碳酸盐溶液中富水充填材料的腐蚀及劣化机理

为了研究碳酸根离子对富水充填材料的影响，通过强度检测、扫描电镜观察、X射线衍射分析和红外光谱测试，分析富水充填材料在碳酸钠溶液中浸泡后的宏观及微观结构变化，并对其腐蚀及劣化机理进行探讨.富水充填材料在质量分数为10%的碳酸钠溶液中浸泡后，抗压强度随浸泡时间延长大幅度降低，浸泡90 d 后抗压强度比标养28 d 抗压强度降低72.5%，浸泡28 d后出现泥化现象. X射线衍射图谱显示，富水充填材料在质量分数为10%的碳酸钠溶液中浸泡后有碳硫硅钙石生成，且随浸泡时间延长碳硫硅钙石的生成量增大.红外光谱结果未发现 AlO6]存在，证实在碳酸钠溶液中富水充填材料硬化体中钙矾石急剧减少，转变为烂泥状的碳硫硅钙石；碳硫硅钙石作为无胶结力物质，会对富水充填材料硬化体造成严重破坏，表明碳酸盐溶液对富水充填材料具有腐蚀作用.

Corrosion and deterioration mechanism of water-rich filling materials in carbonate solutions

In order to research the impact of carbonate ions on water-rich filling materials, strength testing, scanning electron microscopy, X-ray diffraction analysis and IR spectrum testing were used to analyze the macro- and micro-structural change and the corrosion and deterioration mechanism of the materials in sodium carbonate solutions. It is found that the compressive strength of the materials in a sodium carbonate solution whose mass fraction is 10% decreases significantly with increasing soaking time. When the soak age is 90 d, the compressive strength of the materials decreases by 72. 5% compared with standard curing for 28 d. After soaking for 28 d the specimen surface is muddy. XRD patterns show that after soaking in a sodium carbonate solution whose mass fraction is 10%, thaumasite generates in the materials. With increasing soaking time the amount of thaumasite increases. Infrared spectroscopy results show that there does not exist AlO6 ] . This confirms that ettringite in the materials soaking in the sodium carbonate solution drastically reduces and transforms into pulpy thaumasite. As non-cemented materials, thaumasite will cause serious damage to the hardening body of the materials. This shows that the carbonate solution has corrosive action on water-rich filling materials.