Simulation Of Crack Development In Concrete Protective Layer And Reinforcement Analysis Based On Corrosion Expansion Force

When the steel corrodes, the volume of rust is larger than the original. It exerts pressure on the concrete around the rebar and then the cover of concrete will crack. The corrosion would be accelerated once the crack happen , as a result of it , the speed of crack will accelerate, which result in destroy of structures and affect the durability of concrete structures. So it has important research significance to analyze the crack process of the concrete cover due to corrosion and repair measures. Based on the existing research, the main work of this paper can be summarized as follows:1. The paper study the electrochemical principle of reinforcement corrosion and the main affecting factors. The process of breaking down of reinforced concrete is discussed. The measure of how to prevent steel corrosion in concrete structure and how to repair damage structure is mentioned.2. Based on the theory of uniform corrosion expansion, the method for calculating the force when the crack come through the protective layer was established. A FEM software FINAL is used to establish model to simulate the progress of breaking down though adding load step by step. Obtain the development chart from the initial cracking to the failure and the maximum principal stress chart.3. The method of varying parameters is used in this paper to analysis the influence on crack development when protective layer thickness and concrete strength is changed. Based on the result of numerical simulation of crack development, the conclusion that the ability to resist corrosion of reinforced concrete structure is enhanced when increase the thickness of protective layer or improve the concrete grade can be obtained. Increase the thickness of protective layer has no affect on increasing the initial cracking load while increase the strength of concrete will delay the moment of crack happens.4. Reinforcement model of concrete has been established. Take the model that is not reinforced and the reinforced model to compare with the reinforced model that has corrosion damage. Analysis the crack propagation and the stress distribution and the load corresponding to typical crack state of three models. Based on comparative analysis of images and values, The conclusion that paste the reinforced concrete board at the protective layer can improve the ability to resistance corrosion expansion of concrete structure and its durability.