Prestressed Concrete Structures In Chloride Erosion Durability

The chloride ion eroding are the most direct,serious and universal reason leading to the corrosion of steel bar. Besides it is also an important index affecting life of prestressed concrete structure. But at present theoretical analysis and experimental research caused by chloride ion eroding at home and abroad, are launched at the premise of single factor and non stress state, it does not accord with actual working environment of concrete structure. Therefore, through fast chloride ion erosion experiment under different stress state, this article researchs on the issue of durability of prestressed concrete structure under simultaneous action of stress and chloride ion erosion.The main research contents are summarized as follows:1,Through fast chloride ion erosion experiment, chlorine ion content is gotten in concrete in different stress states and depths, and a comparative analysis is performed of the chlorine ion content under some stress states at different water-cement ratio and different stress states at some water-cement ratio. On the other, through the study on experiment dates, empirical formula for chloride ion coefficient of diffusion is obtained under drag and pressure stress states.2,According to the main ways and source penetration of chloride into concrete, mechanism of penetration of chloride into concrete and testing method for chloride ion permeability in concrete are clarified, considered some obvious limitations existed in now calculation model, mathematical model of chloride ion content is advanced varying with time and depth under different stress states, and random model of chloride ion concentration surface of steel strand on prestressed concrete structures is further put forward, and the real data of experiment are taken to validate this model.3,According to random model of chloride ion content varying with time and depth founded by considering drag and compressure stress states, chloride ion content of each layer from one to six centimetre depth are accountted in five years,ten years,fifteen years,twenty years, twenty-five year and thirty years under two special stress states, it offers a basis for further reseaching the rule of chloride ion content varying with time and depth.4,Based on the existing study of steel bar corrosion, the mechanical properties of concrete's component materials are analyzed after existing durability damage, cohesive property and flexural strength of concrete members are further reseached with improving corrosion, scientific basis is provided for durable evaluation of concrete structures.