钢渣-煤矸石地聚合物固化黄土的力学特性评价与固化原理分析  

Evaluation of mechanical properties and analysis of solidification principles of loess solidified with steel slag-coal gangue geopolymer

作　　者：唐先习[1] 张徐军 李昊杰 TANG Xian-xi;ZHANG Xu-jun;LI Hao-jie(School of Civil Engineering,Lanzhou University of Technology,Lanzhou,Gansu 730050,China;College of Environmental Science and Engineering,Donghua University,Shanghai 201620,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050 [2]东华大学环境科学与工程学院,上海201620

出　　处：《岩土力学》2025年第4期1205-1214,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.11962016);中国铁路兰州局集团有限公司资助项目(No.LTKY2023036-1)。

摘　　要：近年来,西北地区极端降雨导致黄土路基边坡失稳滑坡现象多发,为解决此类工程事故,以钢渣(steel slag,SS)和煤矸石(coal gangue,CG)为原材料、水玻璃和脱硫石膏(desulfurization gypsum,DG)为活化剂制备了一种高强度的钢渣-煤矸石地聚物(steel slag-coal gangue geopolymer,SC-GP)来固化黄土。首先通过28d无侧限抗压强度(unconfined compressive strength,UCS)试验确定了SC-GP的最优配合比。然后以SC-GP的最优配合比制备不同养护龄期和SC-GP掺量的固化土试样,通过UCS试验、直剪试验、崩解试验、X射线衍射(X-ray diffraction,XRD)试验、扫描电子显微镜(scanning electron microscope,SEM)试验和压汞法(mercury intrusion porosimetry,MIP)等试验从宏观和微观两个方面研究养护龄期和SC-GP掺量对固化土力学性能的影响规律。结果表明:SC-GP的最优配合比SS:CG:DG为40:54:6,水玻璃模数为1.2,水玻璃掺量为22%。SC-GP可以显著提升黄土的力学性能,并有效减缓固化土在水中的崩解率。当养护龄期达到28d时,SC-GP掺量为20%的固化土UCS和黏聚力分别为359.09 kPa和112.76 kPa,分别是重塑黄土的3.45倍和2.3倍,且在300 min内固化土在水中几乎不发生崩解,崩解率不到1%。微观机制研究发现,SC-GP固化土中产生了许多C-S-H(水化硅酸钙)和C-A-S-H(水化硅酸铝钙)等胶凝物质;大孔径孔隙体积减小,而小孔径孔隙的体积相对增大。In recent years,extreme rainfall in the northwest region has led to frequent instability and landslides of loess subgrade slopes.To address these engineering accidents,a high-strength steel slag-coal gangue geopolymer(SC-GP)was developed to solidify loess,using steel slag(SS)and coal gangue(CG)as raw materials and water glass and desulfurization gypsum(DG)as activators.First,the optimal mix ratio of SC-GP was determined through unconfined compressive strength(UCS)tests after 28 days of curing.Then,solidified loess samples with different curing ages and SC-GP contents were prepared based on the optimal mix ratio of SC-GP.Macro-and micro-scale analyses were employed to investigate the influence of curing age and SC-GP content on the mechanical properties of the solidified loess,utilizing UCS,direct shear,disintegration,X-ray diffraction(XRD),scanning electron microscope(SEM),and mercury intrusion porosimetry(MIP)tests.The results indicate that the optimal mix ratio of SC-GP is SS:CG:DG at 40:54:6,with a water glass modulus of 1.2 and a water glass content of 22%.SC-GP significantly enhances the mechanical properties of loess and effectively reduces the disintegration rate of solidified loess in water.After 28 days of curing,the UCS and cohesion of solidified loess with 20%SC-GP content are 359.09 kPa and 112.76 kPa,respectively,which are 3.45 and 2.3 times higher than those of remolded loess.Moreover,the solidified loess hardly disintegrates within 300 minutes in water,with a disintegration rate of less than 1%.Microscopic studies reveal numerous C-S-H(calcium silicate hydrated)and C-A-S-H(calcium aluminate silicate hydrated)gelling materials.The volume of large pores in the solidified loess decreased,while the volume of small pores increased relatively.

关 键 词：地聚物 固化黄土 力学性能 微观机制 胶凝物质 孔隙体积 

分 类 号：TU444[建筑科学—岩土工程]