Experimental and 3D Numerical Study on CFRP–Concrete Interface under Dynamic Loading

Static and impact laboratory tests as well as pertinent numerical simulations have been performed in this work to examine the impact of various parameters on the mechanical performance of the bonding interface between carbon fiber-reinforced polymer (CFRP) and concrete. Twelve CFRP–concrete beams were tested, and the results were used to explore the changing relationship between bonding stress and slip as well as the interfacial bonding shear stress (IBSS) and the CFRP strain. Analyses were also done on how impact velocity and CFRP length affected the interfacial bonding characteristics. The findings demonstrated that the evolution of interface failure can be separated into three stages, which are, respectively, the elastic stage, the debonding start stage, and the failure stage. The strain rate effect is demonstrated as the peak stress under dynamic loading is 2–4 times greater than that under static loading. The peak of IBSS grew during the IBSS transfer process as impact velocity increased, and it initially increased and then reduced as CFRP length increased. It was observed that the numerical outcomes based on a modified interfacial bond-slip model were in good agreement with the outcomes of the experiments. Additionally, the entire failure process of the interface can be revealed and seen in the 3D numerical simulation by adding mesoscopic non-uniformity to the modified model. The greatest relative error of interfacial stress peak between the experiment and the numerical simulation is only 12