氯盐—硫酸盐侵蚀下混凝土的损伤劣化机理研究

发布时间：2018-09-19 10:02

【摘要】：随着沿海基础设施与港口群的建设以及海洋工程特色产业的发展,提高混凝土在海洋环境中的耐久性对改善工程质量及使用寿命有着十分重要的现实意义。氯盐-硫酸盐侵蚀下混凝土的损伤劣化机理研究是解决混凝土在海洋环境中耐久性问题的基础。本文以C45普通硅酸盐水泥混凝土为研究对象,综合应用试验研究、理论分析等研究方法,系统地研究了在氯盐-硫酸盐溶液侵蚀作用下,氯离子和硫酸根离子的扩散规律及混凝土的力学性能和损伤劣化规律,取得如下研究成果:(1)测定了距试样表面不同深度处的氯离子含量和硫酸根离子含量,研究了侵入混凝土内部的氯离子和硫酸根离子含量随侵蚀溶液中离子浓度的变化规律及其在扩散过程中的相互影响。基于Fick第二定律计算了氯离子和硫酸根离子的扩散系数,分别给出了氯离子和硫酸根离子的扩散影响方程。(2)测试得到了不同侵蚀溶液浓度条件下混凝土的应力-应变曲线,研究了混凝土材料的抗压强度、弹性模量、峰值应变随侵蚀溶液中氯离子和硫酸根离子浓度的变化规律,揭示了氯盐-硫酸盐侵蚀作用下混凝土力学性能的劣化特征。(3)基于混凝土损伤力学理论,以弹性模量和割线模量为对象定义损伤变量,依据不同浓度组合条件下混凝土的力学试验结果,得到了混凝土材料的氯盐-硫酸盐溶液侵蚀损伤演化规律、弹塑性损伤演化规律,建立了混凝土的损伤本构方程;根据应力-应变试验曲线确定了方程的具体参数。理论与试验结果较为吻合。
[Abstract]:With the construction of coastal infrastructure and port group and the development of marine engineering industry, it is very important to improve the durability of concrete in marine environment to improve engineering quality and service life. The study of damage deterioration mechanism of concrete under chloride sulfate erosion is the basis to solve the durability problem of concrete in marine environment. In this paper, the C45 ordinary Portland cement concrete is taken as the research object, the comprehensive applied experimental study, theoretical analysis and other research methods, under the chlorine salt-sulfate solution erosion, The diffusion law of chloride ion and sulfate ion and the mechanical properties and damage deterioration of concrete have obtained the following results: (1) the chloride ion content and sulfate ion content at different depth from the surface of the sample were measured. The variation of chloride ion and sulfate ion content in invading concrete with ion concentration in erosive solution and their interaction in diffusion process were studied. Based on the second law of Fick, the diffusion coefficients of chloride ion and sulfate ion are calculated, and the diffusion equations of chloride ion and sulfate ion are given respectively. (2) the stress-strain curves of concrete under different concentration of corrosive solution are obtained. The variation of compressive strength, elastic modulus and peak strain of concrete with the concentration of chloride ion and sulfate ion in erosive solution was studied. The deterioration characteristics of mechanical properties of concrete under chloride sulfate erosion are revealed. (3) based on the theory of damage mechanics of concrete, the elastic modulus and Secant modulus are taken as the object to define the damage variables. According to the mechanical test results of concrete under different concentration combinations, the damage evolution law of chloride sulfate solution and elastoplastic damage evolution law of concrete material are obtained, and the damage constitutive equation of concrete is established. The specific parameters of the equation are determined according to the stress-strain test curve. The theoretical results are in good agreement with the experimental results.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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