为了获得溶蚀与氯盐耦合作用下水泥基材料性能退化规律,设计开展了硬化水泥净浆试件在1.0mol/L Na Cl、1.0mol/L NH_4Cl及1.0mol/L NaCl+3.0mol/L NH_4NO_3混合溶液中的浸泡腐蚀试验,并利用酚酞法、饱和干燥称重法、快速氯离子浓度测定仪和X射线衍射仪(XRD)对腐蚀进程中硬化水泥净浆溶蚀深度、孔隙率、自由氯离子含量及物相组成进行分析。结果表明,腐蚀过程中硬化水泥净浆溶蚀深度与时间平方根成线性关系;硬化水泥净浆孔隙率及氯离子传输速率均随着氢氧化钙的溶出而不断增加,一旦氢氧化钙完全溶出,其基本保持不变;钙离子的不断溶出,导致硬化水泥净浆内部化学环境发生改变,原有的结合氯离子变成自由氯离子。
In order to obtain the degradation of cement-based materials under the coupling interactions of calcium leaching and chloride erosion, the immersion corrosion test of cement paste specimens in three leaching solutions (1.0mol/L NaCl, 1.0mol/L NH6Cl, 1.0mol/L NaCl and 3.0mol/L NH4NO3) was carried out. The leaching depth, porosity, free chloride content and phase composition of cement paste in the process of calcium leaching and chloride erosion were investigated by the phenolphthalein "method, saturation-drying weighing method, rapid determination method of chloride ion content and X-ray diffraction analysis (XRD). The results show that the leaching depth of cement paste is linear with the square root of time. The porosity and chloride transmission rate of cement paste all increase with the dissolution of calcium hydroxide, and once the calcium hydroxide completely dissolves, it basically remains unchanged. Moreover, the continuous dissolution of calcium ions results in a change in the chemical environment within the cement paste, where the original bound chloride ion becomes to a free chloride ion.