硫酸盐作用下混凝土中氯离子传输的数值模拟

Numerical Simulation of Transport Process of Chloride in Concrete under the Action of Sulfate

对硫酸盐作用下混凝土中Cl-的扩散规律进行了室内模拟试验研究。溶液采用1mol/L氯化钠溶液,以及分别加入0.1mol/L,0.3mol/L和1mol/L硫酸钠的复合溶液,并以清水溶液作为对比。结合试验参数,基于Fick扩散定律,利用ANSYS软件对混凝土中氯离子等效扩散系数进行了数值分析和计算。结果表明,在试验时间范围内,氯离子的等效扩散系数随时间呈指数递减规律;当溶液中的硫酸根浓度由0增加到0.3mol/L时,氯离子扩散逐渐增强;当硫酸根浓度为1mol/L时,氯离子扩散明显减弱。对试验结果进行数据拟合后,建立了混凝土中氯离子等效扩散系数与时间、硫酸根离子边界浓度的关系表达式,所建立的表达式可用于硫酸盐及氯盐共同侵蚀下混凝土内部氯离子浓度的预测。

The diffusion law of Cl-in common concrete containing SO42-was studied.0.1mol/L,0.3mol/L and1mol/L sodium sulfate were added,respectively,in 1mol/L sodium chloride as composite solution,and clean water was taken as contrast.According to the experimental parameters and the Fick diffusion law,the diffusion coefficient of chloride ion in concrete was analyzed and numerically calculated using ANSYS software.The results showed that,in the experimental range,the equivalent of chloride ion diffusion coefficient exponentially decreased with time;when the sulfate concentration in solution increased from 0to 0.3mol/L,the chloride ion diffusion increased gradually,when the sulfate concentration was 1 mol/L,the chloride ion diffusion decreased.The expression showing the relationship between chloride ion equivalent diffusion coefficient,diffusion time and boundary concentration of sulfate ion was established after the experimental results data were fitted.The expression can be used to predict the concentration of the internal concrete chloride ion in this type of environment.