Solidified Tailings-Contaminated Sludge as an Anti-Seepage Material for Solid Waste Landfills: Mechanical Characteristics and Microscopic Mechanisms
Abstract
This study utilizes an industrial solid-waste composite consolidant (CSGA) to stabilize mine tailings sludge for the development of impermeable materials in solid waste landfills. The evolution of mechanical properties and micro-reaction mechanisms during sludge consolidation was systematically investigated. Unconfined compressive strength and permeability coefficients under varying consolidant dosages and curing periods were determined through unconfined compressive strength tests and flexible-wall permeability tests. FTIR, BET, and TG–DTG characterization techniques were employed to analyze the chemical functional groups, pore structure, and surface micromorphology of the consolidated sludge. The unconfined compressive strength increased markedly with higher consolidant dosages and longer curing periods, reaching 4.61 MPa at 7 days, while the 14-day strength was 73.43% higher than that at 7 days. After 28 days of curing, the permeability coefficient ranged between 5.01×10-8 and 6.74×10-8 cm/s. Substantial amounts of C–S–H or C–A–S–H gels, calcium hydroxide, and ettringite (AFt) formed in the consolidated sludge, and some Ca(OH)₂ underwent carbonation during the later curing stages to produce CaCO₃ that filled internal pores. The synergistic action of NaOH, calcium lignosulfonate, and urea enhanced the reactivity of active components in the industrial solid waste and sludge, promoting gel formation and microstructural densification. This study provides a scientific basis for the design and construction of impermeable materials for mine-tailings-sludge-based landfills.
Article type: Research article
Cited as:
Mao LJ, Cui WY, Chen M, et al. 2025. Solidified Tailings-Contaminated Sludge as an Anti-Seepage Material for Solid Waste Landfills: Mechanical Characteristics and Microscopic Mechanisms. GeoStorage, 1(2), 171-179.
DOI:
https://doi.org/10.46690/gs.2025.02.06Keywords:
Solid waste landfill, impermeable materials, curing agents, mechanical properties, C-S-H gelReferences
Chen ZZ, You NQ, Chen C, et al. 2021. Properties of dredged sludge solidified with alkali-activated slag-based materials and blended with copper slag as fine aggregates of mortars. Construction and Building Materials, 312: 125459. https://doi.org/10.1016/j.conbuildmat.2021.125459.
Chen ML, Wu DZ, Chen KY, et al. 2024. The influence of flyash-based geopolymer on the mechanical properties of OPC solidified soil. Construction and Building Materials, 432: 136591. https://doi.org/10.1016/j.conbuildmat.2024.136591.
Chetri JK, Reddy KR. 2021. Advancements in Municipal Solid Waste Landfill Cover System: A Review. Journal of the Indian Institute of Science, 101(4): 557–588. https://doi.org/10.1007/s41745-021-00229-1.
Corrêa-Silva M, Miranda T, Rouainia M, et al. 2020. Geomechanical behaviour of a soft soil stabilised with alkali activated blast-furnace slags. Journal of Cleaner Production, 267: 122017. https://doi.org/10.1016/j.jclepro.2020.122017.
Dong WY, Gu WY, Zhan QW, et al. 2022. Study on the Property and Mechanism of Low Content Cement-Industrial Waste Residue Silt Solidification. Science of Advanced Materials, 14(12): 1881–1892. https://doi.org/10.1166/sam.2022.4388.
Dong M,Wen XD, Lang L, et al. 2025. Enhanced early strength and microstructural stability of dredged sludge using CPCS curing agent. Construction and Building Materials, 466: 140219. https://doi.org/10.1016/j.conbuildmat.2025.140219.
Duan WJ, Wang DG, Wang ZM, et al. 2021. A novel synergistic method on potential green and high value-added utilization of blast furnace slag. Journal of Cleaner Production, 329:129804. https://doi.org/10.1016/j.jclepro.2021.129804.
Feng DL, Wang J, Wang YX, et al. 2023. Experimental study on solidification/stabilisation of high-salt sludge by alkali activated GGBS and MSWI bottom ash cementitious materials. Case Studies in Construction Materials, 19: e02417. https://doi.org/10.1016/j.cscm.2023.e02417.
Guo ZG, Jiang T, Zhang J, et al. 2020. Mechanical and durability properties of sustainable self-compacting concrete with recycled concrete aggregate and fly ash, slag and silica fume. Construction and Building Materials, 231: 117115. https://doi.org/10.1016/j.conbuildmat.2019.117115.
Han FH, Zhou Y, Zhang ZQ. 2020. Effect of gypsum on the properties of composite binder containing high-volume slag and iron tailing powder. Construction and Building Materials, 252: 119023. https://doi.org/10.1016/j.conbuildmat.2020.119023.
Hou WJ, Ye F, Yu Y, et al. 2025. Experimental study on the strength characteristics and seawater degradation resistance of sandy silt solidified with alkali-activated slag. Construction and Building Materials, 458: 139610. https://doi.org/10.1016/j.conbuildmat.2024.139610.
