Mechanical properties and mechanism of co-curing saline soil with coal solid waste

Authors

DONG Chenxi, College of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, China; State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Science, Wuhan 430071, ChinaFollow
WANG Nianqin, College of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, China
LI Jiangshan, State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Science, Wuhan 430071, ChinaFollow
CHEN Xin, State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Science, Wuhan 430071, China
YAN Xusheng, College of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, China
MA Wei, College of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, China

Abstract

Under the research background of resource utilization of solid wastes in the arid and semiarid regions, a new curing material was developed with the coal wastes (such as the coal gangue (CG) and coal metakaolin (CMK)), the carbide slag (CS) that is a waste material readily available in the arid region, and the ordinary Portland cement (OPC). Besides, its mechanical properties and microscopic change mechanism in curing of saline soil in the arid and semi-arid regions were discussed. Based on the laboratory experiment, the unconfined compressive strength (UCS) characteristics of curing saline soil in different ages were studied by replacing 52%, 60%, 68%, 72% and 84% OPC with CG from different mines and CG-CMK-CS, and comparison was made with the saline soil cured with 100% OPC. Then, the characteristic groups were taken for the leaching tests of harmful anions (Cl⁻ and SO₄ ²⁻) and microscopic tests to investigate the strength change mechanism from a microscopic perspective. The results show that the CG-CS-CMK-OPC system has a good ability of binding Cl⁻ and SO₄ ²⁻, with the leaching amount of Cl⁻ and SO₄ ²⁻ equivalent to only half of that cured by 100% OPC. Further, the hydration product tricalcium aluminate could form AFm with Cl⁻ and SO₄ ²⁻ in the saline soil, and thus the intra-agglomerate and inter-agglomerate pores in the system are transformed into intra-granular and inter-granular pores, reducing the hazard caused by salt in saline soil. The results of the 7d UCS test show that Shanxi Yuncheng CG curing system has the best strength, which is related to its high content of active calcium and ferroaluminum, as well as the low content of biomass. Shaanxi Yulin CG takes the second place and Shaanxi Xianyang CG has the worst performance. After replacing 52% OPC for curing saline soil with CG-CMK-CS, the compression strength of some test groups q_u exceeded that of curing saline soil with 100%OPC. Even after the replacement of 84%OPC, CG-CMK-CS-OPC can still meet the strength requirements of cement and fly ash material for highway base. Therefore, CG-CS-CMK-OPC can be used as a green, economic, environmental friendly and low-carbon curing material and promoted in the application of saline soil road subgrade engineering in the arid and semi-arid regions.

Keywords

coal gangue, alkali activation, saline soil, microscopic mechanism, mechanical characteristics, curing material

DOI

10.12363/issn.1001-1986.22.05.0382

Recommended Citation

DONG Chenxi, WANG Nianqin, LI Jiangshan, et al. (2023) "Mechanical properties and mechanism of co-curing saline soil with coal solid waste," Coal Geology & Exploration: Vol. 51: Iss. 3, Article 53.
DOI: 10.12363/issn.1001-1986.22.05.0382
Available at: https://cge.researchcommons.org/journal/vol51/iss3/53

Reference

[1] 邓军. 煤矸石特性分析和综合利用研究[J]. 煤炭技术,2009,28(6):149−150.

DENG Jun. Analysis of gangue characteristics and research on comprehensive utilization of gangue[J]. Coal Technology,2009,28(6):149−150.

[2] 白国良，刘瀚卿，朱可凡，等. 陕北矿区不同矿源煤矸石混凝土抗压强度试验研究[J/OL]. 土木工程学报，2022：1–11 [2022-05-18]. DOI: 10.15951/j.tmgcxb.21121197.

LIU Hanqing，ZHU Kefan，et al. Experimental study on compressive strength of coal gangue concrete from different ore sources in Northern Shaanxi Mining Area[J/OL]. China Civil Engineering Journal，2022：1–11 [2022-05-18]. DOI: 10.15951/j.tmgcxb.21121197.

[3] 杨丰隆. 煤矸石堆积区土壤生态健康风险与毒性效应研究[D]. 太原：山西大学，2020.

YANG Fenglong. Research on the ecological health risk and toxicity effects of soil from coal gangue stacking area[D]. Taiyuan：Shanxi University，2020.

