Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteria

The objective of the present study is to develop a biotechnological tool for a new application of silty sand soil as stabilized materials in linear works replacing chemical stabilizer (e.g. cement and lime) by natural cement, formed by precipitated calcium carbonate generated by microorganisms of th...

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Autores: Garzón Garzón, Eduardo, Morales, Rafael, Romero, Esperanza, Sánchez-Soto, Pedro José
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2020
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/221995
Acceso en línea:http://hdl.handle.net/10261/221995
Access Level:acceso abierto
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spelling Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteriaGarzón Garzón, EduardoMorales, RafaelRomero, EsperanzaSánchez-Soto, Pedro JoséThe objective of the present study is to develop a biotechnological tool for a new application of silty sand soil as stabilized materials in linear works replacing chemical stabilizer (e.g. cement and lime) by natural cement, formed by precipitated calcium carbonate generated by microorganisms of the Sporosarcina family. For this purpose, it is conducted a chemical and mineralogical characterization and an examination of physical and geotechnical properties, being very important from the engineering standpoint. The results of different tests are presented here. The data show that the effects of bacteria are reducing the soil specific surface and increasing its plasticity. The reason for this result could be the addition of a plastic component to the natural soil, or the result of the more aggregated structure promoted during the treatment. The pore size distribution of the soil changes in an approximate range 3 - 30 μm, where the pore mode tends to disappear. The change in the pore density function is reflected in the mechanical behaviour of the treated soil, which presents typical features of a less dense soil with respect to the natural untreated one. The friction angle of the treated soil is slightly higher, and its compressibility is consistently lower than that of the natural soil. As the bacteria do not seem to produce any cementation effect on the soil skeleton, collapse upon wetting does not seem to be significantly affected by the treatment. On the contrary, comparison of collapse data shows that occurrence and amount of collapse are ruled by the as-compacted dry density. The tests performed seem to suggest that the microbiological technique may be effective to improve the mechanical characteristics of the compacted soil. For that, it is necessary to provide more energy in compacting the treated soil that it will be stabilized, so as to achieve a high initial dry density. From this viewpoint, it seems that higher compaction effort is even more effective than increasing the amount of bacteria introduced to stabilize the soil.Peer reviewedEDP SciencesConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202020202020info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/221995reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttps://doi.org/10.1051/e3sconf/202019505002Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2219952026-05-22T06:33:51Z
dc.title.none.fl_str_mv Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteria
title Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteria
spellingShingle Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteria
Garzón Garzón, Eduardo
title_short Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteria
title_full Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteria
title_fullStr Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteria
title_full_unstemmed Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteria
title_sort Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteria
dc.creator.none.fl_str_mv Garzón Garzón, Eduardo
Morales, Rafael
Romero, Esperanza
Sánchez-Soto, Pedro José
author Garzón Garzón, Eduardo
author_facet Garzón Garzón, Eduardo
Morales, Rafael
Romero, Esperanza
Sánchez-Soto, Pedro José
author_role author
author2 Morales, Rafael
Romero, Esperanza
Sánchez-Soto, Pedro José
author2_role author
author
author
dc.contributor.none.fl_str_mv Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
description The objective of the present study is to develop a biotechnological tool for a new application of silty sand soil as stabilized materials in linear works replacing chemical stabilizer (e.g. cement and lime) by natural cement, formed by precipitated calcium carbonate generated by microorganisms of the Sporosarcina family. For this purpose, it is conducted a chemical and mineralogical characterization and an examination of physical and geotechnical properties, being very important from the engineering standpoint. The results of different tests are presented here. The data show that the effects of bacteria are reducing the soil specific surface and increasing its plasticity. The reason for this result could be the addition of a plastic component to the natural soil, or the result of the more aggregated structure promoted during the treatment. The pore size distribution of the soil changes in an approximate range 3 - 30 μm, where the pore mode tends to disappear. The change in the pore density function is reflected in the mechanical behaviour of the treated soil, which presents typical features of a less dense soil with respect to the natural untreated one. The friction angle of the treated soil is slightly higher, and its compressibility is consistently lower than that of the natural soil. As the bacteria do not seem to produce any cementation effect on the soil skeleton, collapse upon wetting does not seem to be significantly affected by the treatment. On the contrary, comparison of collapse data shows that occurrence and amount of collapse are ruled by the as-compacted dry density. The tests performed seem to suggest that the microbiological technique may be effective to improve the mechanical characteristics of the compacted soil. For that, it is necessary to provide more energy in compacting the treated soil that it will be stabilized, so as to achieve a high initial dry density. From this viewpoint, it seems that higher compaction effort is even more effective than increasing the amount of bacteria introduced to stabilize the soil.
publishDate 2020
dc.date.none.fl_str_mv 2020
2020
2020
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/221995
url http://hdl.handle.net/10261/221995
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv https://doi.org/10.1051/e3sconf/202019505002
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv EDP Sciences
publisher.none.fl_str_mv EDP Sciences
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
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