Study On Bonding Performance Between Corroded Rebar And Concrete Under Fatigue Load

Reinforcement and concrete can compose structure materials with strong bearing capacity and good integrity depend on bonding performance between reinforcement and concrete. Good bonding performance between reinforcement and concrete, not only ensure the two different materials can work in together in structure,but also is the premise of the bearing force of ordinary reinforced concrete. In practical engineering, such as carbonation, chloride ion erosion, steel corrosion in concrete structures has become a very common phenomenon. After the reinforcement corrosion, many reinforced concrete structures(such as highway bridges, crane girders, offshore platform, high-rise building, etc.) not only need to bear the effect of static load, also need to under fatigue load. Reinforcement corrosion with fatigue loading can make the bonding performance degradation, thus resulting in a decline in the ultimate bearing capacity of the component, increasing deformation, ductility and brittleness of bond failure such as the occurrence of adverse situation. The research on the rules of bond performance degradation has become very necessary. In this paper, we study on bonding performance between steel bar and reinforced concrete under concrete and fatigue load. The main research contents are as follows.(1) Through the experimental research on the bond performance between steel bar and reinforced concrete under the different corrosion rate(0%, 1%, 3%, 5%, 7%, 5%), it is obtained the degradation rule of ultimate bond strength, steel bar strain along with the change of location distribution rule and the bond stress along with the change of location distribution regularity, and is summarized the influence law of reinforcement corrosion on the bonding performance. Experimental results show that with the increase of rebar corrosion rate, ultimate bond strength in small increments first increased and then decreased rapidly, Steel strain with the location of distribution curve from the concave gradually become the convex, bond stress along with the location of the distribution curve gradually tend to be gentle.(2) Through the experimental research on the bond performance between steel bar and reinforced concrete under the different corrosion rate(0%, 1%, 3%, 5%, 7%, 5%) and under fatigue load, it is obtained the degradation rule of ultimate bond strength, steel bar strain along with the change of location distribution rule and the bond stress along with the change of location distribution regularity under reinforcement corrosion with fatigue loading, and compared the test result under the action of coupling with the test result under the single action of corrosion, some unique bonding performance degradation under the coupling action rule are summed.(3) Through the analysis of test results before, fitting out for under steel corrosion and fatigue load coupling effects of bond strength calculation formula, and explore the bonding performance degradation mechanism under coupling effect.