机械粉磨对岩土固化用无熟料胶凝材料性能的影响

Effect of mechanical grinding on properties of the cementitious materials without clinker for soil solidification

利用稻壳灰、CFB脱硫灰、钢渣协同制备一种无熟料水硬性无机胶凝材料,可替代水泥用于岩土固化。为提高这种胶凝材料的活性及其他性能,研究经机械粉磨后胶凝材料的性能变化及其机理。结果表明:随着粉磨时间增加,胶凝材料的粒度分布曲线由多峰分布转变为单峰分布,标准稠度用水量减少,凝结时间缩短;水化诱导期的结束时间和第2放热峰出现时间明显提前,累积放热量增加;砂浆试件的早期抗压强度和自收缩显著增加;采用无熟料胶凝材料制备流态固化土,其初始流动扩展度随粉磨时间增加而增加,经时损失加快;机械粉磨对固化土的早期强度影响不显著,后期强度则呈现先增加后降低的趋势。采用该无熟料胶凝材料制备流态固化土,能满足一般回填工程的强度要求。

A hydraulic cementitious material was prepared by using rice husk ash,CFB desulfurization ash and steel slag,which can replace cement for soil solidification.In order to improve the activity and other properties of this cementitious material,the performance change and mechanism of the clinkerless cementitious material after mechanical grinding were studied.The results show that with the increase of grinding time,the particle size distribution curve of the cementitious materials changes from multi-peak distribution to single-peak distribution,the water consumption of standard consistency decreases and the setting time shortens.The end time of the hydration induction period and the appearance time of the second exothermic peak were significantly advanced,and the cumulative heat release increased.The early compressive strength and autogenous shrinkage of mortar specimens increased significantly.The initial flow expansion degree of the fluidized solidified soil prepared by the cementitious materials increases with the increase of grinding time,and the time-dependent loss accelerates.Mechanical grinding had no significant effect on the early strength of the solidified soil,while the later strength increases first and then decreases.Using this cementitious material without clinker to prepare fluidized solidified soil can meet the strength requirements of general backfill projects.