混凝土中氯离子传输模拟及速率分析  

Simulation and velocity analysis of chloride ion transport in concrete

作　　者：乔宏霞[1,2] 乔国斌 路承功 QIAO Hongxia;QIAO Guobin;LU Chenggong(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Western Center of Disaster Mitigation in Civil Engineering of Ministry of Education,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050 [2]兰州理工大学西部土木工程防灾减灾教育部工程研究中心,甘肃兰州730050

出　　处：《华中科技大学学报（自然科学版）》2022年第2期19-25,共7页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51168031);兰州理工大学红柳一流学科建设计划资助项目.

摘　　要：为模拟氯离子在混凝土中传输规律,基于Fick第二定律和Darcy定律建立氯离子扩散-对流模型,同时考虑温湿度、孔隙率、结合效应等多种影响因素对扩散系数进行修正,利用Matlab和COMSOL Multiphysics实现多场耦合数值模拟,最终结合试验数据模拟氯离子传输过程.结果表明:数值模拟与实验结果相关性良好,能有效表征氯离子在混凝土中的传输规律;由于水分对流速率远大于离子扩散速率,因此水分对流导致浅层出现对流区并占据主导,同时伴有浓度富集现象;随着深度加深,对流作用逐渐减弱而扩散作用占据主导,深层混凝土一直处于饱水状态并以扩散为主;浅层对流区与深层扩散区之间存在过渡区.In order to simulate the chloride ion transport in concrete,a chloride ion diffusion-convection model was established based on Fick's second law and Darcy's law.The diffusion coefficient was modified by considering various influencing factors such as temperature and humidity,porosity and binding effect.Matlab and COMSOL Multiphysics were used to realize the multi-field coupling numerical simulation,and combined with experimental data to correct the accuracy of the model.Finally,the simulation of the chloride ion transmission process is realized.The results show that after reasonable simplification,the numerical simulation has good correlation with the experimental results,and can effectively characterize the transmission law of chloride ion in concrete.Because the water convection rate is much higher than the ion diffusion rate,the water convection leads to the convection zone in the shallow layer,which is dominated by convection and accompanied by concentration enrichment.With the deepening of depth,the convection gradually weakens and the diffusion dominates,and the deep concrete is always in the state of water saturation and dominated by diffusion.There is a transition zone between shallow convection zone and deep diffusion zone.

关 键 词：混凝土 氯离子传输 离子扩散 溶液对流 数值模拟 

分 类 号：TU528[建筑科学—建筑技术科学]