海洋环境中氯离子侵蚀作用下混凝土结构耐久性试验研究

发布时间：2018-03-03 05:02

本文选题：汕头海洋环境　切入点：钢筋混凝土结构　出处：《长沙理工大学》2013年硕士论文　论文类型：学位论文

【摘要】：沿海地区钢筋混凝土结构物在没有遭受地震等破坏性自然灾害等情况下，由于长时间在腐蚀环境下工作，服役仅十几到二十几年却已出现了不同程度的破坏现象，有些已经达到需要进行大修或拆除的程度，甚至有发生倒塌等危险情况而造成事故发生的可能。根据过往资料显示，每年由于混凝土结构失效而造成的经济损失十分严重，因此，钢筋腐蚀问题作为影响混凝土结构耐久性的第一因素日渐受到世界各国的重视。海洋环境中结构物受到的氯离子侵蚀作用十分明显，一旦引起钢筋锈蚀导致结构破坏，后果将会十分严重，因此，对于沿海地区钢筋混凝土结构耐久性的研究是很有必要的。本文结合广东省公路管理局科技项目研究，根据汕头沿海地区环境气候特点，对海洋环境中氯离子侵蚀作用下混凝土结构耐久性进行研究，有着重大的理论和实际应用意义。针对海洋环境中混凝土结构耐久性研究中存在的一些问题及不足，主要从以下几个方面研究了混凝土结构的耐久性： 1.通过了解海洋环境下氯离子侵入混凝土内部的几种机理，分析了海洋环境影响氯离子侵入速度的内外因素、引起混凝土中钢筋锈蚀的作用机理以及探讨了氯离子的扩散理论基本模型的适用性。 2.根据汕头地区的气象资料显示，汕头海洋环境对混凝土结构物的侵蚀比较严重，必须引起足够的重视。通过选取最具代表性的区域，浪溅区和盐雾大气区来进行取样，对各深度氯离子浓度进行测定，对不同服役时间，不同混凝土强度下在不同高程，相对面的混凝土结构的氯离子含量随深度的变化进行分析对比，并且通过曲线拟合，预测混凝土结构内部钢筋锈蚀时间，及时做出处理，保证结构的正常使用。 3.利用综合盐雾腐蚀箱模拟汕头地区海洋盐雾大气区环境，采用混凝土表观涂层系统和硅烷浸渍两种常用的沿海混凝土结构防腐蚀施工工艺，对不同氯离子腐蚀浓度、不同的干湿循环次数的混凝土试件进行防腐处理，得到表观防腐涂装技术在抗氯离子渗透性能方面对提高混凝土耐久性的效果，并且通过曲线拟合，可将实验室模拟实际海洋环境所得研究成果可直接用于结构设计，从而通过实验室就可以预测实际混凝土结构在使用过程中受氯离子腐蚀程度，，指导设计方案的选择。
[Abstract]:The reinforced concrete structures in coastal areas have not been subjected to destructive natural disasters such as earthquakes, because they have been working in corrosive environment for a long time, but they have been in service for only 10 to 20 years. Some have reached the point where major repairs or demolitions are required, or even accidents may occur as a result of dangerous situations such as collapses. According to past data, the economic losses caused by the failure of concrete structures are very serious every year. Therefore, as the first factor affecting the durability of concrete structures, the corrosion of steel bars has been paid more and more attention by many countries all over the world. The consequences will be very serious, so it is necessary to study the durability of reinforced concrete structures in coastal areas. The research on the durability of concrete structures under the action of chloride ion erosion in marine environment is of great theoretical and practical significance. In view of some problems and shortcomings in the study of durability of concrete structures in marine environment, The durability of concrete structure is studied from the following aspects:. 1. The internal and external factors affecting chloride intrusion velocity in the marine environment are analyzed through understanding several mechanisms of chloride ion intrusion into concrete under marine environment. The mechanism of reinforcing bar corrosion in concrete and the applicability of the basic model of chloride diffusion theory are discussed. 2. According to the meteorological data of Shantou area, the marine environment of Shantou has serious erosion of concrete structure, and it must be paid enough attention to. Sampling is carried out by selecting the most representative area, the splash area and the salt fog area. The chloride ion concentration of different depth was measured, and the chloride ion content of concrete structure with different height and different height was analyzed and compared under different service time, different concrete strength and different depth, and the change of chloride ion content of concrete structure with different depth was analyzed and compared by curve fitting. To predict the corrosion time of steel bar in concrete structure and to deal with it in time to ensure the normal use of the structure. 3. The environment of marine salt fog in Shantou area is simulated by using the comprehensive salt fog corrosion box. Two common anti-corrosion construction techniques of concrete structure, such as concrete surface coating system and silane impregnation, are used to deal with the corrosion concentration of different chlorine ions in coastal concrete structures. The concrete specimens with different dry-wet cycles were treated with anticorrosion to obtain the effect of the apparent anticorrosive coating technology on improving the durability of concrete in the aspects of resistance to chloride ion permeation. The results obtained from the laboratory simulation of the actual marine environment can be directly used in the structural design, so that the degree of chloride corrosion of the actual concrete structure can be predicted through the laboratory, and the selection of the design scheme can be guided.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU375

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