The importance of the microstructure on hydro-mechanical behaviour of compacted granular bentonite
Granular bentonite (GB) with extended grain size distribution, a candidate material to construct engineered barriers, has low water permeability, high swelling potential and self-sealing capacity and is desirable in portability and workability. However, few systematic data combining microstructural...
| Autores: | , , , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/403733 |
| Acceso en línea: | https://hdl.handle.net/2117/403733 https://dx.doi.org/10.1016/j.clay.2023.107177 |
| Access Level: | acceso abierto |
| Palabra clave: | Bentonite Fluid mechanics Granular bentonite Microstructure Hydro-mechanical behaviour Bentonita Mecànica de fluids Àrees temàtiques de la UPC::Edificació::Materials de construcció Àrees temàtiques de la UPC::Enginyeria civil::Materials i estructures |
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The importance of the microstructure on hydro-mechanical behaviour of compacted granular bentoniteZeng, HaoGonzález Blanco, Laura|||0000-0003-3800-3007Romero Morales, Enrique Edgar|||0000-0002-4105-8941Fraccica, AlessandroBentoniteFluid mechanicsGranular bentoniteMicrostructureHydro-mechanical behaviourBentonitaMecànica de fluidsÀrees temàtiques de la UPC::Edificació::Materials de construccióÀrees temàtiques de la UPC::Enginyeria civil::Materials i estructuresGranular bentonite (GB) with extended grain size distribution, a candidate material to construct engineered barriers, has low water permeability, high swelling potential and self-sealing capacity and is desirable in portability and workability. However, few systematic data combining microstructural descriptions and hydro-mechanical (HM) behavioural features are available. The present work investigates the HM performance of Wyoming (MX80)-type GB samples compacted at different initial water contents and at a fixed dry density of 1550 kg/m3. The samples' microstructure and its evolution along stress paths were studied using X-ray micro-computed tomography and mercury intrusion porosimetry. The results highlighted that the compacted GB presented local density heterogeneity and a multi-porosity network. Compaction at low initial water content increased the proportion of macropores and contributed to the enhancement of the compressibility and collapse on wetting under high stresses. During isochoric saturation, two stages of swelling development were identified. First, the flooding of macropores and matric suction reduction was related to the initial increase in swelling pressure. The secondary swelling was due to the water absorption of clay sheets in micropores and the expansion of micropores within granules and aggregates, during which the density of pore water increased. A decrease in the compaction water content can result in a higher pore water density after isochoric saturation and a lower water permeability. Finally, the water retention behaviour of the compacted sample within drying/wetting cycles was less sensitive to the initial pore size distribution. The current outcomes underline the critical role of the microstructure on the HM behaviour of compacted GB.This project has received funding from the European Union's Horizon 2020 research and innovation programme ‘European Joint Programme on Radioactive Waste Management’ EURAD (2019-2024) WP GAS ‘Mechanistic understanding of gas transport in clay materials’ under grant agreement No. 847593. The authors acknowledge the support of NAGRA (National Cooperative for the Disposal of Radioactive Waste) through the project ‘Scientific work related to barrier integrity’ Ref 18722 (2019-2024). The first author has received funding from the China Scholarship Council (CSCPeer Reviewed20232023-12-0120242024-03-05journal articlehttp://purl.org/coar/resource_type/c_6501VoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/2117/403733https://dx.doi.org/10.1016/j.clay.2023.107177reponame:UPCommons. Portal del coneixement obert de la UPCinstname:Universitat Politècnica de Catalunya (UPC)InglésengEuropean Commission http://doi.org/10.13039/100010661 Horizon 2020 Framework Programme 847593 European Joint Programme on Radioactive Waste Managementopen accesshttp://purl.org/coar/access_right/c_abf2Attribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/openAccessoai:upcommons.upc.edu:2117/4037332026-05-27T15:37:01Z |
| dc.title.none.fl_str_mv |
The importance of the microstructure on hydro-mechanical behaviour of compacted granular bentonite |
| title |
The importance of the microstructure on hydro-mechanical behaviour of compacted granular bentonite |
| spellingShingle |
The importance of the microstructure on hydro-mechanical behaviour of compacted granular bentonite Zeng, Hao Bentonite Fluid mechanics Granular bentonite Microstructure Hydro-mechanical behaviour Bentonita Mecànica de fluids Àrees temàtiques de la UPC::Edificació::Materials de construcció Àrees temàtiques de la UPC::Enginyeria civil::Materials i estructures |
| title_short |
