荷载作用下混凝土碳化与氯盐侵蚀相互影响试验研究

发布时间：2018-01-07 03:26

本文关键词：荷载作用下混凝土碳化与氯盐侵蚀相互影响试验研究　出处：《浙江大学》2013年硕士论文　论文类型：学位论文

【摘要】：碳化与氯盐侵蚀是导致钢筋混凝土结构服役性能劣化的重要原因,荷载作用及碳化作用对氯离子的侵蚀有显著影响。研究碳化对混凝土的影响,以及荷载、碳化和氯盐侵蚀三者之间影响关系,对准确预测钢筋混凝土结构的服役寿命具有十分重要的意义。该论文以此为主线,重点研究了碳化对混凝土的影响,荷载对混凝土碳化的影响,碳化对氯盐的影响以及荷载对氯盐侵蚀的影响等相互作用机理与相关试验。主要研究工作如下： (1)设计了一种混凝土碳化深度的较精确的测量方法,提出了碳化后CaCO3随深度变化的关系。同时,通过试验揭示碳化对混凝土的微观结构影响,对研究混凝土碳化提供了一定经验和试验成果。 (2)通过试验得到拉应变和碳化的变化关系,将不同应变下的碳化试验结果与同条件下无应力状态下的碳化进行定量比较并拟合得到函数关系,得到混凝土随拉应变变化的时变碳化深度计算简式。基于开裂混凝土碳化试验,提出碳化过程中裂缝产生自愈合现象,并提出混凝土碳化自愈合时变理论框架。利用环境扫描电子显微镜(ESEM)和能谱分析仪(EDS)观察并分析裂缝自愈合程度,通过试验监测裂缝中CaCO3的形成过程并基于碳化反应原理建立裂缝随着碳化过程变化的数值解。基于Fick定律和扩散传递原理,建立了碳化作用下沿着裂缝深度方向开裂混凝土扩散系数。基于ANSYS有限元软件和试验验证,分析了裂缝宽度对垂直于裂缝深度方向的碳化程度的影响及模型的适应性。 (3)通过分析碳化对水分和氯离子的传输影响,基于碳化对混凝土毛细吸水实验、氯离子结合能力影响试验等建立碳化对混凝土氯离子传输影响理论模型。 (4)考虑不同浇筑面朝向、箍筋位置、摆放位置对氯离子分布及钢筋锈蚀的影响,对盐雾环境与荷载耦合作用下锈蚀钢筋混凝土中氯离子分布情况及锈蚀发展状态进行了探讨,旨在为海洋大气区钢筋混凝土结构的耐久性设计起到铺垫作用。
[Abstract]:Carbonation and chloride erosion are the important reasons leading to the deterioration of service performance of reinforced concrete structures. Load and carbonation have a significant impact on chloride erosion. The effect of carbonation on concrete and load are studied. The relationship between carbonation and chloride erosion is very important to predict the service life of reinforced concrete structure accurately. This paper focuses on the influence of carbonation on concrete. The influence of loading on concrete carbonation, the influence of carbonation on chloride and the effect of load on chloride erosion, and so on, and related experiments. The main research work is as follows: 1) A more accurate measuring method of carbonation depth of concrete is designed, and the relation of CaCO3 with depth after carbonization is put forward. At the same time, the influence of carbonization on microstructure of concrete is revealed by experiments. Some experience and experimental results are provided for the study of concrete carbonization. (2) the relationship between tensile strain and carbonation is obtained by experiment, and the results of carbonation test under different strain are compared quantitatively with carbonization under the same condition without stress and the functional relationship is obtained. A simple formula for calculating the time-varying carbonation depth of concrete with tensile strain is obtained. Based on the carbonation test of cracked concrete, the phenomenon of self-healing of cracks in the carbonization process is proposed. The time-varying theoretical framework of concrete carbonization self-healing is proposed. The self-healing degree of cracks is observed and analyzed by using ESEM and EDS. The formation process of CaCO3 in fracture was monitored by experiments and the numerical solution of crack changing with carbonation process was established based on carbonation reaction principle, based on Fick law and diffusion transfer principle. The diffusion coefficient of cracked concrete along the crack depth under carbonation is established, based on ANSYS finite element software and experimental verification. The influence of fracture width on carbonation degree perpendicular to fracture depth and the adaptability of the model are analyzed. By analyzing the effect of carbonation on the transport of water and chloride ions, the capillary water absorption experiments of concrete based on carbonation are carried out. A theoretical model of the effect of carbonation on chloride ion transport in concrete was established. (4) considering the influence of different pouring face orientation, stirrups position and placement position on chloride ion distribution and reinforcement corrosion. The distribution and corrosion development of chloride ions in corroded reinforced concrete under the coupled action of salt fog environment and load are discussed in order to pave the way for durability design of reinforced concrete structures in marine large gas area.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU375

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