耦合锈蚀钢筋与混凝土间黏结性能试验研究OA

To investigate bond behavior degradation induced by combined corrosion and interaction(i.e.,coupled corrosion)of longitudinal rebars and stirrups in existing concrete structures,43 eccentric pull-out specimens were fabricated.Parameters considered included corrosion ratios(individual and coupled corrosion of longitudinal rebar and stirrup),the ratio of cover thickness to rebar diameter(c/d),and the number of stirrups.Accelerated corrosion tests and pull-out tests were sequentially conducted on these specimens.The influence of each parameter on corrosion phenomena,loading response,and interfacial bond-slip mechanisms was systematically studied.The results indicate that increasing the number of stirrups or decreasing the c/d delays cover splitting,thus enhancing bond strength and corresponding peak slip.Under slight corrosion conditions(corrosion ratios less than 1.5%for longitudinal rebar and 3.2%for stirrup),bond strength decreased by approximately 7.2%in 46%of the specimens,and increased by about 3.5%in the remaining 54%.However,as corrosion progressed,bond strength decreased gradually.The degradation in bond strength caused by stirrup corrosion,longitudinal rebar corrosion,and their coupled corrosion increased successively.Coupled corrosion involving multi-legged stirrups or larger-diameter longitudinal rebar aggravated cover cracking and thus weakened bond strength.Based on the experimental results,a continuous bond stress-slip model was developed,incorporating changes in interface constraints and coupled corrosion effects.Predictions from this model showed good agreement with the experimental results.