Study On Corrosion Experiment Of RC Bending Members Under Chloride Enviroment In The Tidal Zone

The durability of concrete structures is one of the important issues which draw the public concern in the field of engineering. Chloride ion penetration is one of the important factors to influence the durability of RC members. The penetration of chloride ion into concrete will make steel bars rust, and reduce carrying capacity of RC member which can lead to the degradation of safty and durability of the engineering structures. The impact of chloride ingression with bending load is much obvious. The study of durability failure problem of concrete structure caused by flexural loading and chloride ion has an important significance.On the basis of present research and based on the background of chlorine ion erosion environment in the costal tidal zone, a series of field exposure experiments and laboratory simulation tests are designed and completed in this paper. Based on the means of experimental research and theoretical analysis, the results of experiments under two environment are analyzed in the aspect of simulation. The main contents and achievement in this paper are summarized as follows:1. Under the condition of chlorine ion erosion environment in the costal tidal zone, a series of RC members field exposure experiments is carried out and fulfilled. According to results of the field exposure experiments, the influence factors of bending loads on the chloride ingression parameters, including peak concentration and the depth of convection area and diffusion coefficient are analysez.2. By simulating the environmental factors of chlorine ion erosion environment in the costal tidal zone, a serial of laboratory simulation tests about chloride ion erosion of reinforced concrete bending members are designed and completed. In the laboratory simulation environment, the impact of water cement ratio, erosional time and flexural loading on the main chloride ingression parameters involving diffusion coefficients at the compressed zone and tensile zone of the concrete are concluded in this paper. The influence of the corrosion rate of reinforcement caused by bending load to the mechanical properties of corroded steel bar and the carrying capacity of RC beams are studied at the same time.3. Using the classic similarity theories, the similarity of environment between the field tests and laboratory simulation tests is analyzed. According to the comparative analysis of the results obtained from the field tests and laboratory simulation tests, the similarity criterion equations under two sorts of experimental environment are researched which criterion equations include the peak concentration, the depths of convection area, the diffusion coefficients, and the similarity criterion equation describing the process of chloride ion corrosion under flexural loading. The results show that a part of parameters in laboratory simulation tests are similar with parameters in field test.