[4] 杨果林,陈子昂,段君义,等. 格宾网加筋煤矸石界面剪切特性及路堤边坡稳定性研究[J]. 煤田地质与勘探,2021,49(6):186−192.

YANG Guolin,CHEN Zi’ang,DUAN Junyi,et al. Interfacial shear behavior of gabion reinforced coal gangue and stability of embankment slope[J]. Coal Geology & Exploration,2021,49(6):186−192.

[5] 茅艳,许波. 利用煤矸石生产建筑材料及其对性能特性的分析[J]. 中国矿业,2004,13(8):48−51.

MAO Yan,XU Bo. Analysis of gangue’s characteristic when using it to produce construction material[J]. China Mining Magazine,2004,13(8):48−51.

[6] 白国良，刘瀚卿，刘辉，等. 煤矸石理化特性及其对混凝土强度的影响[J/OL]. 建筑结构学报，2021：1–12 [2022-05-18]. DOI：10.14006/j.jzjgxb.2021.0735.

BAI Guoliang，LIU Hanqing，LIU Hui，et al. Physicochemical properties of coal gangue and its influence on concrete strength[J/OL]. Journal of Building Structures，2021：1–12 [2022-05-18]. DOI：10.14006/j.jzjgxb.2021.0735.

[7] ZHANG Yuzhuo,WANG Qinghe,ZHOU Mei,et al. Mechanical properties of concrete with coarse spontaneous combustion gangue aggregate (SCGA):Experimental investigation and prediction methodology[J]. Construction and Building Materials,2020,255:119337.

[8] 刘潮,水中和,高旭,等. 碱激发煤矸石–高炉矿渣复合材料性能评价[J]. 硅酸盐通报,2020,39(9):2877−2884.

LIU Chao,SHUI Zhonghe,GAO Xu,et al. Performance evaluation of alkali–activated coal gangue–blast furnace slag composite[J]. Bulletin of the Chinese Ceramic Society,2020,39(9):2877−2884.

[9] 马宏强,易成,陈宏宇,等. 碱激发煤矸石–矿渣胶凝材料的性能和胶结机理[J]. 材料研究学报,2018,32(12):898−904.

MA Hongqiang,YI Cheng,CHEN Hongyu,et al. Property and cementation mechanism of alkali–activated coal gangue–slag cementitious materials[J]. Chinese Journal of Materials Research,2018,32(12):898−904.

[10] 张建俊,姚柏聪,王宝强,等. 离子固化剂固化煤矸石粉作用机理[J]. 煤炭学报,2022,47(6):2446−2454.

ZHANG Jianjun,YAO Baicong,WANG Baoqiang,et al. Mechanism of action of coal gangue powder stabilized by ionic stabilizer[J]. Journal of China Coal Society,2022,47(6):2446−2454.

[11] HUANG Guodong,JI Yongsheng,LI Jun,et al. Improving strength of calcinated coal gangue geopolymer mortars via increasing calcium content[J]. Construction and Building Materials,2018,166:760−768.

[12] 李剑锋. 煤矸石–电石渣地聚物胶凝材料固化软土的试验研究与应用[D]. 广州：广州大学，2021.

LI Jianfeng. Experimental study and application of coal gangue carbide slag geopolymer cementitious material to solidify soft soil[D]. Guangzhou：Guangzhou University，2021.

[13] 王林浩. 煤系偏高岭土复合水泥土工程特性及相关机理研究[D]. 太原：太原理工大学，2018.

WANG Linhao. Engineering properties and mechanism of composite cemented soils with coal–bearing metakaolin[D]. Taiyuan：Taiyuan University of Technology，2018.

[14] 王安辉,潘春宇,黄益平,等. 煤系偏高岭土对煤矸石混凝土性能的影响研究[J]. 混凝土与水泥制品,2021(10):25−28.

WANG Anhui,PAN Chunyu,HUANG Yiping,et al. Effect of coal metakaolin on performance of coal gangue concrete[J]. China Concrete and Cement Products,2021(10):25−28.

[15] 龙林丽,刘英,张旭阳,等. 无人机在矿区表土特征及地质灾害监测中的应用[J]. 煤田地质与勘探,2021,49(6):200−211.

