Bond behavior of CFRP reinforcement systems with concrete under static and fatigue loading

In this research, the single lap shear tests were used to investigate the bond behavior of carbon fiber reinforced polymer (CFRP) sheets bonded to concrete blocks under static and fatigue loads. The magnitude of the fatigue load was considered as a parameter that varied from a minimum load of 10% of Pu to a maximum load of 60%, 70% and 80% of the ultimate static load. For both loading scenarios, the applied load versus slips curves and the profiles of the interface zone strain were presented. In addition, comparisons, and analyses of the failure mode of samples subjected to static and fatigue loading are presented. The experimental results demonstrate that the loading level has a significant impact on the failure mode, fatigue life and stiffness degradation of CFRP-concrete joints during the fatigue loading. Finally, a prediction model for the fatigue life of the CFRP-concrete joint was developed as part of this investigation. •CFRP-concrete joints tested under static loading exhibit cohesive failure in concrete substrate.•An adhesive failure at the CFRP/adhesive interface was observed for specimens tested under fatigue loads.•The bond stiffness of CFRP-concrete joints significantly decreases in three phases as the number of loading cycles increases.•The damage factor of the bond stiffness is largely influenced by the loading level of the fatigue cycles.