混凝土内氯离子扩散影响因素的研究综述

Review of Research on the Influencing Factors of Chloride Ion Diffusion in Concrete

随着建筑行业的迅速发展,钢筋混凝土结构得到了广泛应用。但钢筋混凝土结构长期处在氯盐环境中易发生钢筋腐蚀现象,从而降低结构的耐久性。因此,全面系统地认识混凝土内氯离子扩散的影响有助于解决结构氯盐侵蚀问题。氯离子在混凝土中的传输机制极其复杂,其中扩散是氯离子传输的主要机制。文章梳理了国内外近年来关于混凝土内氯离子扩散的研究进展,重点评述了混凝土内氯离子扩散的影响因素,笔者认为低水灰比、加入掺和料、适当增加保护层厚度、限制裂缝宽度等基本措施可以有效减缓钢筋腐蚀。若结构处于恶劣环境中,在采取基本措施的基础上,还需要进一步采取附加措施,主要包括添加缓蚀剂、进行表面涂层、电化学处理等。这些措施得到了一系列的理论及试验验证,为工程应用提供了可行性参考。

With the rapid development of the construction industry,reinforced concrete structures have been widely used.However,reinforced concrete structure is prone to corrosion of steel bars in the chloride environment for a long time,thereby reducing the durability of the structure.Therefore,a comprehensive and systematic understanding of the effect of chloride ion diffusion in concrete can help solve the problem of chloride salt erosion of structures.The transmission mechanism of chloride ions in concrete is extremely complicated,and diffusion is the main mechanism of chloride ion transmission.The article summarizes the research progress on the chloride ion diffusion and reviews its influencing factors in concrete in recent years at home and abroad.It is indicate that some basic measures by decreasing water-cement ratio,adding admixtures,appro-priately increasing the thickness of the protective layer,and limiting the width of cracks can effectively slow down the corrosion of steel bars.To protect the reinforced structure in a harsh environment,these measurements must be supplementary by others such as the addition of corrosion inhibitors,surface coating,and electrochemical treatment,etc.These supplementary measurements have been verified by a series of theories and experiments,which provide a feasible reference for engineering applications.