氯盐环境中纳米偏高岭土在水泥砂浆中合理掺量研究

摘要

In order to study the reasonable addition of nano metakaolin in cement mortar in the chloride environment,the effect of seven kinds of nano metakaolin additive(0,1%,2%,3%,4%,5%,6%)on the fluidity,mechanical properties and chloride permeability of cement mortar were examined.The relationship between the chloride diffusion coefficient and the curing age of cement mortar with different nano metakaolin addition was analyzed.The fluidity,flexural strength,compressive strength and chloride permeability of cement mortar as the evaluation index was studied by analytic hierarchy process,to explore the reasonable addition of nano metakaolin in cement mortar with good durability.The results show that the incorporation of nano metakaolin decreases the fluidity of cement mortar while increases the flexural strength,compressive strength and resistance to chloride permeability.The relationship between chloride diffusion coefficient and curing time of cement mortar is exponential relationship,and the chloride diffusion coefficient with 4% nano metakaolin additive had the largest age coefficient.The durability of the cement mortar with 3% nano metakaolin additive in the chloride environment was the best.%为获得氯盐环境中纳米偏高岭土在水泥砂浆中的合理掺量,开展了7种掺量纳米偏高岭土(0、1%、2%、3%、4%、5%、6%)对水泥砂浆流动性、力学性能与氯离子渗透性能影响的试验研究;分析了不同纳米偏高岭土掺量下水泥砂浆氯离子扩散系数与龄期的关系;以流动性、抗折强度、抗压强度与氯离子渗透性为评价指标,采用层次分析法探讨了纳米偏高岭土对改善水泥砂浆耐久性的合理掺量.研究表明,掺纳米偏高岭土导致水泥砂浆流动度降低,抗折强度、抗压强度和抗氯离子渗透性提高;水泥砂浆试件氯离子扩散系数随时间增长呈指数衰减规律,掺4%纳米偏高岭土时水泥砂浆氯离子扩散系数的龄期系数最大;掺3%纳米偏高岭土时水泥砂浆在氯盐环境中的耐久性最好.