LONG Linli,LIU Ying,ZHANG Xuyang,et al. Application of unmanned aerial vehicle in surface soil characterization and geological disaster monitoring in mining areas[J]. Coal Geology & Exploration,2021,49(6):200−211.

[16] 李敏,于禾苗,杜红普,等. 冻融循环对二灰和改性聚乙烯醇固化盐渍土力学性能的影响[J]. 岩土力学,2022,43(2):489−498.

LI Min,YU Hemiao,DU Hongpu,et al. Mechanical properties of saline soil solidified with the mixture of lime,fly ash and modified polyvinyl alcohol under freeze–thaw cycles[J]. Rock and Soil Mechanics,2022,43(2):489−498.

[17] 曾平江. 冻融作用下水泥改良盐渍土物理力学性质研究[J]. 公路与汽运,2020(4):75−78.

ZENG Pingjiang. Research on physical and mechanical properties of cement–modified saline soil under freeze–thaw cycles[J]. Highways & Automotive Applications,2020(4):75−78.

[18] 杨伟武. 石灰–硅灰改良硫酸盐渍土工程特性试验研究及机理分析[D]. 兰州：兰州理工大学，2021.

YANG Weiwu. The study on engineering characteristics and improvement mechanism of sulfate salty soil modified by lime– silica fume[D]. Lanzhou：Lanzhou University of Technology，2021.

[19] 李宏波,田军仓,边兴. 掺加硅灰和石灰条件下的超盐渍土抗剪特征研究[J]. 广西大学学报(自然科学版),2016,41(4):1145−1152.

LI Hongbo,TIAN Juncang,BIAN Xing. Investigation on shear characteristics of hypersaline soil improved by lime and silica fume[J]. Journal of Guangxi University (Natural Science Edition),2016,41(4):1145−1152.

[20] 王亮,慈军,杨志豪,等. 电石渣–火山灰质胶凝材料固化盐渍土试验研究[J]. 新型建筑材料,2020,47(5):46−49.

WANG Liang,CI Jun,YANG Zhihao,et al. Experimental study on solidified saline soil with calcium carbide slag and volcanic ash cementitious materials[J]. New Building Materials,2020,47(5):46−49.

[21] 刘诚斌,纪洪广,刘娟红,等. 矿渣复合胶凝材料固化滨海盐渍土的试验研究[J]. 建筑材料学报,2015,18(1):82−87.

LIU Chengbin,JI Hongguang,LIU Juanhong,et al. Experimental study on slag composite cementitious material for solidifying coastal saline soil[J]. Journal of Building Materials,2015,18(1):82−87.

[22] 魏丽,柴寿喜. SH固土剂对滨海盐渍土的固化作用评价[J]. 工程地质学报,2018,26(2):407−415.

WEI Li,CHAI Shouxi. Evaluation of solidifying effect of SH agent on inshore saline soils[J]. Journal of Engineering Geology,2018,26(2):407−415.

[23] 中华人民共和国水利部. 土工试验方法标准：GB/T50123—2019[S]. 北京：中国计划出版社，2019.

[24] 王川,刘超,裴文晶,等. 活化煤矸石制备路基充填材料的探讨[J]. 材料科学与工程学报,2022,40(1):97−103.

WANG Chuan,LIU Chao,PEI Wenjing,et al. Discussion on the preparation of roadbed filling material with activated coal gangue[J]. Journal of Materials Science & Engineering,2022,40(1):97−103.

[25] 交通部公路科学研究院. 公路工程无机结合料稳定材料试验规程：JTG E51—2009[S]. 北京：人民交通出版社，2009.

[26] 赵永生. 利用工业废渣配制软土固化剂的原理与方法[D]. 北京：北京航空航天大学，2007.

ZHAO Yongsheng. Principle and method for preparing stabilizing agent for soft soil by industrial wastes[D]. Beijing：Beihang University，2007.

[27] 周恒宇,王修山,胡星星,等. 地聚合物固化淤泥强度增长影响因素及机制分析[J]. 岩土力学,2021,42(8):2089−2098.

ZHOU Hengyu,WANG Xiushan,HU Xingxing,et al. Influencing factors and mechanism analysis of strength development of geopolymer stabilized sludge[J]. Rock and Soil Mechanics,2021,42(8):2089−2098.

