低温硫酸盐侵蚀环境中水泥石腐蚀产物

研究了水胶比为0.45,掺35%石灰石粉水泥基材料标准养护28d后在(5±2)℃浸泡于SO2-4质量分数为3.38%的钠盐、镁盐、铝盐3种硫酸盐侵蚀溶液中15周时的破坏状况和强度损失率.采用Fourier红外光谱、X射线衍射、扫描电子显微镜、能谱以及Raman光谱确定水泥石腐蚀物相和组成.结果表明:镁盐溶液中试件抗压强度损失率最大,其次是钠盐溶液中试件,铝盐溶液中试件抗压强度损失率最小;钠盐溶液和铝盐溶液中水泥石主要腐蚀产物是钙矾石和石膏;镁盐溶液中水泥石主要腐蚀产物是钙矾石、石膏、碳硫硅酸钙和少量水镁石.

EROSION SUBSTANCE OF CEMENT-BASED MATERIAL IN SULFATE ATTACK ENVIRONMENT AT LOW TEMPERATURE

Cement-based material made at a water-binder ratio of 0.45, with 35% cement replacement ratio by limestone powder were cured under standard conditions for 28d and then immersed in three kinds of sulfate solutions (Na2SO4, MgSO4, Al2(SO4)318H2O) with 3.38% mass fraction of SO2-4 for 15 weeks at (5±2)℃. Exterior attack and ratio of compressive strength loss were studied, and ero-sion substances of cement-based material were investigated by means of Fourier transform infrared spectroscopy, X-ray diffraction,scanning electron microscopy, and energy dispersive spectrum as well as Raman spectra. The results show that the ratio of compres-sive strength loss in MgSO4 solution is the greatest, and that in Al2(SO4)318H2O solution is the lowest among these three kinds of sulfate solutions. In Na2SO4 and Al2(SO4)3?18H2O sulfate solutions, the main erosion substances are ettringite and gypsum. And in MgSO4 sulfate solution the main erosion substances are ettringite, gypsum, thaumasite and brucite.