Estudo do comportamento físico e mecânico de concretos com diferentes materiais pozolânicos com enfoque na resistência à carbonatação
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Data
2021-07
Autores
Orientador
Köhler, Débora Pedroso Righi
Banca
Schmitz, Rebeca Jéssica
Berton, Júlia Giordani
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Resumo
Este estudo teve como objetivo avaliar as características físicas e mecânicas de concretos com a substituição do cimento por diferentes materiais pozolânicos, verificando também a resistência à carbonatação, por meio de ensaio de carbonatação acelerada. Para a realização desta pesquisa, a dosagem dos concretos foi realizada pelo método ABCP, sendo moldados 15 corpos de prova para cada traço, sendo 4 no total, divididos em traço referência (sem nenhuma adição) na proporção 1;2,53;3,54;0,65, e outros 3 traços com a substituição de 10% de cimento por sílica ativa, metacaulim e cinza volante, respectivamente, todos na proporção 0,90;0,10;2,53;3,54;0,65, com abatimento resultante de 100 mm para todos os traços. Para a validação dos resultados, os corpos de prova foram submetidos ao ensaio de resistência à compressão nas idades de 7, 14 e 56 dias, além do ensaio de absorção por capilaridade por 72 horas, para as idades de 28 dias com cura em câmara úmida e 63 dias, dos quais 7 dias ficaram em cura úmida e 56 dias carbonatando. Para a carbonatação, os corpos de prova foram mantidos nas condições do ensaio, em câmara de carbonatação acelerada com 6% de concentração de CO2 por 56 dias, sendo a profundidade carbonatada medida por meio de indicador de pH. Os resultados obtidos para todos os ensaios foram satisfatórios, sendo possível estabelecer uma relação entre os parâmetros de absorção por capilaridade e resistência à compressão, com a profundidade de carbonatação. Os traços com adição de metacaulim e cinza volante apresentaram os resultados mais promissores, com as maiores resistências à compressão, menores índices de absorção, além de apresentarem uma redução na profundidade de carbonatação em relação ao concreto referência. Entretanto, o traço com a adição de sílica ativa reduziu a resistência à compressão e a absorção por capilaridade em relação ao traço de referência, diminuindo também a resistência do concreto frente à carbonatação, apresentando a maior profundidade carbonatada dentre todos os traços estudados.
The objective of this study was to evaluate the physical and mechanical characteristics of the concrete with the partial replacement of cement by different pozzolanic materials, also verifying the resistance to carbonation, through an accelerated carbonation test. To carry out this work, the dosage of concrete was executed by the ABCP method, with 15 concrete test samples being molded for each recipe, being 4 in total, divided into the reference recipe (without any addition) in the proportion of 1;2.53;3, 54;0.65, and other 3 recipes with the replacement of 10% of cement by silica fume, metakaolin and fly ash, respectively, all in the proportion of 0.90;0.10;2.53;3.54;0,65, with the resulting slump of 100mm for all recipes To validate the results, the test samples were submitted to the compressive strength test at the ages of 7, 14 and 56 days, as well as the absorption by capillarity test for 72 hours, for the ages of 28 days being cured in a humid chamber, and 63 days, of which 7 days the healing process occurred in the humid chamber, and for the remaining 56 days, the samples were carbonated. For carbonation purposes, the concrete samples were kept under the conditions of the test, in an accelerated carbonation chamber with 6% concentration of CO2 for 56 days, and the carbonated depth was measured with a pH indicator. The results obtained for all tests were satisfying, being possible to establish a link between the parameters of capillarity absorption and compressive strength, with the carbonation depth. The concrete recipes with the addition of metakaolin and fly ash showed the most promising results, with the highest compressive strength, lowest absorption indices, as well as being able to reduce the carbonation depth when compared to the reference concrete. However, the recipe with the addition of silica fume reduced both the compressive strength and capillarity absorption when compared to the reference recipe, but it also decreased the strength of the concrete against carbonation, resulting in the concrete with the greatest carbonated depth amongst all of the studied concrete recipes.
The objective of this study was to evaluate the physical and mechanical characteristics of the concrete with the partial replacement of cement by different pozzolanic materials, also verifying the resistance to carbonation, through an accelerated carbonation test. To carry out this work, the dosage of concrete was executed by the ABCP method, with 15 concrete test samples being molded for each recipe, being 4 in total, divided into the reference recipe (without any addition) in the proportion of 1;2.53;3, 54;0.65, and other 3 recipes with the replacement of 10% of cement by silica fume, metakaolin and fly ash, respectively, all in the proportion of 0.90;0.10;2.53;3.54;0,65, with the resulting slump of 100mm for all recipes To validate the results, the test samples were submitted to the compressive strength test at the ages of 7, 14 and 56 days, as well as the absorption by capillarity test for 72 hours, for the ages of 28 days being cured in a humid chamber, and 63 days, of which 7 days the healing process occurred in the humid chamber, and for the remaining 56 days, the samples were carbonated. For carbonation purposes, the concrete samples were kept under the conditions of the test, in an accelerated carbonation chamber with 6% concentration of CO2 for 56 days, and the carbonated depth was measured with a pH indicator. The results obtained for all tests were satisfying, being possible to establish a link between the parameters of capillarity absorption and compressive strength, with the carbonation depth. The concrete recipes with the addition of metakaolin and fly ash showed the most promising results, with the highest compressive strength, lowest absorption indices, as well as being able to reduce the carbonation depth when compared to the reference concrete. However, the recipe with the addition of silica fume reduced both the compressive strength and capillarity absorption when compared to the reference recipe, but it also decreased the strength of the concrete against carbonation, resulting in the concrete with the greatest carbonated depth amongst all of the studied concrete recipes.
Descrição
Palavras-chave
Carbonatação; Carbonatação acelerada; Concentração de CO2; Câmara de carbonatação; Pozolanas; Carbonation; Accelerated carbonation; Concentration of CO2; Carbonation chamber; Pozzolanic materials
Citação
BRESOLIN, Augusto Magri. Estudo do comportamento físico e mecânico de concretos com diferentes materiais pozolânicos com enfoque na resistência à carbonatação. 2021. Monografia (Graduação em Engenharia Civil) – Universidade do Vale do Taquari - Univates, Lajeado, 01 jul. 2021. Disponível em: http://hdl.handle.net/10737/3244.