The Chloride Ion Erosion Of RC Members Under Flexural Loads And The Similarity Of Simulation Test In Tidal Range

The chloride erosion in environmental water leads to corrosion of the reinforcement in the RC structures in the service process, and the RC structures will happen failure before the design durability life. The bending load effect of the RC structure in service process will produce micro cracks in tensile concrete, and accelerate chloride erosion, and reduce the bearing capacity of beam component, which will influence the durability life of RC structure.In this paper, based on the present study, the chloride ingress test of longer exposure time in concrete under the natural tidal range environment and the dry-wet cycling environment of artificial simulation were designed and accomplished. The influences of exposure time, bending loads and water-cement ratio on the chloridle diffusivity were studied. The bearing capacity of RC beams, corrosion and mechanical properties of stressing bars and those variability were discussed. Based on the similarity theory, the similarity of the main parameters of chloride erosion and time-varying similarity under different exposure conditions were studied. According to the fitted theoretical model, the initial corrosion time of steel bars in RC beams and the similarity under different exposure conditions were calculated. The main contents in this paper are as follows:1. According to erosion test under the natural tidal range environment, resistance of RC beam in bending to chloride ion erosion which exposure time of the longest 780d is studied. The effects of exposure time, bending load level and water-cement ratio on the concentration of free chloride ion and chloride diffusion in concrete were analyzed.2. Based on erosion test under the dry-wet cycling environment of artificial simulation, the resistance of the RC beam in bending to chloride erosion after the longest exposure 280d was studied. The effects of exposure time, bending load level and water-cement ratio on distribution of free chloride concentration and chloride ion diffusion in concrete were analyzed.3. The bearing capacity and mechanical properties and those variability of RC beams in bending under two kinds exposure conditions are studied. The effects of exposure time, bending load level and water cement ratio on the failure characteristics and the corrosion rate of steel bar of RC beams were analyzed.4. Based on the classical similarity theory and the experimental results, the time variation and time-varying similarity of chloride ion diffusion coefficients and the peak values of free chloride ion concentration in concrete of RC beams under different tidal environments were analyzed. The similarity and the time-variation law of the corrosion rate of the steel bar in the test beams are studied, and the initial corrosion time of bars in RC beams under different exposure conditions were predicted, and the similarity of initial corrosion time of bars under two tidal environments were also analyzed.