elements is related to the interface behavior of rebars to concrete. In the last decade several research works were carried out to investigate the bond between fiber-reinforced polymer (FRP) rebars and concrete, however some aspects need further studies in order to obtain reliable design indications. In this paper the analysis of bond was performed referring to different kinds of FRP rebars and some varying influential parameters (surface treatment, kinds of fibers, and kinds of test). Results obtained show the role of the investigated parameters on bond stress law; in particular the surface treatments involve different transfer mechanisms passing from simple chemical adhesion and friction, for sanded rebars, to a relevant contribution of mechanical interlocking for deformed rebars. The kind of test utilized influences the most significant parameters of the bond stress–slip law and in different ways depending on the kind of rebars. Finally the kind of fibers causes a variation of interface stiffness. In addition a calibration of experimental bond–slip laws was performed on the basis of available theoretical models and the results are discussed