Estudo de ligante geopolimérico obtido a partir de metacaulim e escória granulada de alto forno
The need for alternative materials to replace Portland cement is a contemporary discussion. Those new and alternative materials must have a sustainable character and good durability to supply the demand of the civil construction sector and mitigate the environmental crises caused by the industry, su...
| Autor principal: | MORAES, Mario Henrique Moreira de |
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| Grau: | Dissertação |
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Universidade Federal do Pará
2023
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https://repositorio.ufpa.br/jspui/handle/2011/15713 |
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ir-2011-157132023-06-20T13:18:28Z Estudo de ligante geopolimérico obtido a partir de metacaulim e escória granulada de alto forno Experimental study of geopolymer binder produced with metakaolin and ground granulated blast furnace slag. MORAES, Mario Henrique Moreira de PICANÇO, Marcelo de Souza http://lattes.cnpq.br/4535052395600357 SILVA, Alisson Clay Rios da http://lattes.cnpq.br/7389345867032737 Cimento geopolimérico Resistência mecânica Metacaulim Resíduos industriais Sustentabilidade Geopolymer cement Compressive strength Metakaolin Solid Wastes Sustainability CNPQ::ENGENHARIAS::ENGENHARIA CIVIL ESTRUTURAS E CONSTRUÇÃO CIVIL ENGENHARIA DE CONSTRUÇÃO CIVIL The need for alternative materials to replace Portland cement is a contemporary discussion. Those new and alternative materials must have a sustainable character and good durability to supply the demand of the civil construction sector and mitigate the environmental crises caused by the industry, such as the high emission rate of CO2. In this context, geopolymeric binders appear as materials produced by different solid precursors in contact with an alkaline activator, with zero CO2 emission and mechanical properties and durability compatible or superior to that of Portland cement. Thus, this study aimed to evaluate the geopolymeric binder obtained from the combination of metakaolin (MK) and ground granulated blast furnace slag (GGBFS) with three different molar concentrations of sodium hydroxide (8, 10, and 12 M) for the alkaline activator. Dosages were established from the partial mass substitution of MK by GGBFS, coded as G0 (100% MK 0% EAF), G20 (80% MK 20% EAF), and G40 (60% MK 40% EAF). XRD, XRF, and SEM analyses were conducted for solid precursors. Geopolymer pastes properties were evaluated in the fresh state regarding setting time and in the hardened state based on physical tests, average compressive strength, and fracture morphology. Results showed that the MK and the GGBFS have adequate reactivity and chemical composition for the geopolymer synthesis, with the presence of calcium in the GGBFS actively contributing to the reduction of the setting time and gain of mechanical resistance of the dosages. As for the hardened state, higher levels of water absorption are intrinsically related to a decrease in mechanical strength, with fracture analysis revealing the presence of pores and micropores that favor the propagation of cracks. Statistical analysis found that the interaction between the analyzed factors significantly influenced the properties of the materials, with 85.35% (R2 = 0.8535) of the model being able to explain the variation in compressive strength of geopolymers as a function of the factors used in the regression, limited to the chosen range of variables. The G40M12 formulation showed the highest compressive strength value (38.08 MPa) and the ideal synthesis parameters defined were the rotational frequency at 150 RPM, a partial replacement of MK by GGBFS of 40%, and the NaOH concentration of 12 M. Finally, from the correlation of the evaluated characteristics, the developed geopolymeric binders showed technological potential as alternative and sustainable materials, with properties comparable to those of Portland cement. Muito se discute sobre a necessidade de materiais cimentícios alternativos