盐溶液中ECC氯离子侵蚀规律及结构变化

ECC chloride ion erosion and structure changes in salt solution

通过对超高韧性水泥基材料(ECC)试件进行氯离子的扩散试验,研究了水胶比、侵蚀时间、氯盐浓度等变量对ECC材料中氯离子传输规律的影响。揭示氯离子浓度分布规律与侵蚀深度,分析了腐蚀前后水泥浆体孔隙结构及物相变化。结果表明:氯离子侵蚀深度随时间增加逐渐增大,且呈现出先快速增长后缓慢增长趋势;水胶比和氯盐浓度越大,氯离子侵蚀越严重;氯离子侵蚀前后,ECC材料的物相组成和孔结构都发生了显著变化,具体表现在氯离子侵蚀后在基体内部形成Friedel盐填充了基体部分孔隙,降低了基体孔隙率,改善了ECC材料的孔结构。

Through the chloride ion diffusion test of ultra-high toughness cement-based materials(ECC), the effects of water-binder ratio, erosion time and chloride concentration on chloride ion transport in ECC materials were studied. The distribution law of chloride ion concentration and erosion depth were revealed, and the pore structure and phase changes of cement paste before and after corrosion were analyzed. The results show that the depth of chloride ion erosion increases gradually with the increase of time, and shows a trend of rapid growth at first and then slow growth, and the higher the ratio of water to binder and the concentration of chloride salt, the more serious the chloride ion erosion. Before and after chloride ion erosion, the phase composition and pore structure of ECC materials have changed significantly, which is manifested in the formation of Friedel salt inside the matrix after chloride ion, which fills part of the pores of the matrix, which reduces the porosity of the matrix and improves the pore structure of ECC materials.