柠檬酸对阿利特-硫铝酸盐水泥凝结时间及水化过程的影响

Influence of citric acid on setting time and hydration of alite calcium sulfoaluminate cement

研究了柠檬酸对阿利特-硫铝酸盐水泥(ACSA)的凝结时间及水化过程的影响。研究结果表明:当柠檬酸的掺量在0.1%以下时,能够使得C3S的水化放热峰前移,对ACSA起促凝作用,且其1、3 d强度较空白样稍有提高;当掺量大于0.1%时,能够使得C3S的水化放热峰后移,延缓C3S的水化,且随着掺量的增加其缓凝作用愈加显著。当柠檬酸掺量达到0.3%时,凝结时间可达到113 min,较空白样提高了45%,且其1、3 d的净浆抗压强度与P·II 52.5水泥相当;当柠檬酸掺量达到0.6%时,凝结时间可达到283 min,但此时的1 d强度为零;柠檬酸能够延缓CH的生成,也能促进AFt的生成,同时柠檬酸的加入还能在一定程度上促进AFt向AFm的转化。

It studied the influence of citric acid on setting time and hydration of alite calcium sulfoaluminate cement.The results show that when the content of citric acid is less than 0.1%,the hydration exothermic peak of C3S appears early,and the setting time has been shortened,the compressive strength of 1d and 3d are improved.When the content is more than 0.1%,the hydration exothermic peak of C3S is delayed,and the hydration of C3S has been put off. With the increase of citric acid,the effect of retarding is more and more obvious. When the content of citric acid is 0.3%,the setting time is up to 113 min and the setting time is improved 45%,the compressive strength of 1d and 3d are equal to P-Ⅱ 52.5;When the content of citric acid is 0.6%,the setting time is up to 283 min,the compressive strength of 1 d is 0 MPa;Citric acid can delay the generation of CH,and also can promote the generation of AFt,while citric acid can promote AFt con-version to AFm.