中文摘要：

混凝土结构通常受土壤环境水中硫酸盐和镁盐溶液的侵蚀。为了探究硫酸盐和镁盐复合溶液侵蚀后纯水泥混凝土和掺矿粉微粉高性能混凝土的抗侵蚀性能，该研究设计了3个水胶比和2个矿粉掺量，经加水拌合、成型试件1050个，养护28 d后将其分别浸泡于硫酸盐和镁盐溶液中，侵蚀至规定龄期后测试其抗蚀系数、微观形貌。结果表明：水胶比为0.50时，混凝土界面中的孔隙多、孔径大，最大孔径为372.5μm，即使水胶比降低到0.35时，其孔结构的改善也不明显。当纯水泥混凝土试件在SO42-2500 mg/L和Mg2＋1400 mg/L的硫酸盐镁盐中侵蚀4个月后，其孔隙中充满了CaSO4·2H2O、3CaO·Al2O3·3CaSO4·32H2O（AFt）、Mg（OH）2和MgO·SiO2·H2O等侵蚀产物，致使混凝土内部产生裂缝，边角处开始出现剥落，甚至变得酥松，表面浆体脱落严重，粗细集料分离等现象。当侵蚀时间超过2月时，其侵蚀系数随侵蚀龄期的延长呈降低的趋势，且均在0.85以下，说明32.5级普通硅酸盐水泥抗硫酸盐镁盐侵蚀的能力是有限的。矿渣微粉掺入后，混凝土界面的孔隙不仅极少，而且孔径也较小，最大孔径分别约为水胶比为0.50时的1/7和1/8，同时也减少了易被侵蚀的水化产物 Ca（OH）2的含量，使混凝土界面结构密实程度增加，水胶比越低越明显。在高浓度的硫酸盐和镁盐（SO42-20250 mg/L和Mg2＋2800 mg/L）的双重强侵蚀12个月后，试件边缘仍未发现侵蚀产物以及MgSO4·7H2O、Na2SO4·10H2O和Mg2（OH）3Cl·4H2O等晶体，其抗蚀系数仍在0.85以上，未有降低的趋势，表明矿渣微粉的掺入能显著改善32.5级普通硅酸盐水泥所配制高性能混凝土的抗侵蚀性能。该研究可为混凝土在农业灌溉工程（坝基础、闸基础和渠道等）和大棚混凝土基础工程的使用提供数据支撑与理论基础。

英文摘要：

Concrete structure is usually affected by sulfate and magnesium salt in soil water environmental. In order to explore anti-erosion properties of cement concrete and high-performance concrete mixed with slag powder after immersed in solution with sulfate and magnesium salt, the study designed three water-binder ratio treatments and two slag powder content treatments. After mixing with water, 1050 specimens （10 mm×10 mm×60 mm） were prepared and incubated in conditions of 20℃ and moisture≥9.5% for 28 d. Then, they were immersed in five different solutions with different sulfate and magnesium concentrations for determine anti-erosion coefficient and microstructure of the specimens during erosion. The results showed that： The cement had many pores with large pore size when water-binder ratio was 0.50, and the maximum diameter of pore reached 372.5μm. The improvement of the pore structure was not obvious when the water-binder ratio decreased to 0.35. When the pure cement concrete specimens was immersed in solution with 2500 mg/L SO42- and 1400 mg/L magnesium2＋ for 4 months. The pores of specimens were full of hydration products such as CaSO4·2H2O, 3CaO·Al2O3·3CaSO4·32H2O （AFt）, and a small amount of Mg（OH）2 and MgO-SiO2？H2O, which could lead to cracks in concrete, peeling off the side parts, even being crisp and surface slurry loss seriously. After 2 months, the erosion coefficient showed a downward trend with erosion duration and was below 0.85, indicating a limited anti-erosion capacity of silicon concrete. When the concrete was added with slag powder, the pore numbers became small and pore size was small. The largest pore size of concrete with water-binder ratio of 0.35 and 0.30 was only 1/7 and 1/8 times as that of concrete with water-binder ratio of 0.50. Meanwhile, the content of Ca（OH）2 was reduced. The concrete structure became loose, which was more obvious for specimens with low water-binder ratio. After 12 months of erosion in solution of sulfate and magnesium salt （20250mg/