[28] SHEAR D L，OLSEN H W，NELSON K R. Effects of desiccation on the hydraulic conductivity versus void ratio relationship for a natural clay[M]. Washington DC：National Academy Press，1992.

[29] 中华人民共和国交通运输部. 公路路面基层施工技术细则：JTG/T F20—2015[S]. 北京：人民交通出版社，2015.

[30] SHI Jinyan,TAN Jinxia,LIU Baoju,et al. Experimental study on full–volume slag alkali–activated mortars:Air–cooled blast furnace slag versus machine−made sand as fine aggregates[J]. Journal of Hazardous Materials,2021,403:123983.

[31] 陈应强,冯华军,陈务江,等. 浙江省典型行业含钙类废物特性调查及水泥资源化综合利用可行性分析[J]. 浙江大学学报(理学版),2013,40(1):76−82.

CHEN Yingqiang,FENG Huajun,CHEN Wujiang,et al. Investigation and cement recycle analysis of calcic solid waste of Zhejiang representative industry[J]. Journal of Zhejiang University (Science Edition),2013,40(1):76−82.

[32] 张俊,张生,李畅游,等. 基于土柱淋滤实验的煤矸石饱和状态下溶质释放过程研究[J]. 煤田地质与勘探,2012,40(5):56−59.

ZHANG Jun,ZHANG Sheng,LI Changyou,et al. Coal gangue saturated solute release process based on the soil column leaching experiments[J]. Coal Geology & Exploration,2012,40(5):56−59.

[33] 时松,刘长武,吴海宽,等. 粉煤灰–电石渣双掺改性高水充填材料物理力学性能研究[J]. 材料导报,2021,35(7):7027−7032.

SHI Song,LIU Changwu,WU Haikuan,et al. Study on physical and mechanical properties of modified high water filling material with fly ash and calcium carbide slag[J]. Materials Reports,2021,35(7):7027−7032.

[34] 程东幸,刘志伟,柯学. 粗颗粒盐渍土溶陷性影响因素研究[J]. 工程地质学报,2013,21(1):109−114.

CHENG Dongxing,LIU Zhiwei,KE Xue. Field and laboratory tests for influential factors on salt resolving slump of coarse particle saline soil[J]. Journal of Engineering Geology,2013,21(1):109−114.

[35] 杨鹏,朱彦鹏,米海珍. 粗颗粒硫酸盐渍土失水盐胀微观机理的试验研究[J]. 兰州理工大学学报,2019,45(5):130−134.

YANG Peng,ZHU Yanpeng,MI Haizhen. Experimental investigation of microscopic mechanism of salt–expansion and dehydration of salty soil soaked by coarse–particle sulphate[J]. Journal of Lanzhou University of Technology,2019,45(5):130−134.

[36] 王中平,彭相,赵亚婷,等. 海水对不同矿物组成的铝酸盐水泥水化的影响[J]. 硅酸盐学报,2020,48(8):1240−1248.

WANG Zhongping,PENG Xiang,ZHAO Yating,et al. Effect of seawater on hydration of calcium aluminate cement with different mineral compositions[J]. Journal of the Chinese Ceramic Society,2020,48(8):1240−1248.

[37] 储洪强,王婷婷,张宇衡,等. 氯盐–硫酸盐共存环境中杂散电流作用下提升砂浆中氯离子结合性能的研究[J]. 材料导报,2021,35(18):18069−18075.

CHU Hongqiang,WANG Tingting,ZHANG Yuheng,et al. Study on improving chloride binding capacity in mortar under stray current in chloride–sulfate coexisting environment[J]. Materials Reports,2021,35(18):18069−18075.

[38] 谷上海,黄敦文,杨翼玮,等. 碱激发偏高岭土–矿渣对氯离子的固化能力及其影响因素[J]. 西安建筑科技大学学报(自然科学版),2022,54(2):191−201.

GU Shanghai,HUANG Dunwen,YANG Yiwei,et al. Chloride binding ability of alkali activated metakaolin/slag blends and its influencing factors[J]. Journal of Xi’an University of Architecture & Technology (Natural Science Edition),2022,54(2):191−201.

[39] HUANG Xiao,XIN Chen,LI Jiangshan,et al. Using hazardous barium slag as a novel admixture for alkali activated slag cement[J]. Cement and Concrete Composites,2022,125:104332.