摘要
【目的】改善宁夏地区工程盐渍土地基的冻胀和腐蚀问题。【方法】采用水泥、粉煤灰、硅灰和硅锰渣作为盐渍土的固化剂,设计四因素三水平正交试验方案,通过无侧限抗压强度试验和三轴试验,探讨不同固化剂掺量(质量分数,下同)对盐渍土抗压强度和抗剪强度的影响;采用扫描电子显微镜(scanning electronic microscopy,SEM)和X射线衍射(X‐ray diffraction,XRD)表征分析固化盐渍土的强度提升机制。【结果】水泥和硅灰提升固化盐渍土的早期强度作用较为显著,随掺量的增加,粉煤灰强度呈先增后减的趋势,硅锰渣结构较为稳定,需要充足的碱性环境来激发胶凝能力;水泥、粉煤灰、硅灰和硅锰渣4种因素对固化盐渍土抗压强度的影响程度由高到低的顺序为水泥、硅灰、粉煤灰、硅锰渣;水泥、粉煤灰、硅灰和硅锰渣掺量分别为3%、5%、5%和3%时固化效果最佳,为最佳配合比;固化盐渍土生成棒状的钙矾石(aluminate ferro-copper-calcium sulfate,AFt)和网状的水化铝酸钙(calcium aluminate hydrate,C-A-H)等水化产物相互联结,微观结构变得致密。协同作用提升了固化盐渍土的强度。【结论】采用水泥、粉煤灰、硅灰和硅锰渣最佳配合比能够使盐渍土地基固化,改善地基的冻胀和腐蚀问题。
Objective To address the frost heave and corrosion issues in engineering saline soil foundation in Ningxia,and to improve the comprehensive utilization of solid waste in the Ningxia Hui Autonomous Region,this study focuses on the analysis of the interaction of a composite curing agent used to solidify saline soil.Methods Every year,industrial areas in Ningxia Hui Autonomous Region produce a significant amount of solid waste,including fly ash,silica fume,and silicon manganese slag.This waste exhibits good pozzolanic activity and can be effectively cured using alkali-activated materials.To this end,this paper employs cement,fly ash,silica fume,and silicomanganese slag as curing agents for saline soil.To comprehensively study the influence of mixed cement,fly ash,silica fume,and silicon manganese slag on the strength characteristics of solidified saline soil,we used an orthogonal test to design a four-factor three-level orthogonal test scheme.This method selects a representative experimental scheme from many experimental conditions,effectively solving the problem of many factors and a large number of tests.The experiment is discussed from two perspectives:macro mechanics and micro mechanism.The mechanical properties of solidified saline soil are verified using the unconfined compressive strength test and triaxial test.The influence of different curing agent content on the compressive strength and shear strength of saline soil is discussed.The strength improvement mechanism inside the solidified saline soil is characterized and analyzed using scanning electronic microscopy(SEM)and X-ray diffraction(XRD).The microstructure of cementitious materials,including particle size,shape,distribution,and surface characteristics,can be observed using the high-resolution ability of SEM.XRD is a powerful tool for identifying various crystal phases in cementitious materials and analyzing their crystal structure and phase composition.The microstructure,composition,and crystal structure information of the material can be analyzed mor
作者
王紫
周志尧
张喆
兰永军
孟松松
李宏波
WANG Zi;ZHOU Zhiyao;ZHANG Zhe;LAN Yongjun;MENG Songsong;LI Hongbo(College of Civil and Hydraulic Engineering,Ningxia University,Yinchuan 750021,China;Ningxia Water-saving Irrigation and Water Resources Regulation Engineering,Ningxia University,Yinchuan 750021,China;Ningxia Civil Engineering Earthquake Prevention and Disaster Mitigation Engineering Technology Research Center,Ningxia University,Yinchuan 750021,China;Department of Civil and Structural Engineering,University of Sheffield,South Yorkshire S102TN,UK)
出处
《中国粉体技术》
CAS
CSCD
2024年第5期57-69,共13页
China Powder Science and Technology
基金
国家自然科学基金项目,编号:52069025
宁夏回族自治区自然科学基金重点项目,编号:2023AAC02025
宁夏回族自治区高等学校一流学科(水利工程学科)资助项目,编号:NXYLXK2021A03。
关键词
固化盐渍土
无侧限抗压强度试验
三轴试验
微观分析
solidified saline soil
unconfined compressive strength test
triaxial test
microscopic analysis
