Desempenho de concretos com baixo consumo de ligante

Detalhes bibliográficos
Autor(a) principal: Cândido, Taíssa Guedes
Data de Publicação: 2018
Tipo de documento: Dissertação
Idioma: por
Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/15324
Resumo: The concern of the construction industry with environmental issues has stimulated research aiming at the reduction of cement consumption in concrete. This is because cement industry is responsible for more than 5% of CO2 emissions, which are responsible for the increase in greenhouse effect. Research on that matter already testify the possibility of dosing concrete with lower binder levels, maintaining or even improving its mechanical performance. However, there are still no defined mix design methods for these materials that facilitate application in everyday life. Furthermore, there are few studies on durability assessment of these concretes, mainly as to their performance against the action of chlorides. Within this context, this paper presents a concrete mix design method with lower binder contents and evaluates its mechanical performance and durability. Using the principle of aggregate packing and optimization to control paste volume, concretes were elaborated with cement consumption of approximately 280 kg/m³ and 320 kg/m³. These concretes achieved compressive strength above 60 MPa at 28 days. The results indicate that concrete with lower binder consumption has lower content of voids and pores of smaller diameters, offering very high resistance to the penetration of chlorides. On the other hand, conventional concrete with cement consumption of 350 kg/m³ obtained low resistance to the penetration of these aggressive agents. To evaluate the performance against the action of chlorides in concrete with even lower cement consumption, a unidirectional chloride diffusion test was carried out in dosed and molded concretes in the Microstructure Laboratory of the University of São Paulo. The cement consumption of these concretes varied from 140 kg/m³ to 280 kg/m³. For lower cement content, due to very high amounts of incorporated filers it was necessary to use a higher water-cement ratio, which may have caused an increase in porosity and loss of performance as the resistance to chloride penetration. Overall, it is found that it is possible to reduce the amount of binder in the concretes and still improve its mechanical and durability performance. In order to achieve this, it is necessary to use new mix design methods that seek the maximum aggregate packaging and the paste optimization.
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spelling Desempenho de concretos com baixo consumo de liganteSustentabilidadeBaixo consumo de cimentoDurabilidadeCloretosSustainabilityLow cement consumptionDurabilityChloridesConcretoCimento - Redução do consumoConstrução civilCNPQ::ENGENHARIAS::ENGENHARIA CIVILThe concern of the construction industry with environmental issues has stimulated research aiming at the reduction of cement consumption in concrete. This is because cement industry is responsible for more than 5% of CO2 emissions, which are responsible for the increase in greenhouse effect. Research on that matter already testify the possibility of dosing concrete with lower binder levels, maintaining or even improving its mechanical performance. However, there are still no defined mix design methods for these materials that facilitate application in everyday life. Furthermore, there are few studies on durability assessment of these concretes, mainly as to their performance against the action of chlorides. Within this context, this paper presents a concrete mix design method with lower binder contents and evaluates its mechanical performance and durability. Using the principle of aggregate packing and optimization to control paste volume, concretes were elaborated with cement consumption of approximately 280 kg/m³ and 320 kg/m³. These concretes achieved compressive strength above 60 MPa at 28 days. The results indicate that concrete with lower binder consumption has lower content of voids and pores of smaller diameters, offering very high resistance to the penetration of chlorides. On the other hand, conventional concrete with cement consumption of 350 kg/m³ obtained low resistance to the penetration of these aggressive agents. To evaluate the performance against the action of chlorides in concrete with even lower cement consumption, a unidirectional chloride diffusion test was carried out in dosed and molded concretes in the Microstructure Laboratory of the University of São Paulo. The cement consumption of these concretes varied from 140 kg/m³ to 280 kg/m³. For lower cement content, due to very high amounts of incorporated filers it was necessary to use a higher water-cement ratio, which may have caused an increase in porosity and loss of performance as the resistance to chloride penetration. Overall, it is found that it is possible to reduce the amount of binder in the concretes and still improve its mechanical and durability performance. In order to achieve this, it is necessary to use new mix design methods that seek the maximum aggregate packaging and the paste optimization.Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPqA preocupação do setor da construção civil com os problemas ambientais vem impulsionando pesquisas voltadas à redução do consumo de cimento no concreto. Isto porque a indústria do cimento é responsável por mais de 5% das emissões de CO2, responsável pelo aumento do efeito estufa. Já existem trabalhos que comprovam a possibilidade de dosar concretos com menores teores de ligante mantendo ou até mesmo melhorando o seu desempenho mecânico. Entretanto, ainda não há metodologias de dosagens para esses materiais definidas, que facilitem a aplicação no cotidiano. Também há poucos estudos quanto à avaliação da durabilidade destes concretos, principalmente, quanto ao seu desempenho frente à ação dos cloretos. Diante deste contexto, esse trabalho apresenta uma metodologia de dosagem de concretos com menores teores de aglomerantes, e avalia o seu desempenho mecânico e de durabilidade. Utilizando conceitos de empacotamento e otimização da pasta, foram elaborados concretos com consumo de cimento em torno de 280 kg/m³ e 320 kg/m³. Esses concretos alcançaram resistência à compressão acima de 60 MPa aos 28 dias. Os resultados indicam que o concreto com menor consumo de ligante apresenta menor teor de vazios e poros de menores diâmetros, oferecendo altíssima resistência à penetração de cloretos. Já o concreto convencional, com consumo de cimento de 350 kg/m³ obteve baixa resistência à penetração desses agentes agressivos. Visando avaliar o desemprenho frente à ação dos cloretos em concretos com consumo de cimento ainda menores, foi realizado o ensaio de difusão unidirecional de cloretos em concretos dosados e moldados no Laboratório de Microestrutura da Universidade de São Paulo. O consumo de cimento desses concretos variou de 140 kg/m³ a 280 kg/m³. Para os teores mais baixos de cimento, devido às altíssimas quantidades de filers incorporadas, houve necessidade de utilizar um fator água/cimento mais elevado, que pode ter ocasionado um aumento da porosidade e perda de desempenho quanto a resistência à penetração de cloretos. No geral, conclui-se que é possível reduzir a quantidade de ligante nos concretos e ainda melhorar o seu desempenho mecânico e de durabilidade. Para isso, é necessário usar novas metodologias de dosagens, que busquem ao máximo empacotamento dos agregados, e otimização da pasta.Universidade Federal da ParaíbaBrasilEngenharia Cívil e AmbientalPrograma de Pós-Graduação em Engenharia Civil e AmbientalUFPBMeira, Gibson Rochahttp://lattes.cnpq.br/4589258287572417Cândido, Taíssa Guedes2019-08-21T11:56:47Z2019-02-212019-08-21T11:56:47Z2018-03-27info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesishttps://repositorio.ufpb.br/jspui/handle/123456789/15324porAttribution-NoDerivs 3.0 Brazilhttp://creativecommons.org/licenses/by-nd/3.0/br/info:eu-repo/semantics/openAccessreponame:Biblioteca Digital de Teses e Dissertações da UFPBinstname:Universidade Federal da Paraíba (UFPB)instacron:UFPB2019-08-21T11:56:47Zoai:repositorio.ufpb.br:123456789/15324Biblioteca Digital de Teses e Dissertaçõeshttps://repositorio.ufpb.br/PUBhttp://tede.biblioteca.ufpb.br:8080/oai/requestdiretoria@ufpb.br|| diretoria@ufpb.bropendoar:2019-08-21T11:56:47Biblioteca Digital de Teses e Dissertações da UFPB - Universidade Federal da Paraíba (UFPB)false
dc.title.none.fl_str_mv Desempenho de concretos com baixo consumo de ligante
title Desempenho de concretos com baixo consumo de ligante
spellingShingle Desempenho de concretos com baixo consumo de ligante
Cândido, Taíssa Guedes
Sustentabilidade
Baixo consumo de cimento
Durabilidade
Cloretos
Sustainability
Low cement consumption
Durability
Chlorides
Concreto
Cimento - Redução do consumo
Construção civil
CNPQ::ENGENHARIAS::ENGENHARIA CIVIL
title_short Desempenho de concretos com baixo consumo de ligante
title_full Desempenho de concretos com baixo consumo de ligante
title_fullStr Desempenho de concretos com baixo consumo de ligante
title_full_unstemmed Desempenho de concretos com baixo consumo de ligante
