Interfacial Performance between CFRP and Concrete based on PZT-based Monitoring

The bonding interface between CFRP and concrete is the key link for load transfer in externally strengthened concrete structures. However, there lacks no effective monitoring method for the performance of the interface under mechanical loading and environmental conditions. This paper applies piezoelectric transducers (PZTs) to monitor the interface performance and studies the bond degradation of the interface under various working conditions. The main research contents and conclusions are as follows: (1) CFRP-concrete interfaces were subjected to wetting-drying cycling, field conditioning and low-cycle fatigue followed by wetting-drying cycling, and the single shear tests were performed to explore the variations in the interfacial performance. It can be found that these working conditions lead to failure mode converted from cohesive failure to a mixed mode of cohesive and adhesive failure and changes in the bond parameters. (2) An electromechanical impedance method using PZTs is found to be capable of monitoring the interface damage evolution during shear tests. The damage index was extracted from the obtained electromechanical impedance responses. The correlation between the damage index and bond parameters was performed, revealing the negative correlation between the damage index and local bond strength.