硫酸盐对石膏复合胶凝材料水化进程的激发作用研究

Activating Effect of Sulfates on the Hydration Process of Gypsum Composite Binder

采用KAl(SO4)2·12H2O和Al2(SO4)3·18H2O为激发剂,研究硫酸盐激发剂对石膏复合胶凝材料(GCB)凝结时间、力学性能和耐水性的影响,用SEM和XRD分析硫酸盐在GCB中的作用及其影响机理。结果表明,GCB的主要水化产物是钙矾石和C-S-H凝胶,硫酸盐有利于钙矾石和C-S-H凝胶的生成。两种硫酸盐都能显著提高GCB的早期强度,改善其泌水和耐水性能;达到最佳掺量1%时,KAl(SO4)2·12H2O的激发效果更好,GCB试样7 d抗压强度为24.7 MPa,软化系数大于0.9。

The effect of sulfate activators on setting time, mechanical properties and water resistance of gypsum composite binder（GCB） is investigated by KAl（SO4）2· 12H2 O and Al2（SO4）3· 18H2 O as activator, the effect and influence mechanism of sulfates in GCB are analyzed by SEM and XRD. The results show that main hydration products of GCB are ettringite and C-S-H gel, sulfates accelerate formation of ettringite and C-S-H gel. Two kinds of sulfates can significantly increase the early strength of GCB, improve its bleeding and water resistance, KAl（SO4）2· 12H2 O has better activating effect on the optimal dosage of 1%, compressive strength of the GCB sample is 24.7 MPa in 7 d, the softening coefficient above 0.9.