活化煤矸石粉对砒砂岩水泥复合土强度影响的试验研究  

Effect of Activated Gangue Powder on the Strength of Pisha Sandstone Cement Composite Soil

作　　者：李大虎 李晓丽[1] 赵晓泽 郭长旭 LI Dahu;LI Xiaoli;ZHAO Xiaoze;GUO Changxu(College of Water Conservancy and Civil Engineering,Inner Mongolia Agricultural University,Hohhot 010018,China)

机构地区：[1]内蒙古农业大学水利与土木建筑工程学院,呼和浩特010018

出　　处：《材料导报》2025年第9期116-121,共6页Materials Reports

基　　金：国家自然科学基金(51869022);内蒙古自然科学基金(2020MS05051)。

摘　　要：煤矸石的活性低,利用难度大。对此,本工作通过煅烧的方式提高煤矸石粉的火山灰活性,将其作为辅助胶凝材料用于砒砂岩水泥复合土的制备。借助X衍射、热重、红外和核磁等试验方法,首先对比了煅烧前后煤矸石粉-砒砂岩水泥复合土的抗压强度,分析了煤矸石粉对复合土水化产物及微观孔隙的影响。然后探究了煅烧温度对煤矸石粉的影响,分析了煤矸石的活化机理。结果表明:煅烧处理可促使煤矸石粉中的高岭石向偏高岭土转化及煤矸石粉中所含碳的脱去,进而提高其火山灰活性。其中经600℃煅烧后的煤矸石粉活性最高,可促进复合土内部更多C-S-H、C-A-S-H凝胶的产生,使强度增加;随着煤矸石粉量的增加和水泥含量的相对降低,最终使得复合土内产生的凝胶含量减少,导致其强度下降。当煤矸石粉煅烧温度为600℃,掺量为5%时,煤矸石粉-砒砂岩水泥复合土的孔隙度为2.322%,小孔占比与束缚流体饱和度分别为64.45%和56.246%,且7 d强度满足二级及二级以下公路底基层的强度要求,该研究可为煤矸石粉-砒砂岩水泥复合土在道路铺设中的应用提供参考。The volcanic ash activity of coal gangue is extremely low,which limits its use as an auxiliary cementitious material for the preparation of Pisha sandstone cement composite soil.Therefore,this study aimed to improve the volcanic ash activity of gangue powder through calcination.First,the compressive strength of activated coal gangue-Pisha sandstone cement composite soil before and after calcination treatment was compared using X-ray diffraction,thermogravimetry,infrared and nuclear magnetic resonance,and other experimental methods.Furthermore,the influence of gangue powder on the hydration products and microscopic pores of the composite soil was analyzed.Second,the effect of calcining temperature on coal gangue powder was explored,and the activation mechanism of coal gangue was analyzed.The results showed that the calcination treatment can promote the conversion of kaolinite to metakaolin and the removal of carbon from gangue powder,thereby improving its volcanic ash activity.The gangue powder has the highest volcanic ash activity after calcination at 600℃,promoting the generation of more C-S-H and C-A-S-H gels inside the composite soil to increase its strength.However,increasing the amount of gangue powder and decreasing the cement content lead to a less gel content in the composite soil,which result in a decrease in its strength.With an addition of 5%gangue powder calcinated under 600℃,the porosity of gangue powder-Pisha sandstone cement composite soil was 2.322%,and the proportion of small pores and the saturation degree of bound fluid were 64.45%and 56.246%,respectively.Additionally,the 7 d strength of the composite soil meets the strength requirement for secondary road paving at the sub-base level and less than secondary highway.This study can provide a reference for the application of gangue powder-Pisha sandstone cement composite soil in road paving.

关 键 词：煤矸石粉 煅烧 砒砂岩 复合土 微观孔隙 

分 类 号：TU525[建筑科学—建筑技术科学]