Bond behavior of CFRP-concrete with surface groove subjected to chloride wet-dry cycles: Experimental, strength model and design method

To investigate the effect of chloride wet-dry exposure on the bond behavior of CFRP-concrete with surface groove, firstly, four groups of single-lap tensile specimens with different groove width-to-depth ratios were designed and conducted. After the four groups of specimens were subjected to accelerated corrosion, failure modes and bond behavior were investigated. Secondly, based on two categories of failure modes, models were proposed to calculate the bond strength for fracture failure (model I) and debonding failure (model II) of the specimens, respectively. Finally, a bond design method has been proposed for CFRP-concrete with surface groove that was specifically developed for coastal environments. The results show that the failure mode of the surface groove method changes from the CFRP fracture without erosion to the CFRP sheet mixed failure and debonding failure. The bond strength of grooving method decreases along with the wet-dry cycles. The width-to-depth ratio is positively related to the average bond strength and there is an optimum value. Compared with the experimental values, the values of calculation model I are slightly higher, and the values predicted by calculation model II are within acceptable limits. These indicate that the grooving method has better bond behavior under chloride salt solution wet-dry cycles, and the proposed design method is applicable to guiding the bond design of the interface in coastal environments.