Study on the influence of bond length on the bond properties of CFRP-concrete interface under Sulfate environment

Sulfate attack is an important factor in the degradation of CFRP-concrete interface properties. The sulfate test was simulated by the accelerated dry-wet cycle test to study the effect of interface bond length on the bond performance of CFRP-concrete interface under sulfate attack. The results show that: 1) After the dry-wet cycle of sulfate, the bond performance of CFRP-concrete interface deteriorated, and the ultimate bearing capacity, ultimate slip and bond stiffness of the CFRP-concrete decreased significantly with the increase of erosion time; 2) As the time of sulfate attack increases, the failure mode of the interface changes, the failure surface is closer to the glue layer, and the triangular shear zone is no longer generated at the loading end; 3) After the dry and wet cycle of sulfuric acid, the effective bond length of the interface increases; 4) Through the fitting analysis of the test data, the formula for calculating the effective bond length considering the influence of the dry and wet cycles of sulfate is given.