盐渍土氯离子在混凝土中运移的耦合模型研究

通过Comsol Multiphysics模拟了盐渍土氯离子在混凝土内的运移机制。基于Fick第二定律,研究了考虑电迁移场作用、结合作用以及毛细作用的氯离子运移规律。研究表明:结合作用阻碍氯离子向混凝土内部运移,电势场和毛细作用促进氯离子向混凝土内部运移;随着氯离子向混凝土内运移,结合作用逐渐减小,初期的电场作用先增加后减小;随时间增加,结合作用与电场迁移作用减小;毛细作用仅在离子侵入初期约1.5 h内影响明显。在结构寿命期内忽略毛细作用,建立综合扩散、电场迁移及结合作用的耦合模型,预测了混凝土结构寿命,模型得到了较好的验证。

Coupling Model of Chloride Ion Migration fromSaline Soil to Concrete

The mechanism of chloride ion migrating from saline soil to concrete is simulated by Comsol Multiphysics.Based on Fick's second law,the impact of electric field,binding and capillarity are analyzed.Binding impedes the chloride ion transport;whereas electric field and capillarity promotes the transport.With the increase of invasion depth,the function of binding decreases and electric field of initial stage first increases and then decreases.The effect of binding and electric field both decrease gradually over time.Capillary action is only obvious in the initial 1.5 hours of the invasion.The coupling model in consideration of diffusion,electric field transport,and binding action was established.The model was verified by experimental data.