Huang L, Geng JG, Chen MY, et al. 2023. Investigation into the Rheological Properties and Microstructure of Silt/Crumb Rubber Compound-Modified Asphalt. Polymers, 15(11):2474. https://doi.org/10.3390/polym15112474.
Liu JJ, Yang CH, Song R, et al. 2025. Advances of Geological Storage Engineering and Technology. GeoStorage, 1(1):1–26. https://doi.org/10.46690/gs.2025.01.01.
Liu MY, Lu HJ, Deng QK, et al. 2022. Shear strength, water permeability and microstructure of modified municipal sludge based on industrial solid waste containing calcium used as landfill cover materials. Waste Management, 145: 20–28. https://doi.org/10.1016/j.wasman.2022.04.031.
Liu Y, Lu HJ, Liu MY, et al. 2022. Microanalytical characterizations, mechanical strength and water resistance performance of solidified dredged sludge with industrial solid waste and architecture residue soil. Case Studies in Construction Materials, 17: e01492. https://doi.org/10.1016/j.cscm.2022.e01492.
Liu P, Mo LW, Zhang Z. 2023. Effects of carbonation degree on the hydration reactivity of steel slag in cement-based materials. Construction and Building Materials, 370: 130653. https://doi.org/10.1016/j.conbuildmat.2023.130653.
Metwally GAM, Elemam WE, Mahdy M, et al. 2025. A comprehensive review of metakaolin-based ultra-high performance geopolymer concrete enhanced with waste material additives. Journal of Building Engineering, 103:112019. https://doi.org/10.1016/j.jobe.2025.112019.
Miraki H, Shariatmadari N, Ghadir P, et al. 2022. Clayey soil stabilization using alkali-activated volcanic ash and slag. Journal of Rock Mechanics and Geotechnical Engineering, 14(2): 576–591. https://doi.org/10.1016/j.jrmge.2021.08.012.
Ramadan M, Habib AO, Hazem MM, et al. 2023. Synergetic effects of hydrothermal treatment on the behavior of toxic sludge-modified geopolymer: Immobilization of cerium and lead, textural characteristics, and mechanical efficiency. Construction and Building Materials, 367: 130249. https://doi.org/10.1016/j.conbuildmat.2022.130249.
Shi XM, Xu HQ, Zhang N, et al. 2023. Study on semi-dynamic leaching and microstructure characteristics of MSWI fly ashsolidified sediment. Journal of Environmental Management, 348: 119405. https://doi.org/10.1016/j.jenvman.2023.119405.
Shu BN, Chen WZ, Yang TY, et al. 2022. Study on laboratory and engineering application of multi source solid waste based soft soil solidification materials. Case Studies in Construction Materials, 17: e01465. https://doi.org/10.1016/j.cscm.2022.e01465.
Song YB, Zhang XP, Xu JX, et al. 2025. Mechanical properties and water resistance of alkali-activated flood control stone incorporating ball-milling treated Yellow River silt. Case Studies in Construction Materials, 22: e04640. https://doi.org/10.1016/j.cscm.2025.e04640.
Sun HQ, Qian JS, Yang YL, et al. 2020. Optimization of gypsum and slag contents in blended cement containing slag. Cement & Concrete Composites, 112: 103674. https://doi.org/10.1016/j.cemconcomp.2020.103674.
Wang L,Yan DY, Xiong Y, et al. 2019. A review of the challenges and application of public-private partnership model in Chinese garbage disposal industry. Journal of Cleaner Production, 230: 219–229. https://doi.org/10.1016/j.jclepro.2019.05.028.
Wang DX, Zhu JY, Wang RH. 2021. Assessment of magnesium potassium phosphate cement for waste sludge solidification: Macro- and micro-analysis. Journal of Cleaner Production, 294: 126365. https://doi.org/10.1016/j.jclepro.2021.126365.
Wu S, Yao XL, Ren CZ, et al. 2020. Recycling phosphogypsum as a sole calcium oxide source in calcium sulfoaluminate cement and its environmental effects. Journal of Environmental Management, 271: 110986. https://doi.org/10.1016/j.jenvman.2020.110986.
Wu MM, Shen WG, Xiong X, et al. 2023. Effects of the phosphogypsum on the hydration and microstructure of alkali activated slag pastes. Construction and Building Materials, 368: 130391. https://doi.org/10.1016/j.conbuildmat.2023.130391.
Xiao Y, Tan YZ, Zhou CL, et al. 2024. Utilisation of silica-rich waste in eco phosphogypsum-based cementitious materials: Strength, microstructure, thermodynamics and CO2 sequestration. Construction and Building Materials, 411: 134469. https://doi.org/10.1016/j.conbuildmat.2023.134469.
Downloads
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2025 GeoStorage
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.