水泥基材料物相组成对其抗硫酸盐侵蚀性能的影响机理

硫酸盐侵蚀过程中硫酸根离子会与水泥的水化产物发生化学反应，从而导致基体的膨胀破坏。因此，水泥基材料的物相与化学组成对于抗硫酸盐侵蚀性能存在较大的影响。但是随着矿物掺合料的大量使用，水泥基材料水化产物的物相组成愈加复杂，现有研究尚未阐明水泥基材料的物相组成与其在硫酸盐侵蚀过程中微观结构与宏观性能变化之间的关系。.本课题采用化学分析和微观测试手段定量分析水泥及矿物掺合料在水化前后的物相组成与元素分布，并根据反应基本原理和质量守恒方法找到两者之间的对应关系；基于耐久性试验方法和微观分析手段，研究水泥基材料在硫酸盐侵蚀过程中物相组成、微观结构与宏观性能的变化规律。通过实验研究，阐明硫酸盐与水化产物反应生成侵蚀产物的机理，并揭示侵蚀产物对于水泥基材料微观结构和宏观性能的影响规律，最终得到水泥基材料物相组成对其在硫酸盐侵蚀作用下服役性能的影响规律与作用机理，为提高混凝土的耐久性提供试验和理论依据。

For cementitious materials under sulfate attack, sulfate ions from environmental will react with hydration product, leading to the expansion and thus failure of materials. Therefore, the chemical constitution and phase composition of cementitious materials have a significant impact on the sulfate attack resistance. However, the phase composition now is even more complicated with the extensive use of supplementary cementitious materials (SCMs). Consequently, there is no clear relationship between the phase composition, microstructure and macroscopic properties of cementitious materials under sulfate attack..In the present project, firstly, the phase composition and element distribution of cementitious materials before and after hydration will be investigated by chemical analysis and microstructure analysis. Then, based on durability test method, the variation of phase composition, microstructure and macroscopic properties of cementitious materials under sulfate attack will be monitored, in order to clarify the effect of erosion products on the microstructure change of cementitious materials, and then the degradation of macroscopic properties. Finally, the affecting mechanism of chemical phase composition on the sulfate resistance of cementitious materials will be proposed. The achievement of this project will provide important experimental and theoretical experience for improving the durability of concrete structures in severe conditions (river, underground water, soils) containing large amounts of sulfates..