干湿交替下表层混凝土中氯离子传输原理试验和模拟-硅酸盐学报.PDF

第38 卷第4 期 陈翠翠等：水泥基材料内部损伤的定量图像分析方法 · 581 · 第38 卷第4 期 硅 酸 盐 学 报 Vol. 38 ，No. 4 2 0 1 0 年 4 月 JOURNAL OF THE CHINESE CERAMIC SOCIETY April ，2010 干湿交替下表层混凝土中氯离子传输：原理、试验和模拟 李春秋，李克非 (清华大学土木工程系，北京 100084) 摘 要：在干湿交替下表层混凝土内水分的不同传输机理的基础上，建立了干湿交替下表层混凝土内氯离子传输模型。利用上游加权“预估–校正” 有限差分格式求解了对流占优的氯离子对流–扩散问题。进行了混凝土的氯离子吸附试验，并采用分段函数来表达氯离子吸附曲线。进行了为期120 d 的干湿交替下混凝土内氯离子传输试验研究。利用建立的模型和试验测得的基本材料参数进行了数值计算，计算结果同干湿交替试验中实测的氯离子 含量分布吻合较好，证明了干湿交替下表层混凝土内氯离子传输模型的正确性和考虑干湿交替过程水分本身传输的重要性。研究表明：干湿交替下混 凝土内氯离子入侵比永久浸没于氯盐溶液中的混凝土要严重得多。同时，由于混凝土对氯离子的强吸附性，干湿交替下混凝土中氯离子传输的影响深 度小于水分传输。 关键词：干湿交替；混凝土；氯离子传输；影响深度 中图分类号：O482.3 文献标志码：A 文章编号：0454–5648(2010)04–0581–09 CHLORIDE ION TRANSPORT IN COVER CONCRETE UNDER DRYING–WETTING CYCLES: THEORY, EXPERIMENT AND MODELING LI Chunqiu ，LI Kefei (Department of Civil Engineering, Tsinghua University, Beijing 100084, China) Abstract: Chloride ion transport model in cover concrete under drying–wetting cycles by taking into account different mechanisms of moisture transport in cover concrete was established. The convection–dominated convection–diffusion process was solved by finite difference method with “predictor–corrector” implicit upwind scheme. The chloride ions binding experiment was carried out and a piecewise formula was utilized to formulate the chloride ions binding capacity of concrete. The 120 d experiment of chloride transport in cover concrete under drying–wetting cycles was held. With the model and basic material parameters from the experiment, the nu- merical computation was held. The computing results of chloride content distribution in concrete are in good agreement with dr