复杂环境硫酸盐侵蚀混凝土微观试验研究
发布时间：2018-08-19 14:46
【摘要】：混凝土硫酸盐侵蚀破坏被认为是引起混凝土结构劣化失效的四大主因之一，同时混凝土硫酸盐侵蚀也是影响因素最复杂、危害性最大的一种环境水侵蚀。我国北方某些寒冷地区的水工及海工混凝土结构，经常承受冻融循环和盐腐蚀双重因素的作用；由于潮涨潮落，使部分混凝土建筑物长期承受干湿循环，，而海水或盐渍土中又存在硫酸盐，冻融和干湿循环条件下硫酸盐侵蚀混凝土结构的破坏在工程实例中也屡见不鲜。而混凝土材料的化学组成、微观形态以及内部结构决定了其宏观力学性能，开展硫酸盐侵蚀混凝土微观结构的研究为进一步研究硫酸盐侵蚀混凝土的性能退化规律等提供依据。 本文考虑侵蚀溶液阳离子种类的影响，采用“快冻法”进行了冻融条件下硫酸盐侵蚀混凝土腐蚀试验；考虑溶液浓度、水胶比、阳离子种类等因素的影响，开展了干湿循环条件下硫酸盐侵蚀混凝土腐蚀试验。采用X射线衍射（XRD）、扫描电镜（SEM）以及TG-DSC综合热分析三种微观试验方法，对冻融及干湿循环条件下硫酸盐侵蚀混凝土腐蚀产物进行了定性及定量分析。 通过试验和分析，得出冻融条件和干湿循环条件下硫酸盐侵蚀混凝土腐蚀产物主要是钙矾石或石膏，随着龄期的增长，硫酸根离子积聚到一定浓度，才开始有石膏产物生成，且混凝土硫酸镁侵蚀与硫酸钠侵蚀相比更加严重；干湿循环下硫酸盐侵蚀混凝土水胶比越大，侵蚀溶液浓度越高越有利于腐蚀产物的生成；给出侵蚀混凝土同一深度处腐蚀产物含量变化规律以及不同侵蚀层中钙矾石和石膏含量变化。
[Abstract]:Sulfate erosion of concrete is considered to be one of the four main causes of deterioration and failure of concrete structures. At the same time, sulfate erosion of concrete is the most complex and harmful environmental water erosion. Hydraulic and marine concrete structures in some cold areas of northern China are often subjected to the double factors of freeze-thaw cycle and salt corrosion, and some concrete buildings are subjected to dry and wet cycles for a long time due to the ebb and flow of the tide. There are sulfate in seawater or saline soil, and the damage of sulphate corroded concrete structure under freeze-thaw and dry-wet cycle is also common in engineering cases. The macroscopic mechanical properties of concrete are determined by its chemical composition, microscopic morphology and internal structure. The study of the microstructure of sulphate corroded concrete provides the basis for further study on the degradation law of the performance of sulfate corroded concrete. In this paper, the influence of cations in eroding solution is considered, and the corrosion test of sulphate corroded concrete under freeze-thaw condition is carried out by "quick freezing method", and the effects of concentration of solution, ratio of water to binder, kinds of cations and so on are taken into account. The corrosion test of sulphate corroded concrete under dry and wet cycle was carried out. The corrosion products of sulphate corroded concrete under freeze-thaw and dry-wet cycling conditions were qualitatively and quantitatively analyzed by X-ray diffraction (XRD),) scanning electron microscope (SEM) and comprehensive thermal analysis (TG-DSC). Through test and analysis, it is concluded that the corrosion products of sulphate corroded concrete under freeze-thaw conditions and dry and wet cycle conditions are mainly ettringite or gypsum. With the increase of age, sulphate ion accumulates to a certain concentration before gypsum products are formed. The higher the ratio of water to binder is, the higher the concentration of corrosion solution is, and the higher the concentration of corrosion solution is, the better the formation of corrosion products is, and the higher the ratio of water to binder is, the more serious the erosion of concrete is compared with the erosion of sodium sulfate. The changes of ettringite and gypsum contents in different erosive layers are given.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528.0
本文编号：2191972
[Abstract]:Sulfate erosion of concrete is considered to be one of the four main causes of deterioration and failure of concrete structures. At the same time, sulfate erosion of concrete is the most complex and harmful environmental water erosion. Hydraulic and marine concrete structures in some cold areas of northern China are often subjected to the double factors of freeze-thaw cycle and salt corrosion, and some concrete buildings are subjected to dry and wet cycles for a long time due to the ebb and flow of the tide. There are sulfate in seawater or saline soil, and the damage of sulphate corroded concrete structure under freeze-thaw and dry-wet cycle is also common in engineering cases. The macroscopic mechanical properties of concrete are determined by its chemical composition, microscopic morphology and internal structure. The study of the microstructure of sulphate corroded concrete provides the basis for further study on the degradation law of the performance of sulfate corroded concrete. In this paper, the influence of cations in eroding solution is considered, and the corrosion test of sulphate corroded concrete under freeze-thaw condition is carried out by "quick freezing method", and the effects of concentration of solution, ratio of water to binder, kinds of cations and so on are taken into account. The corrosion test of sulphate corroded concrete under dry and wet cycle was carried out. The corrosion products of sulphate corroded concrete under freeze-thaw and dry-wet cycling conditions were qualitatively and quantitatively analyzed by X-ray diffraction (XRD),) scanning electron microscope (SEM) and comprehensive thermal analysis (TG-DSC). Through test and analysis, it is concluded that the corrosion products of sulphate corroded concrete under freeze-thaw conditions and dry and wet cycle conditions are mainly ettringite or gypsum. With the increase of age, sulphate ion accumulates to a certain concentration before gypsum products are formed. The higher the ratio of water to binder is, the higher the concentration of corrosion solution is, and the higher the concentration of corrosion solution is, the better the formation of corrosion products is, and the higher the ratio of water to binder is, the more serious the erosion of concrete is compared with the erosion of sodium sulfate. The changes of ettringite and gypsum contents in different erosive layers are given.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528.0
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本文编号：2191972
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