AMC固化高液限黏土的强度及孔隙特征研究  

Research on strength behavior and micro-mechanism of AMC stabilized high liquid limit clay

作　　者：郭乾 魏明俐[2] 杜广印[1] 薛皓辰 刘松玉[1] GUO Qian;WEI Mingli;DU Guangyin;XUE Haochen;LIU Songyu(Institute of Geotechnical Engineering,Southeast University,Nanjing,Jiangsu 210096,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China)

机构地区：[1]东南大学岩土工程研究所,江苏南京210096 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071

出　　处：《中国矿业大学学报》2018年第4期838-845,共8页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(41372308);国家自然科学基金青年科学基金项目(41702349)

摘　　要：水泥作为目前主要的固化剂,由于其生产过程能耗大、碳排放高,且使用水泥土搅拌桩法固化软弱地基土时,表现出强度提升有限与早期强度增长缓慢,上述特性不符合我国现代化基础设施建设的发展需求.为了减少碳排放量,提高治理效果,采用NaOH溶液、偏高岭土(MK)和水泥制备了新型碱激发胶凝材料(AMC).通过无侧限抗压强度、MIP压汞和SEM扫描电镜试验对AMC固化高液限黏土的强度和孔隙变化特征进行了分析.结果表明:AMC固化土28d强度较水泥固化土提高了68.0%,较MC固化土(MK作为分散剂)提高了64.0%~123.8%,且后者随着偏高岭土替换率λ增加而呈逐渐上升趋势;λ对AMC固化土孔隙影响显著,当λ从10%增长到20%时,AMC固化土的中小孔隙体积减少28.1%,微孔隙体积增加47.5%;AMC固化土中水泥基凝胶材料以无定形形态为主,填充效果好,且孔隙分布更加均匀,而MC固化土水化产物以棒状产物为主,填充效果较差.Due to the insignificant strength improvement and serious energy consumption,the common binder of Portland cement is difficult to reach the requirement of the rapid development of modern constructions.To reduce the CO2 emission and improve the performance of stabilized soil,a new alkali-activated material（AMC）mixed with NaOH solution,metakaolin（MK）and cement was prepared.The strength charateristics and pore volume distribution of the AMC stabilized high liquid limit clay were studied using the unconfined compressive strength test,the mercury intrusion porosimetry（MIP）technology and the scanning electron microscopy（SEM）method.The results show that the strength of AMC stabilized soil was 68.0% higher than that of cement,and about 64.0%—123.8% higher than that of MK blended cement（MC）;the latter one was kept rising gradually with the increase of the substitution ofMK（λ）.A significant impact ofλwas also observed on the pore distribution of AMC stabilized soil.Whenλwas increased from 10% to 20%,the pore volume was reduced by 28.1%,and the microporous volume was increased by 47.5%.The cementitious gels observed in AMC stabilized soil were mainly amorphous and the microporous distribution was more uniform,whereas the filling effect was relatively low with the bar-based products in the MC stabilized soil.

关 键 词：高液限黏土 碱激发材料 高Ca-Si-Al系统 无侧限抗压强度 微观机理 

分 类 号：TU411[建筑科学—岩土工程]