【作者】 李固华；

【导师】 高波；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2006， 博士

【摘要】 混凝土是当今土木工程中用途最广泛建筑材料之一。在恶劣的环境下，混凝土长期遭受腐蚀介质的作用，导致混凝土结构性能的裂化、耐久性降低而提前发生破坏。对于土木工程来讲，改善混凝土的耐久性已经成为研究的热点。 由于纳米材料具有的特殊性能而被誉为21世纪的新材料。但是其成本较高，用于改善混凝土性能的研究还较少。随着纳米材料制造成本的降低，其应用领域也将越来越广泛，也为纳米材料在高耐久性混凝土和高性能混凝土中的应用带来了希望。 本文采用X衍射分析（XRD）、扫描电镜（SEM）、透射电镜（TEM）和扫描电子显微镜X射线能谱分析（EDXA）研究了纳米SiO₂和纳米CaCO₃在水泥中的水化过程。分析了掺入纳米SiO₂和纳米CaCO₃的混凝土微观结构特点，研究了掺纳米CaCO₃水泥浆的化学组成，提出纳米CaCO₃延缓钙矾石AFt向AFm转化的理论。 采用抗压强度、氯离子渗透、硫酸盐腐蚀、腐蚀干湿循环等试验研究了掺纳米材料与硅灰、粉煤灰等复合的混凝土性能。分析探讨了纳米材料对混凝土性能的影响规律和影响机理。试验内容丰富而且试验周期长，耐硫酸盐腐蚀试验6个月，干湿腐蚀循环次数达到110次（110d），氯离子渗透试验龄期达到180d，为纳米材料在混凝土中应用，提供试验资料和理论依据。 提出用纳米材料配制耐腐蚀铺料来提高混凝土耐久性的方法。结合各种混凝土掺和料、纳米材料在混凝土耐久性能中的表现，并参考国内外有关的试验研究资料，确定耐腐蚀混凝土的辅料主要成分和配比。通过混凝土离子渗透性试验、硫酸盐腐蚀试验、干湿腐蚀循环试验等对耐腐蚀辅料的性能进行了测试。更多还原

【Abstract】 Concrete is one of the building materials widely used in civil engineering. When concrete strutures are exposed in severe environment, its performance becomes inferior, which decreases its durability and leads it to damage in advance. It has become a hot topic to study for the civil engineering to improve durability of concrete.Having special performances, nano-material was called new material in 21 st Century. Study on which nano-material was used to improve concrete performance was very little. Nano-materials will apply to more wide field with study of nano-materials and decrease of their cost and it bring hope for nano-materials to be used in high durability concrete and high performance concrete.Hydration of nano-SiO₂ and nano-CaCO₃ in cement paste were studied by XRD, SEM, TEM and EDXA. Microstruction of the concrete with nano-SiO₂ or nano-CaCO₃ were analyzed. Compositions of the cement paste with nano- CaCO₃ was investigated and it was presented that nano-CaCO₃ can baffle ettringite （AFt） transforming to Afm.The performances of concrete with nano-materials, Silica Fume and fly ash were investigated in the experiments such as compress strength, concrete chloride diffusivity, sulfate resistance and drying/wetting cycle in corrosive environments etc. Action rules and mechanisms of nano-materials on the concrete were analyzed and discussed. Content of the experiments was great and their terms were long enough such as 6 months sulfate resistance, 110 times （110d） drying/wetting cycle in corrosive environments and 180d chloride diffusivity. Experiment datum and hypotheses were supplied for using of nano-materials in concrete.A means which an anticorrosive mixture with nano-materials is used to improve durability of the concrete was given. Main Compositions and mix proportions were chosen based on behaviors of nano-materials and mineral admixtures （blending materials） in durability of the concrete as well as other domestic and international relational datum. The performances of concrete with the anticorrosive mixture were investigated in the experiments such as concrete chloride diffusivity, sulfate resistance and drying/wetting cycle in corrosive environments etc. It is very effective for concrete to improve concrete durability更多还原