沸石粉对硫铝酸盐水泥水化行为的影响机理研究

研究了沸石粉对硫铝酸盐水泥浆体流动度、凝结时间和抗压强度的影响规律,并通过自收缩、电阻率和XRD测试分析了沸石粉在硫铝酸盐水泥水化行为中的作用机理。结果表明,掺入沸石粉后水泥浆体的流动度明显降低,凝结时间显著延长,且延长时间随掺量的增大呈先增大后减小的趋势。当沸石粉掺量为5%~15%(质量分数)时,硬化水泥浆体的1 d、3 d、7 d抗压强度均有显著提高;沸石粉掺量为10%时,水泥浆体3 d、7 d、28 d的强度增长幅度最大,和空白组相比,分别增长了21.6%、13.9%和5.4%。掺入沸石粉后水泥浆体的24 h电阻率显著增大,硬化浆体的7 d自收缩减小,且在相同龄期时,硬化浆体的自收缩随沸石粉掺量的增大而减小。XRD分析显示沸石粉的掺入能有效促进硫铝酸盐水泥的水化,有利于1 d、3 d和28 d龄期内钙矾石的形成。

Effect of Zeolite Powder on Hydration Behavior of Calcium Sulfoaluminate Cement

The effects of zeolite powder on fluidity, setting time and compressive strength of calcium sulfoaluminate cement pastes were studied, and the mechanism of zeolite powder in the hydration behavior of calcium sulfoaluminate cement was analyzed by autogenous shrinkage, electrical resistivity and XRD. The results show that the fluidity of the cement paste decreases obviously with the addition of zeolite powder, and the setting time increases significantly, and then increases slowly with the increase of zeolite powder. When the zeolite powder mass content is from 5% to 15%, the compressive strength of hardened cement paste at 1 d, 3 d and 7 d increases significantly. When the zeolite powder mass content is 10%, the compressive strength of cement paste at 3 d, 7 d and 28 d increases by 21.6%, 13.9% and 5.4%, respectively, compared with the control group. After adding zeolite powder, the electrical resistivity of cement paste at 24 h increases significantly, and the autogenous shrinkage of hardened cement paste decreases at 7 d. At the same age, the autogenous shrinkage of hardened cement paste decreases with the increase of zeolite powder. XRD analysis shows that the addition of zeolite powder effectively promotes the hydration of calcium sulfoaluminate cement, and is beneficial to the formation of ettringite at 1 d, 3 d and 28 d ages.