海洋浪溅区混凝土内部湿度传输规律及其抗氯离子侵蚀性能

发布时间：2019-06-10 21:04

【摘要】：干湿循环条件是对海工结构耐久性最不利的环境之一,干湿循环条件下混凝土内部湿度和离子传输的机理比单调干燥或者湿润条件下更复杂。研究干湿循环条件下混凝土内部湿度传输规律及其抗氯离子侵蚀性能,对开展海工结构耐久性研究、提高海工结构服役安全性具有重要意义。本文针对以上问题,通过试验研究、有限元模拟,研究海洋浪溅区干湿循环循环条件下混凝土内部的湿度传输规律及其抗氯离子侵蚀性能,主要内容如下:(1)研究了混凝土内部湿度变化规律,设计了室内条件下混凝土内部温湿度长期变化规律试验,以及干湿循环条件下混凝土内部湿度变化规律试验。试验结果表明室内条件下混凝土内部湿度变化受水化耗水、环境湿度、矿物掺合料以及水胶比影响,干湿循环条件下混凝土内部湿度变化主要受干湿循环周期、距离表面深度以及水胶比等因素的影响。(2)建立室内环境下和干湿循环条件下混凝土内部湿度传输模型,考虑室内环境和干湿循环条件下两种模型的不同边界条件,以室内环境的数值计算结果作为干湿循环模型的初始值。利用Comsol multiphysics有限元模拟软件求解模型。结果表明,湿度传输模型数值计算结果与实测结果变化规律较为一致,说明本文建立的湿度传输模型可用于分析预测混凝土中的湿度传输规律。(3)进行干湿循环、全浸泡侵蚀条件下氯离子的侵蚀试验,研究不同侵蚀条件下氯离子的入侵深度和不同深度处氯离子的浓度。建立氯离子传输模型,并利用COMSOL有限元软件实现氯离子传输模型的分析求解,研究干湿循环、全浸泡条件下氯离子传输过程。结果表明模型数值计算值与试验实测值的吻合情况较好。(4)研究干湿循环-氯盐复合侵蚀条件下水泥基复合材料微结构变化,设计不同层次水泥基复合材料试件,采用XRD、DTA、FTIR等多种微观测试技术,定性分析了干湿循环-氯离子侵蚀条件水泥基复合材料内部微观结构结构特征。结果表明,氯盐侵蚀下明显生成了Friedel盐,而掺入矿粉掺合料能增强水泥基复合材料的氯离子结合能力。
[Abstract]:The dry and wet cycle condition is one of the most unfavorable environments for the durability of the marine structure, and the mechanism of the internal humidity and the ion transport in the concrete is more complex than the monotone drying or wetting condition. It is of great significance to carry out the research on the durability of the marine structure and to improve the service safety of the marine structure. In the light of the above problems, by means of the experimental research and the finite element simulation, the moisture transfer law and the anti-chloride corrosion performance of the concrete inside the concrete are studied. The main contents are as follows: (1) The change rule of the internal humidity of the concrete is studied. In this paper, the long-term change of the temperature and humidity of the concrete under the condition of room temperature is designed, and the variation law of the internal humidity of the concrete under the condition of dry and wet circulation is tested. The results show that the change of the internal humidity of the concrete under the indoor conditions is affected by the water consumption, the environmental humidity, the mineral admixture and the water-cement ratio, and the change of the internal humidity of the concrete under the dry and wet cycle is mainly affected by the dry and wet cycle, the depth of the distance surface and the water-to-gel ratio. (2) The internal humidity transfer model of the concrete under the condition of indoor environment and dry and wet circulation is established, and the numerical results of the indoor environment are taken as the initial value of the dry and wet circulation model, taking into account the different boundary conditions of the two models under the indoor environment and the dry and wet cycle conditions. The model is solved by using the Cosol multiphysics finite element simulation software. The results show that the numerical results of the humidity transfer model are consistent with the measured results, and the humidity transfer model established in this paper can be used to analyze and predict the humidity transfer rule in the concrete. (3) The corrosion test of chloride ion under the condition of dry and wet circulation and full immersion erosion is carried out, and the concentration of chloride ion at different depth and depth under different erosion conditions is studied. The chloride ion transport model was established and the chloride ion transport model was solved by using the COMSOL finite element software. The process of chloride ion transmission under the condition of dry and wet and full immersion was studied. The results show that the calculated value of the model is good with the experimental data. (4) The microstructure of the cement-based composite was studied under the condition of dry-wet and cyclic-chlorine-salt composite erosion, and a variety of micro-test techniques such as XRD, DTA and FTIR were used to design the test piece of cement-based composite material at different levels. The microstructure characteristics of the internal microstructure of the cement-based composite based on the wet and wet cycle-chloride ion erosion condition are analyzed qualitatively. The results show that the Friedel salt is obviously produced under the erosion of the chloride, and the incorporation of the mineral powder admixture can enhance the chloride ion binding ability of the cement-based composite.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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