考虑钢筋阻滞效应的混凝土构件氯离子扩散试验及耐久性研究

发布时间：2018-02-10 05:45

本文关键词： 海洋环境混凝土氯离子扩散钢筋阻滞效应耐久性　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：钢筋混凝土结构广泛应用于港口、海岸及近海工程中,多年使用经验表明,由海洋环境中的氯离子引起的结构耐久性破坏已经成为其设计与维护中面临的一个十分严重的问题。虽然国内外学者对该问题已经开展了很多的研究,但由于其问题十分复杂,很多研究还不完善。针对氯离子侵蚀的研究,目前得到的氯离子扩散模型大都忽略了钢筋存在的阻滞影响以及钢筋前沿至混凝土表面这一浅层混凝土区域氯离子扩散的特殊性。本文着眼于耐久性破坏的第一阶段氯离子侵蚀,在总结前人研究的基础上,通过试验及有限元分析的方法对钢筋存在的阻滞效应以及钢筋前沿至混凝土表面这一浅层混凝土区域氯离子扩散的特殊性做了一些探索。主要研究内容如下:(1)对前人大量的氯离子侵蚀机理研究成果进行整合、对比、分析,明确各机理模型的差异及特定应用条件。引入本课题组的最新成果,梳理出合理的氯离子扩散模型。(2)针对浅层混凝土区域氯离子扩散特殊性这一问题,通过试验的方法,测定了距离混凝土表面不同距离位置处的氯离子浓度,从骨料引入和拜德-休克尔理论对扩散性的影响出发,对试验数据进行分析,建立了能普遍应用于工程实践的随深度变化的氯离子扩散模型。(3)开展考虑钢筋阻滞效应的氯离子传输规律的试验研究,测定保护层区域各处的氯离子浓度,通过将钢筋前沿与素混凝土中相应深度处的氯离子浓度进行比较分析,揭示了钢筋直接和间接这两种影响效应,最终得到了考虑钢筋阻滞效应的氯离子扩散模型。(4)采用ANSYS软件的热分析模块对氯离子浓度分布进行有限元模拟,并运用氯离子的扩散随着深度变化的研究成果,完善模型,使模拟更准确。随后对钢筋阻滞效应的各影响因素(钢筋直径、间距、混凝土保护层厚度、表面氯离子浓度)进行了全面的研究。
[Abstract]:Reinforced concrete structure is widely used in port, coastal and offshore engineering, many years of experience show that caused by the chloride ions in the marine environment, the structure of durability damage has become its design and maintenance is facing a very serious problem. Although domestic and foreign scholars have conducted a lot of research on this problem, but because of the problem is very complicated, the research is still not perfect. To study the erosion of chloride ion, the chloride diffusion model mostly ignored the effect of the presence of reinforcement and block surface reinforced concrete to the forefront of the shallow areas of concrete chloride diffusion. This paper focuses on the particularity of the first stage on the durability damage of chloride ion erosion and on the basis of previous studies, through the method of experiment and finite element analysis of reinforced block effect exists and to the front surface of the reinforced concrete The particularity of the shallow area concrete chloride ion diffusion to do some exploration. The main contents are as follows: (1) the integration of previous research results, the mechanism of large amount of chloride ion erosion contrast analysis, clear differences in the mechanism model and specific application conditions. The introduction of the latest achievements in the research group, sort out the chloride ion the reasonable diffusion model. (2) in the shallow area of concrete chloride ion diffusion problems this particularity, through experimental method, the distance of chloride ion concentration in concrete surface in different distance position was determined, and Hugh, introduced from the aggregate effects of Kerr's theory on diffusion of the analysis of test data, the establishment of the chloride ion can be generally applied to the engineering practice of the depth dependent diffusion model. (3) to carry out experimental study on the chloride ion transmission law of reinforced block effect, determination of chloride ion protective layer around the region The concentration of the chloride ion concentration, the corresponding depth of reinforced concrete in front and the comparative analysis reveals that these two kinds of direct and indirect reinforcement effect, finally obtained the chloride ion diffusion model considering the effect of reinforced block. (4) using ANSYS software the thermal analysis module of finite element simulation of chloride ion the concentration distribution, diffusion and use of chloride ion with the research results, the changes of the depth of the perfect model, make the simulation more accurate. Then the influence of reinforced block effect factors (bar diameter, spacing, thickness of concrete cover, surface chloride concentration) was studied.

【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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