氯盐干湿循环作用下表面开槽CFRP-混凝土界面抗剪性能试验

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

为探究氯盐干湿循环作用下表面开槽CFRP-混凝土界面抗剪性能,开展干湿循环(0 d、60 d和120 d)不同沟槽形状(矩形、正梯形和倒梯形)的单搭接拉伸剪切试验,研究失效模式和断裂能的变化及影响最大剪应力的因素,结合试验结果推导了考虑干湿循环的界面黏结滑移本构方程,并通过数值模拟验证其有效性。结果表明:随干湿循环进行,表面开槽法失效模式由CFRP断裂破坏转变为剥离破坏;120 d界面断裂能下降量较未开槽法减少60.04%~69.42%;正梯形组120 d最大剪应力相比其他表面开槽形状提升7.18%~9.48%。表面开槽法在氯盐干湿循环作用下具有较好的抗剪性能,建立的界面本构劣化方程适用于氯盐干湿循环作用下表面开槽CFRP-混凝土界面黏结性能的分析和模拟。

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.