化学激发剂对废弃粗粉煤灰火山灰活性的影响

Influence of Chemical Activators on the Pozzolanic Property of Reject Fly Ash

通过研究不同化学激发剂对废弃粗粉煤灰 -水泥系统的强度发展、水化程度、水化产物等的影响 ,发现掺入Na2 SO4 和 K2 SO4 可以大幅提高废弃粗粉煤灰 -水泥系统在早期和晚期的抗压强度 ,而掺入 Ca Cl2 和 Ca(OH) 2 的效果则不明显 ,X射线衍射的测试结果也证明了这一点。由此说明化学激发废弃粗粉煤灰的火山灰活性重点在于提高系统的p H值。另外 ,水化程度测试的结果显示 ,化学激发剂对粗粉煤灰的促进作用主要集中在 2 8d以前。

Compared with the influence of different chemical activators on the strength development, hydration degree of reject fly ash and hydration products, it can be found that the addition of Na 2SO 4 and K 2SO 4 can significantly increase the compressive strength at both early and later curing ages. But the addition of CaCl 2 and Ca(OH) 2 shows little effect on the strength development. It can be supported by the results of X-ray diffraction. This means that the key of activating the reject fly ash is to elevate the pH value of the reject fly ash-cement system. The results of hydration degree show that chemical activators mainly take effect on the reaction of reject fly ash before 28 days.