ao cimento Portland, que possuam caráter sustentável e propriedades tecnológicas adequadas, que supram a demanda do setor de construção civil e mitiguem as crises ambientais ocasionadas pela indústria, como por exemplo, a alta taxa de emissão de CO2. Nesse contexto, surgem os ligantes geopoliméricos, materiais que podem ser sintetizados a partir de diferentes precursores sólidos em contato com um ativador alcalino e com emissão de CO2 próxima a zero, com propriedades mecânicas e de durabilidade compatíveis ou superiores ao do cimento Portland. Dessa forma, o presente estudo se propôs a avaliar o ligante geopolimérico obtido a partir da combinação de metacaulim (MK) e escória granulada de alto forno (EAF), com três diferentes concentrações molares de hidróxido de sódio (8, 10 e 12 molar) para o ativador alcalino. Estabeleceu-se três formulações a partir da substituição parcial em massa de MK por EAF, sendo chamadas de G0 (100% MK 0% EAF), G20 (80% MK 20% EAF) e G40 (60% MK 40% EAF). Os precursores sólidos foram caracterizados via DRX, FRX e MEV, as pastas geopoliméricas foram avaliadas no estado fresco quanto a tempo de pega e massa específica, e no estado endurecido a partir de análises físicas, de resistência média à compressão e morfologia da fratura. Os resultados demonstraram que o MK e a EAF utilizados possuem reatividade e composição química adequadas para a síntese geopolimérica, com a presença de cálcio na EAF contribuindo ativamente para a diminuição do tempo de pega e ganho de resistência mecânica das formulações. Teores mais altos de absorção de água demonstraram-se intrinsecamente relacionados a diminuição de resistência mecânica, com a análise da fratura revelando a presença de poros e microporos que favorecem a propagação de trincas. A análise estatística constatou que a interação entre os fatores analisados influenciou de modo significativo nas propriedades dos materiais estudados, com 85,35% (R2 = 0,8535) do modelo obtido sendo apto a explicar a variação de resistência à compressão dos geopolímeros em função dos fatores utilizados na regressão. A formulação G40M12 apresentou o maior valor de resistência à compressão (38,08 MPa), os parâmetros de síntese ideais definidos foram a velocidade de rotação a 150 RPM, a substituição parcial de MK por EAF de 40% e a concentração de NaOH de 12 M. Por fim, a partir da correlação das características avaliadas, verificou-se que os ligantes geopoliméricos desenvolvidos possuem potencial tecnológico como materiais alternativos e de caráter sustentável, com propriedades comparáveis as do cimento Portland. 2023-06-20T13:14:23Z 2023-06-20T13:14:23Z 2022-12-06 Dissertação MORAES, Mario Henrique Moreira de. Estudo de ligante geopolimérico obtido a partir de metacaulim e escória granulada de alto forno. Orientador: Marcelo de Souza Picanço; Coorientador: Alisson Clay Rios da Silva. 2022. 100 f. Dissertação (Mestrado em Engenharia Civil ) - Universidade Federal do Pará, Instituto de Tecnologia, Belém, 2022. Disponível em:https://repositorio.ufpa.br/jspui/handle/2011/15713. Acesso em:. https://repositorio.ufpa.br/jspui/handle/2011/15713 por Acesso Aberto Attribution-NonCommercial-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nc-nd/3.0/br/ application/pdf Universidade Federal do Pará Brasil Instituto de Tecnologia UFPA Programa de Pós-Graduação em Engenharia Civil 1 CD ROM Disponível na internet via correio eletrônico: bibliotecaitec@ufpa.br |
| institution |
Repositório Institucional - Universidade Federal do Pará |
| collection |
RI-UFPA |
| language |
por |
| topic |
Cimento geopolimérico Resistência mecânica Metacaulim Resíduos industriais Sustentabilidade Geopolymer cement Compressive strength Metakaolin Solid Wastes Sustainability CNPQ::ENGENHARIAS::ENGENHARIA CIVIL ESTRUTURAS E CONSTRUÇÃO CIVIL ENGENHARIA DE CONSTRUÇÃO CIVIL |
| spellingShingle |
Cimento geopolimérico Resistência mecânica Metacaulim Resíduos industriais Sustentabilidade Geopolymer cement Compressive strength Metakaolin Solid Wastes Sustainability CNPQ::ENGENHARIAS::ENGENHARIA CIVIL ESTRUTURAS E CONSTRUÇÃO CIVIL ENGENHARIA DE CONSTRUÇÃO CIVIL MORAES, Mario Henrique Moreira de Estudo de ligante geopolimérico obtido a partir de metacaulim e escória granulada de alto forno |
