A generic non-linear bond-slip model for CFRP composites bonded to concrete substrate using EBR and EBROG techniques

In this study, a generic bond-slip model is proposed for carbon fiber reinforced polymer (CFRP) reinforcement bonded to concrete substrate. The model is applicable to concrete members strengthened by the conventional externally bonded reinforcement (EBR) technique, as well as to those members strengthened using the recently introduced externally bonded reinforcement on grooves (EBROG) method. The model was first calibrated using 39 single lap-shear tests performed on EBR and EBROG joints having various concrete strength, CFRP thickness, and groove depth (in case of EBROG joints). Afterwards, the excellent performance of the model in terms of its high prediction accuracy of the bond-slip behavior and ultimate capacity of EBR and EBROG joints was verified using a set of independent experimental data collected from the existing literature. Owing to the certain advantages of the proposed model including its high accuracy and applicability to predict the bond behavior and strength of both EBR and EBROG joints, the proposed model can be an efficient alternative to the existing ones for predicting the CFRP-to-concrete bond behavior. Furthermore, single lap-shear tests performed on CFRP strips bonded to concrete substrates demonstrated that the interfacial fracture energy of EBROG joints is almost three times that of the EBR joints.