水泥中S/Al和外渗硫酸盐对氯离子临界浓度的影响

Influences of S/Al of Cement and Sulfate in Extravasation Solution on Chloride Threshold Value

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摩尔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摩尔比的提高先增大后减少,而氯离子的结合量随S/Al摩尔比的提高而降低,氯离子临界浓度达最大值时的S/Al摩尔比随水泥中Al2O3含量的提高而降低;在SO24-和Cl-浓度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S/Al摩尔比的提高先增大后减少,且临界浓度低于NaCl溶液浸泡试件;复合渗透液中的SO42-渗透进砂浆使砂浆结构变致密,但过量后会引起体积膨胀,使氯离子临界浓度下降.

This paper deals with the influences of the S/Al molar ratio of cement and the sulfate in extravagation solution on the chloride threshold value via the linear polarization method,the mercury injection test and XRD.The results show that,with the increase of S/Al molar ratio,the chloride threshold value first increases and then decreases,while the chloride bounded in cement hydration products keeps reducing,that the S/Al molar ratio corresponding to the maximum chloride threshold value decreases with the increase of Al2O3 content of cement.More-over,it is also found that,when the specimens are immersed in the composite solution with the SO2-4 and Cl-concentrations similar to those of seawater,the chloride threshold value first increases and then decreases with the increase of S/Al molar ratio,but it is lower than that of the specimens immersed in NaCl solution,and that,with the penetration of SO2-4,the mortar first becomes denser and then presents a volume expansion due to an excessive penetration,thus resulting in the decrease in chloride threshold value.