Abstract：To reduce carbon emissions and costs in the production of lightweight foam soils，a serpentine-based carbon sequestration lightweight soil(S-LS) technology that utilizes serpentine tailings，magnesium oxide，and muck as solidifying agents，with carbon dioxide as foaming gas was proposed. The effects of serpentine content，water-solid ratio and wet density on the physical and mechanical properties of S-LS were investigated through laboratory tests. Additionally，the strength formation mechanism and microscopic characteristics of S-LS were analyzed. The results indicate that the CO2 foam can promote the self-carbonation，and the addition of serpentine tailings effectively can improve the workability of slurry. As serpentine content and water-solid ratio increase，and wet density decreases，the flow value of S-LS increases while unconfined compressive strength decreases. In this study，the optimal mix design of S-LS was identified as：serpentine content of 30%，water-solid ratio of 0.55，and wet density of 800 kg/m3. Corresponding to 28 days，the unconfined compressive strength reaches 1.34 MPa，which follows the strength requirements for most foam lightweight soil filling applications. The proposed S-LS technology enhances carbon sequestration and improves solid waste utilization，showing strong potential for engineering application.
[1] 白 玫. 中国水泥工业碳达峰、碳中和实现路径研究[J]. 价格理论与实践，2021，(4)：4–11.(BAI Mei. Research on the path of achieving carbon peak and carbon neutrality in China?s cement industry[J]. Price：Theory and Practice，2021，(4)：4–11.(in Chinese))
[2] YANG S，WANG X，HU Z，et al. Recent advances in sustainable lightweight foamed concrete incorporating recycled waste and byproducts：A review[J]. Construction and Building Materials，2023，403：133083.
[3] 张军辉，陈莎莎，顾 凡，等. 工业废弃料在路基改良中的应用综述[J]. 中国公路学报，2023，36(10)：1–16.(ZHANG Junhui，CHEN Shasha，GU Fan，et al. Industrial waste materials utilized in subgrade modification：A review[J]. China Journal of Highway and Transport，2023，36(10)：1–16.(in Chinese))
[4] HARRISON J，FCPA B S B E. New cements based on the addition of reactive magnesia to Portland cement with or without added pozzolan[C]// Proceedings of the CIA Conference：Concrete in the Third Millenium，CIA. Brisbane，Australia：[s. n.]，2003：24–35.
[5] VANDEPERRE L J，LISKA M，AL-TABBAA A. Hydration and mechanical properties of magnesia，pulverized fuel ash，and portland cement blends[J]. Journal of Materials in Civil Engineering，2008，20(5)：375–383.
[6] LISKA M，AL-TABBAA A. Performance of magnesia cements in pressed masonry units with natural aggregates：production parameters optimisation[J]. Construction and Building Materials，2008，22(8)： 1 789–1 797.
[7] YI Y L，LISKA M，UNLUER C，et al. Carbonating magnesia for soil stabilization[J]. Canadian Geotechnical Journal，2013，50(8)：899–905.
[8] 刘松玉，蔡光华，杜广印，等. 活性氧化镁碳化搅拌桩模型试验研究[J]. 岩土工程学报，2017，39(增2)：136–139.(LIU Songyu，CAI Guanghua，DU Guangyin，et al. Model tests on carbonated reactive MgO mixing piles[J]. Chinese Journal of Geotechnical Engineering，2017，39(Supp.2)：136–139.(in Chinese))
[9] 刘松玉，王 亮，刘宜昭，等. 碳化复合桩(MCP)原理与应用试验研究[J]. 岩土工程学报，2024，46(7)：1 359–1 367.(LIU Songyu，WANG Liang，LIU Yizhao，et al. Experimental study on mechanisms and applications of MgO-carbonated composite pile[J]. Chinese Journal of Geotechnical Engineering，2024，46(7)：1 359–1 367.(in Chinese))
[10] 易耀林，马丁•利什卡，阿尔比•阿勒–塔瓦，等. 一种用于土体固化的绿色低碳固化剂[P]. 中国：CN201010604325.2，2013–01–30.(YI Yaolin，MARTIN Liska，ABIR Al-Tabbaa，et al. A green low-carbon curing agent for soil curing[P]. China：CN201010604325.2，2013–01–30.(in Chinese))
[11] 易耀林，马丁•利什卡，阿尔比•阿勒–塔瓦，等. 一种土壤的碳化固化方法及其装置[P]. 中国：CN201010604013.1，2012–09–19. (YI Yaolin，MARTIN Liska，ABIR Al-Tabbaa，et al. A method of carbonation and solidification of soil and its apparatus[P]. China：CN201010604013.1，2012–09–19.(in Chinese))
[12] 刘松玉，蔡光华，易耀林，等. 一种用于地基加固的处理系统及碳化成桩方法[P]. 中国：CN201410203978.8，2015–10–28.(LIU Songyu，CAI Guanghua，YI Yaolin，et al. A treatment system and a carbonation pile forming method for foundation reinforcement[P]. China：CN201410203978.8，2015–10–28.(in Chinese))
[13] 刘松玉，蔡光华，王 亮，等. 一种碳化搅拌桩–透气管桩复合地基及其施工方法[P]. 中国：CN201710225231.6，2018–07–31. (LIU Songyu，CAI Guanghua，WANG Liang，et al. A kind of carbonation mixing pile-ventilation pipe pile composite foundation and its construction method[P]. China：CN201710225231.6，2018–07–31.(in Chinese))
[14] 蔡光华，刘松玉. 一种碳化搅拌桩–透气管桩复合地基的施工装置[P]. 中国：CN201710224418.4，2019–01–29.(CAI Guanghua，LIU Songyu. A construction device for carbonation mixing pile-ventilation pipe pile composite foundation[P]. China：CN201710224418.4，2019–01–29.(in Chinese))
[15] CAI G H，DU Y J，LIU S Y，et al. Physical properties，electrical resistivity，and strength characteristics of carbonated silty soil admixed with reactive magnesia[J]. Canadian Geotechnical Journal，2015，52(11)：1 699–1 713.
