水泥基材料在腐蚀环境中生成碳硫硅钙石的机理研究

发布时间：2018-04-25 03:02

本文选题：硫酸镁 + 碳酸钠　；参考：《建筑材料学报》2017年06期

【摘要】：为探索石灰石粉混凝土在低温硫酸盐环境下生成碳硫硅钙石的机理,将石灰石粉混凝土及采用硫铝酸盐水泥制备的水泥基胶凝材料分别浸泡于质量分数为10%的硫酸镁溶液和碳酸钠溶液中,进行抗压强度测试,并通过扫描电镜(SEM)、X射线衍射(XRD)及红外光谱等微观试验手段,研究并分析了碳硫硅钙石的形成原因.结果表明:低温硫酸镁溶液中的石灰石粉混凝土抗压强度随浸泡时间的延长呈现先增长后减小的趋势,表面出现膨胀剥落现象,生成大量的二水石膏,发生膨胀腐蚀;碳酸钠溶液中的硫铝酸盐水泥基胶凝材料发生了泥化现象,其抗压强度随浸泡时间延长逐渐降低,内部水化产物钙矾石随浸泡时间延长逐渐减少,发生异相结晶转换生成碳硫硅钙石.混凝土中掺加石灰石粉并不是造成碳硫硅钙石型硫酸盐腐蚀(TSA)的主要因素,水泥基胶凝材料硬化体中的钙矾石长期处于含CO2-3环境中才会生成大量烂泥状的碳硫硅钙石,造成胶凝材料破坏.
[Abstract]:In order to explore the formation mechanism of limestone powder concrete in low temperature sulphate environment, Limestone concrete and cement based cementitious material made of sulphoaluminate cement were immersed in 10% magnesium sulfate solution and sodium carbonate solution, respectively, and the compressive strength was tested. The causes of formation of carbonite were studied and analyzed by means of scanning electron microscope (SEM) and X-ray diffraction (XRD) and infrared spectroscopy. The results show that the compressive strength of limestone concrete in low temperature magnesium sulfate solution increases first and then decreases with the prolongation of soaking time. The phenomenon of expansion and exfoliation occurs on the surface and a large number of gypsum dihydrate is formed and expanded and corroded. The sulphoaluminate cement based cementitious material in sodium carbonate solution is mudded, its compressive strength decreases gradually with the time of soaking, and the internal hydration product ettringite decreases with the prolongation of soaking time. The heterogeneous crystallization conversion was carried out to form calcite. The addition of limestone powder in concrete is not the main factor causing the corrosion of carbonite-type sulphate in concrete. Ettringite in cement based cementing material sclerosing body can only produce a large amount of muddy calcium carbonate in CO2-3 environment for a long time. Causing damage to the cementing material.
【作者单位】：北京科技大学金属矿山高效开采与安全教育部重点实验室;北京科技大学土木与资源工程学院;北京节能减排关键技术协同创新中心;河南工业大学土木建筑学院;
【基金】：国家自然科学基金资助项目(51374036,51578039)
【分类号】：TU528

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