自然扩散法预测感潮环境下混凝土氯离子侵蚀  

Erosion Prediction of Chloride Ions in Existing Concrete under the Natural Tidal Environment by the Natural Diffusion Method

作　　者：张俊芝[1] 郑辉[1] 周建民[1] 王梁英[1] 刘华挺[1] 

机构地区：[1]浙江工业大学建筑工程学院,浙江杭州310014

出　　处：《建筑材料学报》2011年第2期164-168,179,共6页Journal of Building Materials

基　　金：国家自然科学基金资助项目(50879079)

摘　　要：通过对自然感潮环境下混凝土的自由氯离子浓度分布的分析,研究了既有混凝土氯离子侵蚀的特征及扩散特性,采用室内自然扩散法进行了模拟扩散试验,并根据Fick第二定律和MonteCarlo法分析了既有混凝土和试验混凝土的扩散参数及钢筋初始锈蚀时间.结果表明:自然环境下混凝土的氯离子侵蚀存在明显的对流区,自然扩散法的氯离子扩散系数大于自然环境下2个数量级,模拟混凝土中钢筋表面的自由氯离子浓度是自然环境下实际浓度的2倍,钢筋初始锈蚀时间是实际的240倍.Characteristics of erosion and diffusion of free chloride ions in existing concrete are studied through analysis for chloride ion concentration distribution of concrete in the natural tidal environment,a simulation experiment for chloride ion diffusion by the indoor natural diffusion method is tested,diffusion parameters and the initial corrosion time of steel bar in concrete of existing concrete and experimental concrete are analyzed on the basis of Fick＇s second law and the Monte Carlo method.The experimental and analysis results show that there are obvious convective region of chloride ion ingress in the natural environment,the chloride diffusion coefficient measured by the natural diffusion method is two orders of magnitude larger than that in the natural tidal environment,and free chloride ion concentration of reinforcement surface in simulated concrete is double of actual concentration of concrete in the natural tidal environment,initial time of corrosion of steel bar in experimental concrete is 240 times higher than concrete in the natural environment.

关 键 词：既有混凝土 氯离子 自然扩散法 初始锈蚀时间 预测 

分 类 号：TU528.01[建筑科学—建筑技术科学]