Experimental study on interfacial shear behavior of CFRP-concrete with surface groove subjected to chloride wet-dry cycles

Abstract:

To investigate the shear behaviour of CFRP-concrete with surface groove subjected to chloride wet-dry cycles, single-lap tensile shear tests with different groove shapes (rectanglular, trapezoidal and inverted trapezoidal) were carried out for 0 d, 60 d and 120 d wet-dry cycles. The changes in failure mode, fracture engergy and factors influencing the maximum shear stress were examined. On the basis of experimental results, we derived the bond slip constitutive model considering dry-wet cycles and its effectiveness was validated through numerical simulations. The results show that the failure mode of the surface groove method transitions from the CFRP sheet fracture without erosion to the mixed failure and debonding failure of the CFRP sheet. Compared with EBR specimens, the interface fracture energy of 120 d wet-dry cycles reduces by 60.04%-69.42%. The maximum shear stress of the trapezoidal groove after 120 d wet-dry cycles is increased by 7.18%-9.48% compared with other surface-grooved shapes. These results indicate that the surface groove method exhibits superior shear behaviour under wet-dry cycles. The developed deterioration formula of the interface constitutive relationship is applicable for analyzing and simulating the interfacial bond behaviour of CFRP-concrete with surface groove under wet-dry cycles.