混凝土内硫酸根离子传输过程的元胞自动机模型

Cellular Automata Model of Sulfate Ion Transport in Concrete

为对硫酸盐腐蚀环境下混凝土结构耐久性进行模拟与分析.利用元胞自动机原理和硫酸根离子在混凝土中的扩散特点以及混凝土损伤演变规律,建立了用于模拟混凝土内硫酸根离子扩散过程与损伤演变的元胞自动机模型.利用该模型对硫酸盐浸泡环境下混凝土内硫酸根离子扩散过程进行了模拟,并将模型模拟结果与试验结果和Fick第二定律计算结果进行了比较.研究结果表明:元胞自动机可以用来模拟混凝土内硫酸根离子在混凝土中的传输和损伤演变过程,且精度较高;硫酸根离子浓度随侵蚀深度的增加而减小,随侵蚀时间的增加而增大;硫酸根离子沿截面深度的变化大致可分为快速减小阶段(距表面5 mm)和稳定阶段(大于5 mm);混凝土损伤度随侵蚀时间的增加而增大,随侵蚀深度的增加而减小.混凝土损伤度沿侵蚀深度的变化大致可分为完全损伤、损伤和未损伤等三个阶段;建议的模型为硫酸盐等侵蚀环境下的混凝土结构耐久性分析提供了一种新的分析方法.

To simulate and analyze the durability of concrete structure in sulfate corrosion environment.Based on the principle of cellular automata,the diffusion characteristics of sulfate ions in concrete and the evolution of concrete damage,the model of sulfate ion diffusion and damage evolution in concrete is established.The diffusion process of sulphate ions in concrete soaked by sulphate was simulated by this model.The simulation results are compared with experimental results and results calculated by Fick's second law.The results show that cellular automata can be used to accurately simulate the transfer and damage evolution process of sulfate ion in concrete.The concentration of sulfate ions decreases with the increase of erosion depth,and increases with the erosion time.The variation of sulfate ions along the cross-section depth can be roughly divided into rapid reduction stage(5 mm from the surface)and stable stage(more than 5 mm).The damage degree of concrete increases with the erosion time,and decreases with the increase of erosion depth.The change of concrete damage degree along the erosion depth can be roughly divided into complete damage stage,damage stage and undamaged stage.The model proposed in this paper provides a new method for durability analysis of concrete structures under sulfate erosion environment.