| topic_facet |
Cimento geopolimérico Resistência mecânica Metacaulim Resíduos industriais Sustentabilidade Geopolymer cement Compressive strength Metakaolin Solid Wastes Sustainability CNPQ::ENGENHARIAS::ENGENHARIA CIVIL ESTRUTURAS E CONSTRUÇÃO CIVIL ENGENHARIA DE CONSTRUÇÃO CIVIL |
| description |
The need for alternative materials to replace Portland cement is a contemporary discussion. Those new and alternative materials must have a sustainable character and good durability to supply the demand of the civil construction sector and mitigate the environmental crises caused by the industry, such as the high emission rate of CO2. In this context, geopolymeric binders appear as materials produced by different solid precursors in contact with an alkaline activator, with zero CO2 emission and mechanical properties and durability compatible or superior to that of Portland cement. Thus, this study aimed to evaluate the geopolymeric binder obtained from the combination of metakaolin (MK) and ground granulated blast furnace slag (GGBFS) with three different molar concentrations of sodium hydroxide (8, 10, and 12 M) for the alkaline activator. Dosages were established from the partial mass substitution of MK by GGBFS, coded as G0 (100% MK 0% EAF), G20 (80% MK 20% EAF), and G40 (60% MK 40% EAF). XRD, XRF, and SEM analyses were conducted for solid
precursors. Geopolymer pastes properties were evaluated in the fresh state regarding setting time and in the hardened state based on physical tests, average compressive strength, and fracture morphology. Results showed that the MK and the GGBFS have adequate reactivity and chemical composition for the geopolymer synthesis, with the presence of calcium in the GGBFS actively contributing to the reduction of the setting time and gain of mechanical resistance of the dosages. As for the hardened state, higher levels of water absorption are intrinsically related to a decrease in mechanical strength, with fracture analysis revealing the presence of pores and micropores that favor the propagation of cracks. Statistical analysis found that the interaction between the analyzed factors significantly influenced the properties of the materials, with 85.35% (R2 = 0.8535) of the model being able to explain the variation in compressive strength of geopolymers as a function of the factors used in the regression, limited to the chosen range of variables. The G40M12 formulation showed the highest compressive strength value (38.08 MPa) and the ideal synthesis parameters defined were the rotational frequency at 150 RPM, a partial replacement of MK by GGBFS of 40%, and the NaOH concentration of 12 M. Finally, from the correlation of the evaluated characteristics, the developed geopolymeric binders showed technological potential as alternative and sustainable materials, with properties comparable to those of Portland cement. |
| author_additional |
PICANÇO, Marcelo de Souza |
| author_additionalStr |
PICANÇO, Marcelo de Souza |
| format |
Dissertação |
| author |
MORAES, Mario Henrique Moreira de |
| title |
Estudo de ligante geopolimérico obtido a partir de metacaulim e escória granulada de alto forno |
| title_short |
Estudo de ligante geopolimérico obtido a partir de metacaulim e escória granulada de alto forno |
| title_full |
Estudo de ligante geopolimérico obtido a partir de metacaulim e escória granulada de alto forno |
| title_fullStr |
Estudo de ligante geopolimérico obtido a partir de metacaulim e escória granulada de alto forno |
| title_full_unstemmed |
Estudo de ligante geopolimérico obtido a partir de metacaulim e escória granulada de alto forno |
| title_sort |
estudo de ligante geopolimérico obtido a partir de metacaulim e escória granulada de alto forno |
| publisher |
Universidade Federal do Pará |
| publishDate |
2023 |
| url |
https://repositorio.ufpa.br/jspui/handle/2011/15713 |
| _version_ |
1787147627446403072 |
| score |
11.755432 |