Estudo da álcali-ativação na produção de tijolos modulares ecológicos
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Data
2022-02-18
Autores
Gonçalves, Lucas Félix da Costa
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Com a crescente demanda da construção civil por novos materiais que preferencialmente minimizem os impactos ambientais e atendam as solicitações técnicas, o tijolo solo-cimento, conhecido comercialmente como tijolo ecológico, surge como alternativa ao tijolo de argila queimada, que gera impacto pelo seu processo de queima e consumo de energia. Ao analisar o tijolo solo-cimento, encontram-se benefícios econômicos, sociais e ambientais em sua produção, porém, ele ainda conta com um componente que possui contribuição para impacto ambiental, que é o cimento. Estudos mostram que há possibilidades de substituição do cimento nesta produção e a técnica com resultados promissores é a álcali-ativação. Visto as possibilidades, o presente trabalho propôs a produção do tijolo modular de solo comprimido e estabilizado a partir da técnica de álcali-ativação, em escala real. Foram estudados 4 variações de matérias-primas e metodologias de produção, envolvendo uma matriz fixa de solo e areia, metacaulim ou escória de alto forno como precursores, ativador simples com solução de NaOH ou composto com adição de cal hidratada, com ou sem cura térmica. A partir das caracterizações mecânicas e físicas dos tijolos foi possível concluir que a produção envolvendo metacaulim como precursor, ativador composto, com cura térmica e a produção com escória de alto forno como precursor, ativador simples, com cura térmica, atenderam todos os requisitos estabelecidos pela norma ABNT NBR 8491:2012 usada de referência. Os tijolos com a escória de alto forno alcançaram os maiores valores de resistência à compressão com média de 3,60 MPa e as caracterizações por DRX, MEV e EDS confirmaram o desenvolvimento de estruturas resultantes das reações de álcali-ativação. Concluiu-se também que a cura térmica inibiu a ocorrência de eflorescência nos tijolos. Dessa forma, o estudo mostrou que os tijolos modulares álcali-ativados podem atender os requisitos para serem utilizados na construção civil, especialmente com o uso da escória de alto forno, reaproveitando um resíduo industrial, contribuindo para um desenvolvimento sustentável.
With the growing demand from civil construction for new materials that preferentially minimize environmental impacts and also meet technical requirements, the soil-cement brick, commercially known as ecological brick, appears as an alternative to the burnt clay brick, which generates impact through its process of burning and energy consumption. When analyzing the soil-cement brick there are economic, social and environmental benefits in its production, however, it still has the cement, which is a component that contributes to the environmental impact. Studies demonstrates that there are possibilities for cement replacement in its production and the technique with promising results is the alkali-activation. Considering the possibilities, the present work proposed the production of a modular brick with compressed and stabilized soil using the alkali-activation technique in real scale. Then, 4 variations of raw materials and production methodologies were studied, involving a fixed matrix of soil and sand, metakaolin or blast furnace slag as precursors, simple activator with NaOH solution or compound with the addition of hydrated lime, with or without thermal curing. From the mechanical and physical characterizations of the bricks it was possible to conclude that the production involving metakaolin as a precursor, composite activator, with thermal cure and the production with blast furnace slag as a precursor, simple activator, with thermal cure, achieve with all the requirements established by standard ABNT NBR 8491:2012 used as a reference. The bricks with blast furnace slag reached the highest compressive strength values with an average of 3.60 MPa and the characterizations by DRX, MEV and EDS confirmed the development of structures resulting from the alkali-activation reactions. It was also concluded that thermal curing inhibited the occurrence of efflorescence on the bricks. Thus, the study demonstrated that alkali-activated modular bricks can achieve the requirements for use in civil construction, especially with the use of blast furnace slag, reusing industrial waste, contributing to sustainable development
With the growing demand from civil construction for new materials that preferentially minimize environmental impacts and also meet technical requirements, the soil-cement brick, commercially known as ecological brick, appears as an alternative to the burnt clay brick, which generates impact through its process of burning and energy consumption. When analyzing the soil-cement brick there are economic, social and environmental benefits in its production, however, it still has the cement, which is a component that contributes to the environmental impact. Studies demonstrates that there are possibilities for cement replacement in its production and the technique with promising results is the alkali-activation. Considering the possibilities, the present work proposed the production of a modular brick with compressed and stabilized soil using the alkali-activation technique in real scale. Then, 4 variations of raw materials and production methodologies were studied, involving a fixed matrix of soil and sand, metakaolin or blast furnace slag as precursors, simple activator with NaOH solution or compound with the addition of hydrated lime, with or without thermal curing. From the mechanical and physical characterizations of the bricks it was possible to conclude that the production involving metakaolin as a precursor, composite activator, with thermal cure and the production with blast furnace slag as a precursor, simple activator, with thermal cure, achieve with all the requirements established by standard ABNT NBR 8491:2012 used as a reference. The bricks with blast furnace slag reached the highest compressive strength values with an average of 3.60 MPa and the characterizations by DRX, MEV and EDS confirmed the development of structures resulting from the alkali-activation reactions. It was also concluded that thermal curing inhibited the occurrence of efflorescence on the bricks. Thus, the study demonstrated that alkali-activated modular bricks can achieve the requirements for use in civil construction, especially with the use of blast furnace slag, reusing industrial waste, contributing to sustainable development
Descrição
Palavras-chave
Tijolo ecológico, Geopolímero, Álcali-ativação, Metacaulim, Escória de alto forno, Ecological brick, Geopolymer, Geopolymer, Alkali-activation, Blast furnace slag