基于不同胶凝材料钢筋混凝土耐蚀性试验研究

发布时间：2018-05-23 19:25

本文选题：钢筋混凝土 + 耐久性　；参考：《兰州理工大学》2017年硕士论文

【摘要】：目前,钢筋混凝土结构在硫酸盐和氯盐的共同作用下耐腐蚀性研究较多,而在镁盐、硫酸盐和氯盐多因素耦合作用下的耐腐蚀性研究相对较少。同属西部地区,甘肃省酒泉地区是重盐渍土地区,青海省格尔木地区含有大量的盐湖。在西部重盐渍土和盐湖地区普通硅酸盐水泥钢筋混凝土的腐蚀非常严重,盐卤侵蚀对钢筋混凝土的耐久性和安全性产生了严重的威胁。镁水泥具有不加改性的抗盐卤腐蚀的性能,同时西部盐湖又有大量的镁水泥原材料,所以研究它对西部盐湖的开发有着重要的意义。由于镁水泥本身对钢筋有较强的腐蚀作用,本文采用涂层对钢筋进行保护,研究镁水泥钢筋混凝土在西部地区抗盐卤腐蚀有着理论意义和社会经济价值。本文设计了6组钢筋混凝土试块,分别为Mg-GHT(镁水泥混凝土-环氧树脂涂层钢筋)、Mg-B(镁水泥混凝土-裸露钢筋)、P.O.1-GHT(配比1硅酸盐水泥混凝土-环氧树脂涂层钢筋)、P.O.1-B(配比1硅酸盐水泥混凝土-裸露钢筋)、P.O.2-GHT(配比2硅酸盐水泥混凝土-环氧树脂涂层钢筋)、P.O.2-B(配比2硅酸盐水泥混凝土-裸露钢筋)。采用电化学方法、电阻法、室内快速腐蚀试验和现场暴露试验的方法对钢筋混凝土基于不同胶凝材料的耐蚀性试验研究。研究内容和成果有:1.定期对长期浸泡于耦合溶液中的试块进行电化学检测,通过极化曲线和交流阻抗分析研究了混凝土中钢筋抗氯盐、硫酸盐和镁盐的腐蚀规律,得出在耦合盐溶液中Mg-GHT抗腐蚀能力优于P.O-B。2.模拟了酒泉和格尔木地区的实际环境,考虑了冻融循环、紫外线照射等因素,设计了室内大循环快速腐蚀试验和现场暴露试验。定期检测了混凝土波速、质量和钢筋电阻,以混凝土的相对动弹性模量评价参数ω1、钢筋混凝土的相对质量评价参数ω2、作为基本耐久性评价指标。为了能够可观的反应钢筋混凝土的腐蚀程度设计了钢筋的平均截面未锈蚀评价参数ω3及钢筋混凝土的损伤程度评价参数ω为评价指标。分析了钢筋混凝土抗氯盐、硫酸盐和镁盐的腐蚀规律,得出在盐卤侵蚀的环境下镁水泥涂层钢筋混凝土抗腐蚀能力优于硅酸盐水泥裸露钢筋混凝土。3.结合EDS能谱分析和SEM电镜扫描,分析了钢筋混凝土腐蚀后的产物,确定生成物的微观结构相貌及组成成分,并进一步分析了钢筋混凝土腐蚀机理及规律。通过以上研究得出在盐湖和重盐渍土环境下镁水泥涂层钢筋混凝土比硅酸盐水泥裸露钢筋混凝土更具有优越性。由于镁水泥混凝土自身比较密实,其制约了外部环境中腐蚀性离子的渗入,所以在镁水泥原材料丰富的地区可以考虑使用镁水泥涂层钢筋混凝土。
[Abstract]:At present, the corrosion resistance of reinforced concrete structures under the combined action of sulfate and chloride is much studied, but the corrosion resistance of reinforced concrete structures under the coupling of magnesium salt, sulfate and chlorine salt is relatively few. The Jiuquan area of Gansu Province is a heavy saline land area, and the Golmud area of Qinghai Province contains a large number of salt lakes. The corrosion of common Portland cement reinforced concrete in the western heavy saline soil and salt lake area is very serious, and the salt and halogen corrosion is a serious threat to the durability and safety of reinforced concrete. Magnesium cement has the property of resisting salt and halogen corrosion without modification, and at the same time, there are a lot of magnesium cement raw materials in western salt lake, so it is of great significance to study it for the development of western salt lake. Since magnesium cement has a strong corrosion effect on steel bars, it is of theoretical significance and social and economic value to study the resistance of magnesium cement reinforced concrete to salt and halogen corrosion in the western region. In this paper, six groups of reinforced concrete test blocks are designed. Mg-GHTMg-B (magnesium cement concrete / epoxy resin coated steel bar) P.O.1-GHT (ratio 1 Portland cement concrete-epoxy resin coated steel bar) P.O.1-B (ratio 1 Portland cement concrete-exposed steel bar) Ratio 2 Portland cement concrete-epoxy resin coated steel bar P.O.2-B (ratio 2 Portland cement concrete-bare steel bar). The corrosion resistance of reinforced concrete based on different cementing materials was studied by electrochemical method, resistance method, indoor rapid corrosion test and field exposure test. The contents and results of the study are as follows: 1. The corrosion resistance of steel bars to chloride, sulfate and magnesium in concrete was studied by polarization curve and AC impedance analysis. The results show that the corrosion resistance of Mg-GHT in coupling salt solution is better than that of P.O-B.2. The actual environment in Jiuquan and Golmud area was simulated and the factors such as freeze-thaw cycle ultraviolet radiation and so on were considered. The indoor rapid corrosion test and field exposure test were designed. The wave velocity, mass and steel resistance of concrete are measured periodically. The relative dynamic modulus of concrete (蠅 1) and the relative quality of reinforced concrete (蠅 2) are taken as the basic durability evaluation index. In order to reflect the corrosion degree of reinforced concrete, the evaluation parameters 蠅 3 of average section and 蠅 3 of damage degree of reinforced concrete are designed. The corrosion resistance of reinforced concrete to chloride, sulfate and magnesium salt is analyzed. It is concluded that the corrosion resistance of reinforced concrete coated with magnesium cement is better than that of exposed reinforced concrete with Portland cement under the environment of salt and halogen erosion. Combined with EDS energy spectrum analysis and SEM scanning electron microscope, the corrosion products of reinforced concrete were analyzed, the microstructure and composition of the product were determined, and the corrosion mechanism and law of reinforced concrete were further analyzed. It is concluded that magnesium cement coated reinforced concrete is superior to Portland cement exposed reinforced concrete in salt lake and heavy saline soil. Because the magnesium cement concrete itself is relatively dense, it restricts the infiltration of corrosive ions in the external environment, so the use of magnesium cement coated reinforced concrete can be considered in the areas rich in magnesium cement raw materials.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528.571

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