| Reinforcement corrosion caused by carbonation or chlorides has been recognized as a major disaster of concrete bridges. At present, the durability evaluation and residual fatigue life prediction of concrete bridges are badly needed in China. Generally, the failure of reinforced concrete members is the fatigue fracture of corroded steel bars.In order to predict scientifically and extend properly the service life of aged existing reinforced concrete bridges, based on the Shang dong Province Young and Middle-Aged Scientists Research Awards Fund (No. BS2011SF013) and the National Natural Science Foundation of China (No.51008182), considering the corrosion ratio and stress amplitude, fatigue behavior of natural corrosion reinforcement and naked corrosion reinforcement was investigated by axial tensile fatigue tests of corroded specimens.The fatigue curves of natural corrosion reinforcement and naked corrosion reinforcement were established respectively by statistical regression analysis. The fatigue deterioration laws of natural corrosion reinforcement and naked corrosion reinforcement were analyzed. The suggested values of the allowable stress amplitude corresponding to different target fatigue lives under the50%ensuring probability were proposed for natural corrosion reinforcement and naked corrosion reinforcement. Finally, the difference of natural corrosion, naked corrosion and accelerated corrosion on the fatigue life of reinforcement are discussed.The study results indicate that the fatigue life of corroded reinforcement is mainly affected by corrosion rate; the relationship between stress amplitude and fatigue life on a logarithmic scale for natural corrosion reinforcement and naked corrosion reinforcement shows linear as no corrosion ones. However, a significant reduction of the fatigue life of corroded reinforcement with the appearance and development of corrosion. It can provide references for durability evaluation and residual life of corroded reinforced concrete bridges. |