title_sort Desempenho de concretos com baixo consumo de ligante
author Cândido, Taíssa Guedes
author_facet Cândido, Taíssa Guedes
author_role author
dc.contributor.none.fl_str_mv Meira, Gibson Rocha
http://lattes.cnpq.br/4589258287572417
dc.contributor.author.fl_str_mv Cândido, Taíssa Guedes
dc.subject.por.fl_str_mv Sustentabilidade
Baixo consumo de cimento
Durabilidade
Cloretos
Sustainability
Low cement consumption
Durability
Chlorides
Concreto
Cimento - Redução do consumo
Construção civil
CNPQ::ENGENHARIAS::ENGENHARIA CIVIL
topic Sustentabilidade
Baixo consumo de cimento
Durabilidade
Cloretos
Sustainability
Low cement consumption
Durability
Chlorides
Concreto
Cimento - Redução do consumo
Construção civil
CNPQ::ENGENHARIAS::ENGENHARIA CIVIL
description The concern of the construction industry with environmental issues has stimulated research aiming at the reduction of cement consumption in concrete. This is because cement industry is responsible for more than 5% of CO2 emissions, which are responsible for the increase in greenhouse effect. Research on that matter already testify the possibility of dosing concrete with lower binder levels, maintaining or even improving its mechanical performance. However, there are still no defined mix design methods for these materials that facilitate application in everyday life. Furthermore, there are few studies on durability assessment of these concretes, mainly as to their performance against the action of chlorides. Within this context, this paper presents a concrete mix design method with lower binder contents and evaluates its mechanical performance and durability. Using the principle of aggregate packing and optimization to control paste volume, concretes were elaborated with cement consumption of approximately 280 kg/m³ and 320 kg/m³. These concretes achieved compressive strength above 60 MPa at 28 days. The results indicate that concrete with lower binder consumption has lower content of voids and pores of smaller diameters, offering very high resistance to the penetration of chlorides. On the other hand, conventional concrete with cement consumption of 350 kg/m³ obtained low resistance to the penetration of these aggressive agents. To evaluate the performance against the action of chlorides in concrete with even lower cement consumption, a unidirectional chloride diffusion test was carried out in dosed and molded concretes in the Microstructure Laboratory of the University of São Paulo. The cement consumption of these concretes varied from 140 kg/m³ to 280 kg/m³. For lower cement content, due to very high amounts of incorporated filers it was necessary to use a higher water-cement ratio, which may have caused an increase in porosity and loss of performance as the resistance to chloride penetration. Overall, it is found that it is possible to reduce the amount of binder in the concretes and still improve its mechanical and durability performance. In order to achieve this, it is necessary to use new mix design methods that seek the maximum aggregate packaging and the paste optimization.
publishDate 2018
dc.date.none.fl_str_mv 2018-03-27
2019-08-21T11:56:47Z
2019-02-21
2019-08-21T11:56:47Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv https://repositorio.ufpb.br/jspui/handle/123456789/15324
url https://repositorio.ufpb.br/jspui/handle/123456789/15324
dc.language.iso.fl_str_mv por
language por
dc.rights.driver.fl_str_mv Attribution-NoDerivs 3.0 Brazil
http://creativecommons.org/licenses/by-nd/3.0/br/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv Attribution-NoDerivs 3.0 Brazil
http://creativecommons.org/licenses/by-nd/3.0/br/
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Universidade Federal da Paraíba
Brasil
Engenharia Cívil e Ambiental
Programa de Pós-Graduação em Engenharia Civil e Ambiental
UFPB
publisher.none.fl_str_mv Universidade Federal da Paraíba
Brasil
Engenharia Cívil e Ambiental
Programa de Pós-Graduação em Engenharia Civil e Ambiental
UFPB
dc.source.none.fl_str_mv reponame:Biblioteca Digital de Teses e Dissertações da UFPB
instname:Universidade Federal da Paraíba (UFPB)
instacron:UFPB
instname_str Universidade Federal da Paraíba (UFPB)
instacron_str UFPB
institution UFPB
reponame_str Biblioteca Digital de Teses e Dissertações da UFPB
collection Biblioteca Digital de Teses e Dissertações da UFPB
repository.name.fl_str_mv Biblioteca Digital de Teses e Dissertações da UFPB - Universidade Federal da Paraíba (UFPB)
repository.mail.fl_str_mv diretoria@ufpb.br|| diretoria@ufpb.br
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