水泥稳定碱渣改性土冻融性质与劣化机理
Freeze-thaw Resistance and Deterioration Mechanism of Cement-treated Mixture of Soda Residue and Clay
赵晓晴 1沈泽宇 2邓永锋 3李家伟 1岳志才 4梁腾2
作者信息
- 1. 江苏海洋大学土木与港海工程学院,江苏连云港 222005;江苏省海洋工程基础设施智能建造工程研究中心,江苏连云港 222005;江苏省海洋资源开发研究院(连云港),江苏连云港 222005
- 2. 江苏海洋大学土木与港海工程学院,江苏连云港 222005;江苏省海洋工程基础设施智能建造工程研究中心,江苏连云港 222005
- 3. 东南大学交通学院,江苏南京 210096
- 4. 中交一公局第三工程有限公司,北京 101102
- 折叠
摘要
为明晰水泥稳定碱渣改性土在季冻区应用可行性,研究了位于毛细水浸润线上、下层位水泥稳定碱渣改性土抵抗冻融循环的性能.设置干侧、湿侧2种不同的冻融循环条件,分别进行0～8次冻融循环试验.探究了水泥稳定碱渣改性土体积、质量和表观现象在冻融循环试验过程中的变化,以及不同冻融循环次数后其抗压强度和含水率的演变,并结合SEM电镜结果分析其冻融劣化机理.研究结果表明:干侧冻融试样体积表现为"冻缩融胀",整体体积变化小;质量总体呈下降趋势,整体质量变化小;强度逐渐下降,8次循环后抗压强度损失率为81.6％;水分向试样内部迁移,中心处含水率升高0.72％;表观劣化较弱.湿侧冻融试样体积表现为"冻胀融缩",8次循环后膨胀5.45％;质量总体损失较大,8次循环后损失2.87％;试样强度逐渐下降并趋向稳定,抗压强度损失率最终保持在65％;水分向试样外侧迁移,中心处含水率下降2.57％;表观裂隙和剥落情况明显.湿侧冻融试样劣化程度大于干侧试样.水泥稳定碱渣改性土较好的抗冻融性能来源于其较强的密实特性,黏土填充碱渣的空间骨架,水泥水化物进一步加强土体颗粒的联结.在冻融循环作用下,试样中水分迁移和固/液两相往复转化对水泥稳定碱渣改性土微观结构产生了明显破坏.为此,在季冻区毛细水浸润线以上层位使用水泥稳定碱渣改性土具有较好的稳定性.
Abstract
To promote the engineering application of cement-treated mixtures of soda residue and clay(CMSRC)in seasonal freezing regions,the freeze thawing(F-T)resistance of CMSRC,located above or below the saturation line of the capillary water,was investigated in this study.Accordingly,two kinds of dry and wet F-T cycle conditions were set,and experiments including 0-8 F-T cycles were conducted.Changes in the volume,mass,and appearance of CMSRC during the F-T cycles,as well as the evolution of the unconfined compressive strength(UCS)and water content after different F-T cycles were explored.The deterioration mechanism of F-T cycles was analyzed via scanning electron microscopy.Under 8 cycles of dry F-T,the volume exhibited freeze shrinkage and thaw expansion,with a small overall change;the mass generally presented a downward tendency,with a small change in overall quality;the UCS gradually decreased,and the bearing damage ratio(BDR)was 81.6％after 8 cycles.The water migrated inward,with 0.72％increase in water content at the center,and the appearance remained almost unchanged.However,under 8 cycles of wet F-T,the volume demonstrated freeze expansion and thaw shrinkage,expanding 5.45％after 8 cycles.The mass loss was significant,of 2.87％after 8 cycles;the UCS gradually decreased then stabilized,and the BDR was approximately 65％;the water migrated outward with 2.57％decrease in water content at the center,the surface cracks grew and peeling developed gradually.The better F-T resistance of CMSRC is due to its strong density,with the spaces in the SR filled with clay,and cement hydrate further strengthening the connection of soil particles.Under the action of F-T cycles,water migration and cycled phase conversion significantly damaged the microstructure of CMSRC.Thus,it is recommended that CMSRC can be used above the vadose zone in the seasonal frozen region.
关键词
路基工程/劣化机理/冻融循环/水泥稳定碱渣改性土/物理性质/强度性质Key words
subgrade engineering/deterioration mechanism/freeze-thaw cycle/cement-treated mixture of SR and clay/physical property/strength performance引用本文复制引用
基金项目
国家自然科学基金项目(42272322)
国家自然科学基金项目(51809101)
江苏高校青蓝工程资助性项目()
江苏省重点研发计划(BE2021681)
出版年
2024
NETL
NSTL
维普
万方数据