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通过研究裂缝混凝土中氯离子运移,建立了综合考虑扩散作用、结合作用以及电势场作用的耦合模型,预测带裂缝混凝土结构的寿命。模型从已有试验数据中得到了较好验证。基于南通盐渍土环境,运用Comsol Multiphysics软件分析了裂缝宽度和深度不同的裂缝混凝土中氯离子运移。研究表明:裂缝混凝土中氯离子浓度随侵入深度增加而降低,降低趋缓,随着时间增加而增长,增长趋缓。氯离子从混凝土裂缝运移到混凝土中时,浓度突降。随着裂缝宽度或深度的增大,氯离子含量增加,增加趋缓,宽度差别的影响减小,深度的不同对裂缝中氯离子的运移几乎没有影响,对临界氯离子浓度的侵入影响较大。为保证混凝土结构物100年使用年限,建议严格限制裂缝,保护层厚度采用55mm。
By studying the migration of chloride ions in the cracked concrete, a coupled model considering the effects of diffusion, bonding and electric potential is established to predict the life of the cracked concrete. The model obtained from the existing experimental data is better verified. Based on the environment of saline soil in Nantong, the chloride migration in cracked concrete with different crack width and depth was analyzed by Comsol Multiphysics software. The results show that the concentration of chloride ion in the cracked concrete decreases with the increase of invasion depth, decreases slowly, increases with time, and slows down. When chloride ions migrate from concrete to concrete, the concentration drops abruptly. With the increase of crack width or depth, the content of chloride ion increases, the increase slows down, and the influence of width difference decreases. The difference of depth has little effect on the migration of chloride ion in the fracture, and affects the intrusion of critical chloride ion concentration more Big. In order to ensure the useful life of concrete structures 100 years, it is recommended to strictly limit the cracks, protective layer thickness of 55mm.