氯离子对碳硫硅钙石形成的影响

Effect of Chloride Ions on Thaumasite Formation

研究了氯离子对碳硫硅钙石形成的影响,将水泥–石灰石粉净浆样品浸泡在(5±2)℃不同质量分数的NaCl/Na2SO4复合溶液中,观察侵蚀后样品的外观,并对腐蚀产物进行X射线衍射、红外光谱分析。结果表明:纯Na2SO4溶液中的样品发生碳硫硅钙石型硫酸盐侵蚀,腐蚀产物以碳硫硅钙石及石膏为主,随着时间的延长而日益严重,由表及里逐渐变为一种无胶凝性的烂泥状物质。NaCl/Na2SO4复合溶液中样品的硫酸盐侵蚀程度和腐蚀产物中碳硫硅钙石量随氯离子浓度的提高而逐渐降低。氯离子减缓了碳硫硅钙石的形成速度,并且氯离子浓度越高减缓效果越显著。

A thaumasite form of sulfate attack accelerated test was carried out to investigate the effect of chloride ions on thaumasite formation.Cement-limestone powder paste samples were immerged in NaCl/Na2SO4 composite solution at different concentrations.The appearance of corroded samples was observed.Besides,the corrosion products were also analyzed by X-ray diffraction and in-frared spectrum methods.The results show that the sample immerged in pure Na2SO4 solution occurs serious thaumasite form of sul-fate attack after 12 months immersion,and the corrosion products are mainly thaumasite and gypsum.The damage got more and more serious,and the sample finally became a no-cementitious mud-like material from the outside to the inside with time.However,the corrosion degree of samples and thaumasite content of corrosion products both decreased with increasing the chloride ions concentra-tion of NaCl/Na2SO4 composite solution.Chloride ions can slow thaumasite formation speed,and the higher the concentration of chlo-ride ions is,the slower the effect of chloride ions on thaumasite formation.