【摘要】 通过宏观性能测试、化学分析和微观分析,本文研究了磷酸钾镁水泥（MKPC）浆体试件浸泡在质量分数为5%Na₂SO₄溶液中的硫酸根离子扩散及强度发展规律。结果表明,随着浸泡龄期的延长,试件内部硫酸根离子的含量逐步提高,侵蚀深度逐渐增加。硫酸根离子的侵蚀深度与硫酸根离子含量之间的关系基本满足2阶或3阶多项式（相关系数R2大于0.998）,采用Fick第二扩散定律解析式求解得到MKPC试件的硫酸根离子扩散系数均为10^-7mm²/s数量级,比硅酸盐水泥混凝土小一个数量级。浸泡龄期不超过180 d时,MKPC试件的硫酸根离子扩散系数呈下降趋势;超过180 d后,MKPC试件的硫酸根离子扩散系数逐步提高;浸泡360 d后,试件的硫酸根离子扩散系数为3.9×10^-7mm²/s,离表面2 mm处的硫酸根离子含量为0.218%（质量分数）。MKPC试件的强度随着浸泡龄期的延长先增大后减小,其发展规律和扩散系数变化规律一致。浸泡360 d后,MKPC试件的抗折和抗压强度损失率均小于5%。更多还原

【Abstract】 Through macro performance test, chemical analysis and microscopic analysis, this paper studied the diffusion of sulfate ions and strength development of magnesium potassium phosphate cement（ MKPC） specimens immersed in a Na₂SO₄ solution with a mass fraction of 5%. The results show that with the extension of soaking age, the content of sulfate ions inside the specimens and the depth of erosion gradually increases. The relationship between the depth of erosion of sulfate ions in MKPC specimens and the sulfate ion content generally fits a second-order or third-order polynomial（with a correlation coefficient R² greater than 0. 998）. By solving the analytical expression using Fick’s second law of diffusion with established boundary conditions, the diffusion coefficient of sulfate ions in MKPC specimens is in the range of 10^-7mm²/s,which is one order of magnitude lower than that of Portland cement concrete. The diffusion coefficient of sulfate ions in MKPC specimens exhibits a decreasing trend for soaking age not exceeding 180 d. After more than 180 d, the diffusion coefficient of sulfate ions in MKPC specimens gradually increases. After 360 d of soaking, the diffusion coefficient of sulfate ions in MKPC specimen is 3. 9 × 10^-7mm²/s, and the sulfate ion content at 2 mm from the surface is 0. 218%（mass fraction）. The strength of MKPC specimens increases initially and then decreases as the soaking age extends, following a similar trend to that of the diffusion coefficient of sulfate ions. After 360 d of soaking, the loss rates of flexural and compressive strength of MKPC specimens are both less than 5%.更多还原