Behaviour Of Corrosion Fatigue Damage Of Bond Behaviors Between Steel Strand And Concrete

Many prestressed concrete structures need to bare the combined effect of fatigue loads and corrosive environments, which will lead to non-convergence fatigue and corrosion coupling damage of steel and concrete bond interface and structural resistance degradation continuously.In this paper,the corrosion fatigue damage characteristics and evolution of the steel strand and concrete bonding are studied based on long-term corrosion fatigue damage test simulates under chloride corrosion environment, so as to provide a reference for durability assessment and design of prestressed concrete structure.The fatigue loading tests of corroded prestressed concrete bond specimens mixed with salt were conducted, then these specimens were pulled out. Damage characteristics of steel strand and concrete were analyzed. Trends of ultimate bond stress with the number of fatigue and mixed salt rate,and characteristics of bond-slip curve were get by servo tester and strain tester.By using the method of constant current to accelerate the corrosion rate of steel strand, while being conducted fatigue loading on the bond specimens,corrosion fatigue damage characteristics of bond and the law of the influence of corrosion on the fatigue life are studied.Concrete splitting and strand pulling out occur in the test while the specimen bare corrosion and fatigue effect, then the fatigue life ends. Bond fatigue life varies with the fatigue stress amplitude and corrosion fatigue strength factor which showed exponential decline;fatigue life prediction model of bond specimen is established with fatigue stress amplitude and corrosion fatigue strength factor by fitting the experimental results.According to the results of previous studies, compared the degradation and model of both tensile properties of steel strand and the bond properties of concrete, it was found that tensile properties of steel strand is decisive factor under the combined effect of corrosion and fatigue, the bond properties of steel and concrete is relatively to become the second.