Chloride ion diffusion performance of concrete and its influence on scour resistance

Abstract

Hydraulic structures are affected by many factors, and chloride ions can significantly reduce the service life of concrete. In this paper, the erosion test of chloride ion erosion is studied, the damage characterization is carried out by two-dimensional and three-dimensional characterization methods, and the numerical simulation analysis is carried out. The results show that when the water cement ratio (w/c) is 0.3, 0.4 and 0.5, the grinding depth of concrete surface reaches 21 mm, and the chloride ion concentration is stable. With the increase of w/c, the porosity increases, especially the harmful pores have the greatest influence on ion erosion. Chloride ion erosion reduces the scour resistance of concrete. When the w/c decreases from 0.5 to 0.4, the influence of ions on the scour resistance of concrete is weakened by 5.3%. Under 0.5 w/c, the exposed area of aggregate on the surface of concrete increases by 15.6%, and the average erosion rate of concrete decreases by 3.3%, 5.0% and 16.0%. With the increase of chloride ion diffusion depth, the chloride ion concentration is in good agreement with the simulated value. The interfacial transition zone around the coarse aggregate promotes ion diffusion, so that the ion concentration of the concrete surface reaches the peak. Concrete with a w/c of 0.3 has a longer life under the same conditions.