The importance of the microstructure on hydro-mechanical behaviour of compacted granular bentonite |
| title_full |
The importance of the microstructure on hydro-mechanical behaviour of compacted granular bentonite |
| title_fullStr |
The importance of the microstructure on hydro-mechanical behaviour of compacted granular bentonite |
| title_full_unstemmed |
The importance of the microstructure on hydro-mechanical behaviour of compacted granular bentonite |
| title_sort |
The importance of the microstructure on hydro-mechanical behaviour of compacted granular bentonite |
| dc.creator.none.fl_str_mv |
Zeng, Hao González Blanco, Laura|||0000-0003-3800-3007 Romero Morales, Enrique Edgar|||0000-0002-4105-8941 Fraccica, Alessandro |
| author |
Zeng, Hao |
| author_facet |
Zeng, Hao González Blanco, Laura|||0000-0003-3800-3007 Romero Morales, Enrique Edgar|||0000-0002-4105-8941 Fraccica, Alessandro |
| author_role |
author |
| author2 |
González Blanco, Laura|||0000-0003-3800-3007 Romero Morales, Enrique Edgar|||0000-0002-4105-8941 Fraccica, Alessandro |
| author2_role |
author author author |
| dc.subject.none.fl_str_mv |
Bentonite Fluid mechanics Granular bentonite Microstructure Hydro-mechanical behaviour Bentonita Mecànica de fluids Àrees temàtiques de la UPC::Edificació::Materials de construcció Àrees temàtiques de la UPC::Enginyeria civil::Materials i estructures |
| topic |
Bentonite Fluid mechanics Granular bentonite Microstructure Hydro-mechanical behaviour Bentonita Mecànica de fluids Àrees temàtiques de la UPC::Edificació::Materials de construcció Àrees temàtiques de la UPC::Enginyeria civil::Materials i estructures |
| description |
Granular bentonite (GB) with extended grain size distribution, a candidate material to construct engineered barriers, has low water permeability, high swelling potential and self-sealing capacity and is desirable in portability and workability. However, few systematic data combining microstructural descriptions and hydro-mechanical (HM) behavioural features are available. The present work investigates the HM performance of Wyoming (MX80)-type GB samples compacted at different initial water contents and at a fixed dry density of 1550 kg/m3. The samples' microstructure and its evolution along stress paths were studied using X-ray micro-computed tomography and mercury intrusion porosimetry. The results highlighted that the compacted GB presented local density heterogeneity and a multi-porosity network. Compaction at low initial water content increased the proportion of macropores and contributed to the enhancement of the compressibility and collapse on wetting under high stresses. During isochoric saturation, two stages of swelling development were identified. First, the flooding of macropores and matric suction reduction was related to the initial increase in swelling pressure. The secondary swelling was due to the water absorption of clay sheets in micropores and the expansion of micropores within granules and aggregates, during which the density of pore water increased. A decrease in the compaction water content can result in a higher pore water density after isochoric saturation and a lower water permeability. Finally, the water retention behaviour of the compacted sample within drying/wetting cycles was less sensitive to the initial pore size distribution. The current outcomes underline the critical role of the microstructure on the HM behaviour of compacted GB. |
| publishDate |
2023 |
| dc.date.none.fl_str_mv |
2023 2023-12-01 2024 2024-03-05 |
| dc.type.none.fl_str_mv |
journal article http://purl.org/coar/resource_type/c_6501 VoR http://purl.org/coar/version/c_970fb48d4fbd8a85 |
| dc.type.openaire.fl_str_mv |
info:eu-repo/semantics/article |
| format |
article |
| dc.identifier.none.fl_str_mv |
https://hdl.handle.net/2117/403733 https://dx.doi.org/10.1016/j.clay.2023.107177 |
| url |
https://hdl.handle.net/2117/403733 https://dx.doi.org/10.1016/j.clay.2023.107177 |
| dc.language.none.fl_str_mv |
Inglés eng |
| language_invalid_str_mv |
Inglés |
| language |
eng |
| dc.relation.none.fl_str_mv |
European Commission http://doi.org/10.13039/100010661 Horizon 2020 Framework Programme 847593 European Joint Programme on Radioactive Waste Management |
| dc.rights.none.fl_str_mv |
open access http://purl.org/coar/access_right/c_abf2 Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ |
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info:eu-repo/semantics/openAccess |
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open access http://purl.org/coar/access_right/c_abf2 Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ |
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openAccess |
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application/pdf |
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reponame:UPCommons. Portal del coneixement obert de la UPC instname:Universitat Politècnica de Catalunya (UPC) |
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UPCommons. Portal del coneixement obert de la UPC |
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