Investigation of Bond Behavior between Steel Bar and Concrete under Coupled Effect of Fatigue Loading and Corrosion

Abstract

The bond performance between concrete and steel bars in complex environments forms the basis for the serviceability and safety of RC (reinforced concrete) structures. To investigate the bond behavior between steel bars and concrete under different conditions, a series of pullout tests were conducted. Corrosion and fatigue loading were selected as influencing factors for the degradation of bond behavior, and a series of tests were developed to investigate the corrosion level, surface crack width, failure mode, strain distribution, bond stress, slip under a single effect (fatigue, corrosion), and the coupled effect of corrosion and fatigue loading. The test results indicate that the corrosion level and surface crack width increase with increasing fatigue cycles, fatigue loading has little impact on the bond stress and slip, and chloride penetration exhibits a significant influence on the decrease in peak bond stress and increase in slip. A comparison with the specimens experiencing a single effect indicated that the coupled effect of fatigue loading and corrosion accelerated the degradation process of the bond performance and that the dominant factor of the degradation process transformed from fatigue loading to corrosion with increasing coupled effect time. Considering the nonuniform corrosion morphology of steel bars, a prediction model for bond strength is established based on the single trigonometric series method and minimum potential energy principle. Through evaluation of the experimental data, a model for the bond stress-slip relationship under the coupled effect of fatigue and chloride penetration is proposed.