Investigation on bond performance of concrete strengthened with CFRP plates

In this paper, concrete specimens with type I prefabricated cracks were prepared, and three-point bending tests were used to investigate the influence of parameters, such as carbon fiber reinforced polymer (CFRP) plate thickness, depth of the prefabricated crack, concrete strength, and loading speed, on the bonding performance of reinforced concrete structures with externally attached CFRP plates. The CCD cameras were used as the observation system, and the digital speckle technology is used to analyze the expansion characteristics of the prefabricated crack. The failure mode and crack development characteristics of the specimen are numerically simulated by finite element software. The results show that the reinforcement with externally attached CFRP plates can increase the flexural stiffness of concrete, significantly improve the flexural bearing capacity of concrete, and delay the development of cracks; under the same load, reinforcement with externally attached CFRP plates can reduce the propagation distance of prefabricated cracks and increase the bending deformation displacement of the specimen. The numerical simulation results show that, with the increase in the pasting length of the CFRP plate, the bearing capacity of the specimen gradually increases, the deformation capacity of the specimen gradually increases, and the failure crack moves from the middle to both sides.