[16] CAI G H，LIU S Y. Compaction and mechanical characteristics and stabilization mechanism of carbonated reactive MgO-stabilized silt[J]. KSCE Journal of Civil Engineering，2017，21(7)：2 641–2 654.
[17] 刘松玉，曹菁菁，蔡光华. 活性氧化镁碳化固化粉质黏土微观机制[J]. 岩土力学，2018，39(5)：1 543–1 552.(LIU Songyu，CAO Jingjing，CAI Guanghua. Microstructural mechanism of reactive magnesia carbonated and stabilized silty clays[J]. Rock and Soil Mechanics，2018，39(5)：1 543–1 552.(in Chinese))
[18] 刘松玉，蔡光华. 碳化固化软弱土理论与技术[M]. 北京：科学出版社，2021：269–273.(LIU Songyu，CAI Guanghua. Carbonation solidification theory and technology for soft soil[M]. Beijing：Science Press，2021：269–273.(in Chinese))
[19] ZHANG X，LIU S Y，WU K，et al. Experimental investigation into the self-carbonation mechanism of magnesium oxide carbon sequestration foamed concrete[J]. Cement and Concrete Composites，2024，148：105486.
[20] ZHANG X，WU K，YUAN Z Y，et al. Investigations into magnesium oxide carbon sequestration foamed concrete：Mechanical performance，microstructure and environmental benefits[J]. Construction and Building Materials，2024，421：135679.
[21] 刘松玉，袁振扬，张 翔. 一种蛇纹石固碳泡沫轻质土及其制备方法[P]. 中国：CN202310043677.2，2023–11–14.(LIU Songyu，YUAN Zhenyang，ZHANG Xiang. A kind of serpentine carbon sequestration foam lightweight soil and its preparation method[P]. China：CN202310043677.2，2023–11–14.(in Chinese))
[22] 彭祥玉，刘文刚，王本英，等. 蛇纹石综合利用现状与展望[J]. 矿产保护与利用，2019，39(4)：99–103.(PENG Xiangyu，LIU Wengang，WANG Benying，et al. Current situation and prospect of comprehensive utilization of serpentine[J]. Conservation and Utilization of Mineral Resources，2019，39(4)：99–103.(in Chinese))
[23] 陈莹丽，杨喜云，童丽嵘，等. 蛇纹石硫酸浸出液制备超细高纯氢氧化镁[J]. 中南大学学报：自然科学版，2024，55(7)：2 468–2 477. (CHEN Yingli，YANG Xiyun，TONG Lirong，et al. Preparation of superfine and high-purity magnesium hydroxide from solution obtained by sulfuric acid leaching serpentine[J]. Journal of Central South University：Science and Technology，2024，55(7)：2 468–2 477.(in Chinese))
[24] ZHANG Q W，SUGIYAMA K，SAITO F. Enhancement of acid extraction of magnesium and silicon from serpentine by mechanochemical treatment[J]. Hydrometallurgy，1997，45(3)：323–331.
[25] 中华人民共和国行业标准编写组. CJJ/T 177—2012气泡混合轻质土填筑工程技术规程[S]. 北京：中国建筑工业出版社，2012.(The Professional Standards Compilation Group of People?s Republic of China. CJJ/T 177—2012 Technical specification for foamed mixture lightweight soil filling engineering[S]. Beijing：China Architecture and Building Press，2012.(in Chinese))
[26] 中华人民共和国国家标准编写组. GB/T 11969—2020蒸压加气混凝土性能试验方法[S]. 北京：中国标准出版社，2020.(The National Standards Compilation Group of People?s Republic of China. GB/T 11969—2020 Test methods of autoclaved aerated concrete[S]. Beijing：Standards Press of China，2020.(in Chinese))
[27] 中华人民共和国行业标准编写组. CECS 249—2008现浇泡沫轻质土技术规程[S]. 北京：中国计划出版社，2008.(The Professional Standards Compilation Group of People?s Republic of China. CECS 249—2008 Technical specification for cast-in-situ foamed lightweight soil[S]. Beijing：China Planning Press，2008.(in Chinese))
[28] 中华人民共和国行业标准编写组. JTGD 30—2015公路路基设计规范[S]. 北京：人民交通出版社，2015.(The Professional Standards Compilation Group of People?s Republic of China. JTGD 30—2015 Specification for Design of Highway Subgrades[S]. Beijing：China Communications Press，2015.(in Chinese))
[29] 刘松玉，李 晨. 氧化镁活性对碳化固化效果影响研究[J]. 岩土工程学报，2015，37(1)：148–155.(LIU Songyu，LI Chen. Influence of MgO activity on stabilization efficiency of carbonated mixing method[J]. Chinese Journal of Geotechnical Engineering，2015，37(1)：148–155.(in Chinese))
[30] ZHANG S K，WANG Z M，LU L，et al. Preparation and load-deformation characterization of carbon nanotube-reinforced foam concrete[J]. Construction and Building Materials，2020，254： 119294.
[31] WANG Z C，LIU S Y，WU K，et al. Study on the mechanical performance of alkali residue-based light-weighted soil[J]. Construction and Building Materials，2023，384：131353.
[32] LI Z，HUA Y，CHANG Z，et al. Hydration，carbonation and strength development of reactive MgO cement blended with lime(CaO) under different curing conditions[J]. Journal of Building Engineering，2023，76：107082.
2025, Vol. 44 
