摘要
为改良低液限粉质黏土的力学与耐久性能,提出了以磷石膏-钢渣-矿渣(PSG,Phospogypsum-Steel slag-Ground granulated blast-furnace slag)为材料的全固废固化剂对低液限粉质黏土进行固化,并与同掺量的P.O 42.5普通硅酸盐水泥固化土进行对比。研究了不同PSG掺量(5%、10%、15%)和不同龄期对固化土无侧限抗压强度、劈裂强度、水稳定性、干缩变形和抗冻融循环能力的影响,并通过电镜扫描(SEM)和X射线衍射(XRD)分析了其微观固化机制。试验结果表明:随着固化剂掺量的增加,固化土的最大干密度增大,最优含水率减小。PSG固化土具有较高的后期强度和水稳性能,28d的抗压强度达到了5.28MPa,水稳系数达到93.5%。90d的累计失水量和干缩应变分别为71.3g和1.12×10^(-3),比水泥固化土的79.6g和1.28×10^(-3)降低了10.43%和12.5%。20次冻融循环后,PSG固化土的强度损失为21.65%,比水泥固化土的27.25%降低了5.6%。微观测试发现大量絮凝状C-S-H胶凝物质和针棒状AFt在PSG固化土中出现,这些物质通过填充孔隙、包裹土颗粒和搭接骨架,提高了土体的强度,增强了土体性能。
In order to improve the mechanical property and durability of low liquid limit silty clay,a full solid waste solidification agent,i.e.phosphogypsum-steel slag-ground granulated blast-furnace slag(PSG),was proposed to solidify low liquid limit silty clay.The PSG solidified silty clay was compared with the same soil stabilized by the P.O 42.5 ordinary Portland cement with the same content.The effects of PSG contents,i.e.5%,10%,15%,and solidified time on the unconfined compressive strength,splitting strength,water stability,dry shrinkage deformation,and freeze thaw resistance of the solidified soil were studied.To examine the micro mechanism of the solidified soil,the samples was tested by scanning electron microscopy(SEM)and X-ray diffraction(XRD).The experimental results showed that the maximum dry density of solidified soil increased and the optimal water content decreased with the increase of the content of solidified agent.PSG solidified soil had higher late strength and water stability performance,and the compressive strength of 28 d reached 5.28 MPa,and the water stability coefficient reached 93.5%.The cumulative water loss and dry shrinkage strain of 90 days were 71.3 g and 1.12×10^(-3),respectively,which were 10.43%and 12.5%lower than those of cement solidified soil of 79.6 g and 1.28×10^(-3).After 20 freeze-thaw cycles,the strength loss of PSG solidified soil was 21.65%,which lower than that of cement solidified soil by 27.25%.Microscopic tests showed that a large number of flocculated C-S-H cementitious substances and needle-like AFt appeared in PSG solidified soil,which improved the strength and performance of the soil by filling pores,wrapping soil particles and lapping skeleton.
作者
王应富
张树光
黄啸
李江山
刘磊
王胜杰
程鑫
Wang Yingfu;Zhang Shuguang;Huang Xiao;Li Jiangshan;Liu Lei;Wang Shengjie;Cheng xin(Guilin University of Technology,Guilin,541004,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China;Hubei Province Key Laboratory of Contaminated Sludge and Soil Science and Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2023年第S01期12-23,共12页
China Civil Engineering Journal
基金
中国科学院国际合作重点项目(115242KYSB20200002)
内蒙古自治区科技计划(2022YFHH0075)
国家自然科学基金青年科学基金项目(42007260)
关键词
低液限粉质黏土
全固废固化剂
力学性能
耐久性能
固化机制
low liquid limit silty clay
full solid waste solidified agent
mechanical properties
durability
solidified mechanism
