干湿循环下混凝土的氯离子渗透性能及涂层防护作用研究

发布时间：2018-11-21 12:33

【摘要】：海洋混凝土结构如跨海大桥、海底隧道、穿江隧道、海洋钻井平台等常因海洋环境腐蚀而过早发生耐久性失效乃至破坏。因此，研究混凝土在长期海洋环境作用下的物理力学性能以及防腐措施显得十分重要。本文以高性能混凝土为研究对象，系统研究了干湿循环条件下氯盐侵蚀混凝土的抗渗性能和力学性能以及涂层对混凝土的防护作用，主要研究成果如下：（1）通过对氯盐侵蚀混凝土中不同深度处氯离子浓度的测定，得到了干湿循环腐蚀作用时间、防护涂层特性对混凝土氯离子渗透性能的影响规律，给出了氯离子扩散系数与干湿循环腐蚀作用时间的相互关系，由此建立了考虑时间因素的混凝土氯盐侵蚀预计模型。（2）通过单轴压缩实验，得到了氯盐侵蚀混凝土的应力-应变曲线、抗压强度、弹性模量以及峰值应变随干湿循环腐蚀作用时间的变化规律；对比分析干湿循环作用下无涂层混凝土和三种表面涂层混凝土的力学性能，给出了涂层对氯盐侵蚀混凝土抗蚀能力的影响规律。（3）基于损伤力学，研究了氯盐侵蚀对混凝土的损伤作用，得到了混凝土损伤程度随干湿循环腐蚀作用时间的变化规律，给出了氯盐侵蚀混凝土的损伤分布规律，，并构建了氯盐侵蚀混凝土单轴压缩损伤本构模型及方程。将本构方程与氯盐侵蚀混凝土单轴压缩实验结果对比，表明该本构模型可较好地描述干湿循环条件下氯盐侵蚀混凝土的损伤演化特性。研究成果可为海工混凝土耐久性的理论研究与工程应用提供参考。
[Abstract]:Marine concrete structures such as cross-sea bridges, undersea tunnels, cross-river tunnels, offshore drilling platforms, and so on often occur premature durability failure and even damage due to marine environmental corrosion. Therefore, it is very important to study the physical and mechanical properties and anticorrosion measures of concrete under the action of long-term marine environment. In this paper, the impermeability and mechanical properties of chlorine salt corroded concrete under dry and wet cycle and the protective effect of coating on concrete are systematically studied. The main research results are as follows: (1) through the determination of chloride ion concentration at different depths of chloride salt corroded concrete, the effect of wet and dry cycle corrosion time and protective coating characteristics on chloride ion permeability of concrete is obtained. The relationship between chloride diffusion coefficient and dry and wet cycle corrosion time is given, and the prediction model of chloride corrosion in concrete considering time factor is established. (2) through uniaxial compression test, the stress-strain curve, compressive strength, elastic modulus and peak strain of chloride corroded concrete are obtained. The mechanical properties of uncoated concrete and three kinds of surface coated concrete under dry and wet cycling are analyzed. The influence of coating on corrosion resistance of chloride corroded concrete is given. (3) based on the damage mechanics, the damage effect of chloride erosion on concrete is studied. The damage degree of concrete varies with the time of dry and wet cycle corrosion, and the damage distribution law of chloride salt eroding concrete is given. The constitutive model and equation of uniaxial compression damage of chloride corroded concrete are established. By comparing the constitutive equation with the experimental results of uniaxial compression of chloride corroded concrete, it is shown that the constitutive model can well describe the damage evolution characteristics of chloride corroded concrete under dry and wet cycling conditions. The results can provide a reference for the theoretical research and engineering application of marine concrete durability.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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