Research The Durability And Life Of Concrete Under The Action Of Load And Salt Solution Coupling

The durability degeneration of concrete will not only shorten the service lifetime of concrete structures but also reduce the safety and reliability of engineering structures. Especially the process of sulfate attacking concrete is a complex phenomenon which involves effects of physics, chemistry and mechanics, it is affected by many factors, its harm is very great, it is one of the important content of concrete durability research.In practice, its mechanism is more complex when the concrete suffer from couple effects of loading, single or double sulfate attack. Therefore, it is a matter of great theoretical significance and application value for improving the safety on the design of concrete structures and predicting the service lifetime of concrete structures to study the durability of concrete under the loading, single or double sulfate attack. At the same time, the comprehensive evaluation of concrete durability in terms of sulfate ion diffusion provides the basis of the theoretical foundation for design of concrete durability in sulfate environment. Therefore, the context studies the damage of concrete under couple effects of sulfate, chloride and flexural loading, also it carries out diffusion regularity of numerical analysis under the action of sulfate erosion, and finally it establishes lifetime prediction model. The main research work is as the following:(1) Firstly the experiment studies the damage evolution law of the Concrete under the effect of single factor (sulfate), double factors (sulfate, chloride), three factors (sulfate, chloride and flexural loading), analyzes Ed’s change law under the action of different factors and the influence law of Erd under the complex factors. Erd is made use of establishing the concrete damage failure evolution equation when mechanical factors, environmental factors and the types of concrete are taken into account.(2)Secondly the experiment studies reinforcement corrosion law and the law of damage evolution on reinforced concrete under the effect of sulfate, chloride and loading. It also analyzes that the corrosion potential and corrosion current density will change under different factors as time goes on and they will also change by the different water cement ratio of concrete and flexural loading rate. Ed of reinforced concrete will delay under compressive stress injury, while tensile stress will accelerate damage process, but the existence of the flexural loading will not change the damage law of concrete.(3)Thirdly the experiment studies the distribution regularity of ion diffusion on the concrete in complex solution. It mainly studies the distribution regularity of sulfate ion on concrete under different w/c in sulfate solution considering the existence of chlorine ion in complex solution influenced on the distribution regularity of sulfate ion diffusion. Also it studies the distribution regularity of the free chloride ion and the total chloride ion in chloride solution under different w/c of concrete considering the distribution regularity of the free chloride ion and the total chloride ion diffusion influenced by the existence of sulfate ion in complex solution.(4)Finally it studies the diffusion model of sulfate ion in the concrete, and establishes the life prediction of concrete through this model. It not only establishes the law that sulfate ion diffusion coefficient decays as time goes on, but also establishes the relationship between diffusion coefficient of sulfate ion and Erd of concrete damage.Besides, it also establishes the chloride ion binding ability of sulfate ion diffusion coefficient of correction.