Bond behaviour between NSM CFRP laminate and concrete using modified cement-based adhesive

Near-surface mounted (NSM) techniques have been successfully utilized for the strengthening of concrete structures with CFRP composites. Although the adhesive most commonly used for strengthening of structures is epoxy, this adhesive is suitable only for low temperature environments due to the deterioration of its mechanical properties at elevated temperatures, in addition to its other disadvantages such as flammability and emission of toxic fumes. Substituting the epoxy with cementitious adhesive is therefore of great interest. However, few investigations on the strengthening of concrete structures using cementitious bonding materials have been reported, particularly for NSM CFRP strengthening systems. Since the bond between NSM FRP reinforcement and the concrete substrate plays a major role in the efficiency of NSM strengthening systems, in this paper, the bond properties of NSM CFRP laminate using modified cement-based adhesive are investigated. 15 concrete specimens were studied, and parameters including bond length, strain distribution, and bond-slip curve were considered. Finite element simulation was conducted to verify the experimental results using ATENA Software from Cervenka. The results showed excellent bond properties with reasonable correlation between experimental and finite element analysis results.