干湿循环下混凝土中氯离子的一些扩散特性  

Diffusion characteristics of chloride ions in concrete under cyclic wetting-drying

作　　者：陈春雷[1] 邵林[1] 郑建军[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：《混凝土》2009年第3期21-23,共3页Concrete

基　　金：国家自然科学基金项目(50878196);浙江省自然科学基金项目(Y107638)

摘　　要：研究了干湿循环下混凝土中氯离子的一些扩散特性。根据浙江沿海的气候特点,提出了干湿循环下混凝土氯离子扩散试验方案,并测定了自然循环和加速循环下混凝土中各点氯离子浓度随时间的变化。试验结果表明:对于给定的暴露时间,混凝土中的氯离子浓度随着离混凝土表面距离的增大而减小;对于混凝土内部任一给定点,氯离子浓度随着暴露时间的增长而增大;对于给定的暴露时间和混凝土中给定点,加速循环下的氯离子浓度高于自然循环下的氯离子浓度。利用Fick方程解和最小二乘法,给出了混凝土氯离子扩散系数与暴露时间之间的关系。发现混凝土氯离子扩散系数随暴露时间的增长而减小,与干湿循环几乎无关。Some diffusion characteristics of chloride ions in concrete under cyclic wetting-drying are studied.According to the characteristics of Zhejiang coastal climate, an experimental scheme is designed for the diffusion of chloride ions in concrete under cyclic wetting-drying and the changes of the chloride ion concentration at any point in concrete with time are measured under natural and acceleration cycles.Experimental re- suits show that the chloride ion concentration decreases with the distance fi-om the concrete surface at a given time and increases with time at a given point in concrete.It is also demonstrated that the chloride ion concentration under acceleration cycle is larger than that under natural cycle for a given time and point in concrete.Based on the solution to Fick＇s equation and the method of least squares, the relationship between the chloride diffusivity of concrete and exposed time is given.It is found that the chloride diffusivity of concrete decreases with exposed time but is almost independent of cyclic wetting-drying.

关 键 词：干湿循环 混凝土 氯离子扩散系数 氯离子浓度 

分 类 号：TU528.01[建筑科学—建筑技术科学]