Numerical Simulation Investigation of the Effect of Crack Width and Depth on Chloride Diffusion in Pipe Pile Concrete

PHC pipe piles are widely used in engineering construction due to their high bearing capacity and adaptability. However, the presence of cracks in the pipe body accelerates the corrosion process of chloride ions on pre-stressing steel reinforcement, especially in the marine environment. In this paper, the effect of crack width and depth on the diffusion behaviour of chloride ions in pipe pile concrete is deeply analysed by numerical simulation method for the durability of pipe pile concrete under cracking conditions. A theoretical model of chloride diffusion based on Fick's law was established, and a fine structure model of PHC pipe pile concrete was constructed to determine the material parameters in the model. The simulation results reveal that both crack width and depth have an effect on the chloride diffusion rate, with the increase in crack depth having a more significant effect on chloride diffusion. In addition, the study emphasizes the critical role of the concrete protective layer thickness in slowing down the chloride diffusion and improving the durability of the pipe piles. The conclusions of this paper provide theoretical basis and technical support for the durability design and maintenance of PHC pipe piles, and provide new perspectives and methods for the durability enhancement of concrete structures in practical engineering.