Avaliação do comportamento físico, mecânico e térmico de blocos de terra comprimida com a substituição do cimento Portland por cinza de bagaço de cana-de-açúcar
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Data
2022-02-10
Autores
Antonelli, Jeferson Fernando Corrêa
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As alternativas sustentáveis para produção de materiais de construção civil são cada vez mais exigidas pela sociedade como resposta às crescentes preocupações mundiais com o meio ambiente. O desenvolvimento de blocos de terra comprimida (BTC) é justificável para minimizar o impacto ambiental no setor de construção civil. O cimento Portland tem sido o material mais usado para estabilização do solo na produção de BTC, entretanto, para sua fabricação é necessário alto fornecimento de energia, e há liberação de grandes quantidades de gases contaminantes durante o processo, tornando a indústria do cimento uma das principais colaboradoras de emissões de CO2, que contribuem para as mudanças climáticas. Diante deste cenário, a substituição parcial ou total do cimento Portland por outros aglutinantes pozolânicos é desejável. A presente pesquisa tem como objetivo avaliar se a substituição parcial de cimento por cinza de bagaço de cana-de-açúcar produz blocos de terra comprimida similares aos confeccionados com cimento Portland em relação aos valores de desempenho físico e mecânico estabelecidos pela NBR 8491 (2012). O estudo de dosagem fixou o teor ideal de cimento para 10% em peso do solo (traço de referência-TR), avaliando os determinantes críticos como resistência à compressão e resistência à absorção de água. Posteriormente foram avaliadas as propriedades físicas, mecânicas, térmicas e de durabilidade de blocos com 10%, 20% e 30% de CBC (T10CBC, T20CBC e T30CBC) em substituição ao cimento. Além disso foi feita a classificação da CBC como material pozolânico através do índice de atividade pozolânica (IAP) por método físico com cimento. Os resultados demonstram que o IAP da CBC superou o valor de referência de 90% estabelecido pela NBR 12653 (2014), atingindo IAP de 113%, confirmando o seu potencial de adição em matrizes cimentícias. A substituição de 10%, 20% e 30% de cimento por CBC satisfaz o critério de resistência à compressão estabelecida pela norma técnica brasileira e outras internacionais. Após os ciclos de molhagem e secagem a resistência à compressão aumentou aproximadamente em 22%, 14%, 25% e 12% para TR, T10CBC, T20CBC e T30CBC respectivamente, em comparação as amostras avaliadas aos 28 dias de idade. Os valores de condutividade térmica variaram de 0,607 à 0,905 (W/mK) e foi constatada a relação direta de densidade com a condutividade térmica. Em termos de resistência e durabilidade o solo argiloso siltoso com alto teor de finos - pobre para compactação – é adequado para produzir BTCs estabilizados com CBC em substituição ao cimento, reduzindo o consumo de cimento, a energia no processo de produção e contribuindo com a diminuição de emissões de poluentes.
Sustainable alternatives for production of building materials are increasingly demanded by society as a response to growing global concerns about the environment. The development of compressed earth blocks (CEB) is justified to minimize the environmental impact in the construction industry. Portland cement has been the most commonly used material for soil stabilization in the production of CEB, however, its manufacture requires high energy supply, and there is the release of large amounts of contaminating gases during the process, making the cement industry a major contributor of CO2 emissions, which contribute to climate change. Given this scenario, the partial or total replacement of Portland cement by other pozzolanic binders is desirable. The present research aims to evaluate whether the partial replacement of cement by sugarcane bagasse ash produces compressed earth blocks similar to those made with Portland cement in relation to the physical and mechanical performance values established by NBR 8491 (2012). The dosage study set the ideal cement content to 10% by weight of soil (reference mixture-TR), evaluating the critical determinants such as compressive strength and resistance to water absorption. Subsequently, the physical, mechanical, thermal, and durability properties of blocks with 10%, 20%, and 30% of SBA (T10CBC, T20CBC, and T30CBC) in cement substitution were evaluated. In addition, the classification of SBA as a pozzolanic material was done through the pozzolanic activity index (PAI) by physical method with cement. The results show that the IAP of SBA exceeded the reference value of 90% established by NBR 12653 (2014), reaching IAP of 113%, confirming its potential for addition in cementitious matrices. The substitution of 10%, 20% and 30% of cement by SBA satisfies the compressive strength criterion established by the Brazilian and other international technical standards. After the wetting and drying cycles, the compressive strength increased by approximately 22%, 14%, 25% and 12% for TR, T10CBC, T20CBC and T30CBC respectively compared to the samples evaluated at 28 days of age. The thermal conductivity values ranged from 0.607 to 0.905 (W/mK) and the direct relationship of density with thermal conductivity was found. In terms of strength and durability, the silty clayey soil with high content of fines - poor for compaction - is suitable for producing BTCs stabilized with SBA as a substitute for cement, reducing cement consumption, energy in the production process and contributing to the reduction of pollutant emissions.
Sustainable alternatives for production of building materials are increasingly demanded by society as a response to growing global concerns about the environment. The development of compressed earth blocks (CEB) is justified to minimize the environmental impact in the construction industry. Portland cement has been the most commonly used material for soil stabilization in the production of CEB, however, its manufacture requires high energy supply, and there is the release of large amounts of contaminating gases during the process, making the cement industry a major contributor of CO2 emissions, which contribute to climate change. Given this scenario, the partial or total replacement of Portland cement by other pozzolanic binders is desirable. The present research aims to evaluate whether the partial replacement of cement by sugarcane bagasse ash produces compressed earth blocks similar to those made with Portland cement in relation to the physical and mechanical performance values established by NBR 8491 (2012). The dosage study set the ideal cement content to 10% by weight of soil (reference mixture-TR), evaluating the critical determinants such as compressive strength and resistance to water absorption. Subsequently, the physical, mechanical, thermal, and durability properties of blocks with 10%, 20%, and 30% of SBA (T10CBC, T20CBC, and T30CBC) in cement substitution were evaluated. In addition, the classification of SBA as a pozzolanic material was done through the pozzolanic activity index (PAI) by physical method with cement. The results show that the IAP of SBA exceeded the reference value of 90% established by NBR 12653 (2014), reaching IAP of 113%, confirming its potential for addition in cementitious matrices. The substitution of 10%, 20% and 30% of cement by SBA satisfies the compressive strength criterion established by the Brazilian and other international technical standards. After the wetting and drying cycles, the compressive strength increased by approximately 22%, 14%, 25% and 12% for TR, T10CBC, T20CBC and T30CBC respectively compared to the samples evaluated at 28 days of age. The thermal conductivity values ranged from 0.607 to 0.905 (W/mK) and the direct relationship of density with thermal conductivity was found. In terms of strength and durability, the silty clayey soil with high content of fines - poor for compaction - is suitable for producing BTCs stabilized with SBA as a substitute for cement, reducing cement consumption, energy in the production process and contributing to the reduction of pollutant emissions.
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Palavras-chave
Bloco de terra comprimida, Cinza de bagaço de cana-de-açúcar, Tijolo ecológico, Tijolo solo-cimento, Bagaço de cana, Tijolos, Produtos ecológicos, Compressed earth block, Sugarcane bagasse ash, Ecological brick, Soil-cement brick