为降低膏体充填成本,提高粉煤灰利用率,以粉煤灰替代部分水泥作为膏体胶凝剂。通过化学方法激发粉煤灰活性,设计了激发剂选型实验和优化配比实验,研究了化学激发下掺粉煤灰膏体强度的变化规律,旨在解决掺粉煤灰膏体早期强度低的问题。结果表明:三乙醇胺、NaOH、CaO能有效提高粉煤灰活性,而Ca(OH)2、Na2SO4、CaSO4·2H2O和CaCl2对粉煤灰活性激发效果不明显。不同龄期三乙醇胺的最佳掺量一致,为粉煤灰质量的1.2%;Na OH激发时掺粉煤灰膏体不同龄期的强度随其掺量增加不断提高,掺量超过3%时,强度增长速度逐渐降低;不同龄期的CaO最佳掺量不一致,3 d最佳掺量为4%、7 d为2%、14 d和28 d为6%,CaO激发膏体后期强度不显著。
Replacing part of cement with fly ash as cementing agent of paste is adopted to reduce cost of paste backfill and improve utilization of fly ash.The activation of fly ash is raised by chemical methods,and experiments on the selection of activator and the optimization of the ratio are designed to investigate the rule of fly ash paste strength change by chemical activation research,aiming to solve the problems of the low early strength of fly ash paste.The results showed that:( a) The activity of fly ash was effectively improved by Triethanolamine,Na OH and Ca O,but changed less by Ca( OH)2,Na2SO4,Ca SO4·2H2O and Ca Cl2.( b) The optimal content of Triethanolamine is 1. 2% of the fly ash at different age of fly ash-paste.( c) Fly ash-paste strength of different age is increased with the content of Na OH,and its development rate gradually decreased when the content is more than 3%.( d) The optimal content of Ca O is different when the age of fly ash-paste is different,the optimal content of Ca O is 4% of fly ash in quality for 3 d,and 2% for 7 d,and 6% for 14 d and 28 d,later strength of paste with Ca O is not significant.