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为了更好地理解氯离子在混凝土中的扩散机制,运用有限差分法,对混凝土圆柱在氯盐环境下服役时的氯离子扩散过程进行数值模拟,模型同时考虑了混凝土圆柱表面氯离子浓度和柱内氯离子扩散系数的时间依赖效应,得到了氯离子在混凝土圆柱截面内随时间变化的浓度分布云图。结果表明:为延长服役寿命,工程实践中可以考虑适时更换钢筋外侧的混凝土保护层,混凝土保护层的更换会产生结构内氯离子浓度的重新分布,可通过减小钢筋附近的氯离子浓度来有效延长结构服役寿命,数值模拟的结果对混凝土结构中钢筋的布筋位置具有指导意义。
In order to better understand the diffusion mechanism of chloride ion in concrete, the finite difference method is used to simulate the chloride ion diffusion process of concrete cylinder under the condition of chloride salt. The model also considers the chloride ion concentration and column The time-dependent effect of chloride ion diffusion coefficient was used to obtain the concentration distribution of chloride ions over time in the concrete cylinder cross-section. The results show that in order to prolong the service life, the replacement of concrete protective layer may result in the redistribution of chloride ion concentration in the structure, which can be effectively reduced by reducing the concentration of chloride ion near the steel bar Extend the service life of the structure, and the result of numerical simulation is instructive for the location of reinforcement in the concrete structure.