水泥中S/Al比和外渗硫酸盐对氯离子临界浓度影响研究

采用线性极化法、压汞法和X射线衍射分析等方法研究了外渗氯盐条件下水泥中S/Al比及外渗硫酸盐对氯离子临界浓度的影响，研究结果表明：氯离子临界浓度随水泥中S/Al比提高先增大后减少，而氯离子的结合量随S/Al比提高而降低，氯离子临界浓度最大值时的S/Al比随水泥中Al2O3含量的提高而降低，S/Al比和Al2O3含量对氯离子临界浓度的影响实质上是对砂浆孔隙结构的影响。在SO42-和Cl-含量与华南地区海水相近的复合渗透液中，氯离子临界浓度随水泥中的S/Al比提高而先增大后减少，且临界浓度约为NaCl溶液浸泡试件的70%。复合渗透液中的SO42-渗透进砂浆先会使砂浆结构变致密，然后才引起体积膨胀，提高水泥中的S//Al比可提高水泥中AFm的生成量，从而相对降低由于生成滞后钙矾石引起的体积膨胀。

Research on influence of S/Al ratio in cement and sulfate in extravasation solution on chloride threshold values for corrosion of steel

the influence of S/Al ratio in cement and the composite solution with SO42-/Cl-] ratio was 1/8 on the chloride threshold values were investigated by linear polarization method, MIP test and XRD test, respectively. The experimental results showed that the chloride threshold value increased first and then decreased, but the chloride bounded in cement hydration products decreased with increasing the S/Al ratio in cement, and the S/Al ratio which corresponding the maximum chloride threshold value decreased with increasing the Al2O3 content in cement. The effect of S/Al ratio and Al2O3 content on the pore structure of mortars was essentially the influence on the chloride threshold value. When specimens immersed in composite solution which contains similar concentration of SO42- and Cl- with seawater. The chloride threshold value increased first and then decreased with increasing the S/Al ratio when the SO42-/Cl-] ratio was 1/8 in the solutions, but the values reduced to 70% compared with the specimens immersed in NaCl solution. With the SO42- penetrated into the structures, it made the mortars become more dense first and then caused the volume expansion. The production of AFm increased with increasing the S//Al ratio in cement, which may reduced the volume expansion by the formation of delayed AFt.