摘要
通过无侧限抗压强度试验、直接剪切试验研究了锂渣取代率、养护龄期对水泥土强度的影响,并利用扫描电镜(SEM)测试分析了锂渣水泥土的强度发展机理.试验结果表明:锂渣水泥土的无侧限抗压强度及抗剪强度均随着锂渣取代率的增加先升高后降低,最优取代率为18.75%;在养护龄期7 d时,相比纯水泥土,取代率为18.75%的锂渣水泥土的无侧限抗压强度及抗剪强度分别提升37.76%和9.26%(法向应力为400 kPa);养护龄期对锂渣水泥土的无侧限抗压强度和抗剪强度有显著影响,在18.75%取代率下,28 d相较于7 d的无侧限抗压强度和抗剪强度分别提高了80.26%和34.22%(法向应力为400 kPa);黏聚力随着锂渣取代率的增加呈现出显著的先升高后降低的规律,而内摩擦角随着锂渣取代率的增加变化不大.SEM测试从微观层面较好地解释了强度试验结果,在适当的锂渣取代率下,一次水化产物Ca(OH)_(2)和C-A-H凝胶发生的二次水化反应增加了胶凝物质和钙矾石,使得锂渣水泥土的微观结构得到了优化和改善.研究结果可为锂渣水泥土在公路工程中的应用提供参考.
The effects of lithium slag replacement rate and curing age on the strength of cement-soil were studied through unconfined compressive strength tests and direct shear strength tests.Scanning Electron Microscopy(SEM)was used to analyze the strength development mechanism of lithium slag cement-soil.The test results show that the unconfined compressive strength and shear strength of lithium slag cement-soil first increase and then decrease with the increase of lithium slag replacement rate,reaching an optimal replacement rate of 18.75%.At 7 days of curing,compared to pure cement-soil,the unconfined compressive strength and shear strength(normal stress of 400 kPa)of lithium slag cement-soil with a replacement rate of 18.75%increase by 37.76%and 9.26%,respectively.The curing age has a significant effect on the unconfined compressive strength and shear strength of lithium slag cement-soil.At a replacement rate of 18.75%,the unconfined compressive strength and shear strength(normal stress of 400 kPa)at 28 days are 80.26%and 34.22%higher than those at 7 days,respectively.The cohesion shows a significant trend of first increasing and then decreasing with the increase of lithium slag replacement rate,whereas the internal friction angle changes little with the increase of lithium slag replacement rate.The SEM analysis well explains the conclusions of the strength tests from a microscopic perspective.At an appropriate lithium slag replacement rate,the secondary hydration reaction between the hydration products Ca(OH)_(2) and calcium aluminate(C-A-H)of lithium slag and cement increases,resulting in more cementitious substances and calcium,thereby optimizing and improving the microscopic structure of lithium slag cement-soil.The research results can provide a refe-rence for the application of lithium slag cement-soil in high way engineering.
作者
周恩全
周旭鑫
王龙
ZHOU Enquan;ZHOU Xuxin;WANG Long(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang,Jiangsu 212013,China;School of Mechanical Engineering,Jiangnan University,Wuxi,Jiangsu 214122,China)
出处
《排灌机械工程学报》
北大核心
2025年第12期1245-1253,共9页
Journal of Drainage and Irrigation Machinery Engineering
基金
南京市交通运输科技项目
镇江市科技计划项目(CS2024002)。
关键词
锂渣
水泥土
无侧限抗压强度
抗剪强度
微观机理
lithium slag
cement-soil
unconfined compression strength
shear strength
microscopic mechanism
