碳硫硅酸钙型硫酸盐侵蚀测试方法

Test methods for thaumasite form of sulfate attack

碳硫硅酸钙和钙矾石有着很相似的晶体结构及形貌,常规测试中容易将二者混淆.在分析二者物相结构的基础上,介绍和评价了电子显微分析和成分分析、X射线衍射分析、红外和拉曼光谱分析、热分析、核磁共振等测试方法在碳硫硅酸钙型硫酸盐侵蚀研究中的应用特点和不足.电子显微分析和成分分析的结合以及单一的热分析能初步判定腐蚀产物中碳硫硅酸钙的存在,X射线衍射分析很难区分二者,红外、拉曼光谱以及核磁共振能确定硅氧八面体的存在,从而证明存在碳硫硅酸钙,因此研究中宜采用多种测试方法.

During many test methods, it is very difficult to identify thaumasite from deteriorated compound because the crystal structure and morphology of ettringite and thaumasite are strongly similar. This paper compares the crystal structure and morphology of ettringite and thaumasite in detail, reports and evaluates commonly used methods in study of thaumasite form of sulfate attack respectively, which include electron microscopy and electron probe micro-analyzer, X-ray diffraction, infrared spectrometer and Raman chemical imaging, differential scanning calorimetry, nuclear magnetic resonance, etc. E-lectron microscopy and electron probe micro-analyzer, differential scanning calorimetry can conform the presence of thaumasite. X-ray diffraction cannot determine the two phases exactly. Infrared spectrometer and Raman chemical imaging, as well as nuclear magnetic resonance can conform octahedrally coordinated SiO6 units, which belongs to the thaumasite. Several methods should be used in the study of this type of sulfate attack.