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Estudo do desempenho, a curto e longo prazo, da incorporação de resíduos industriais nas composições de argamassa e betões de base cimentícia
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Abstract(s)
A argamassa e o betão são dos materiais mais utilizados na indústria da construção civil. A sua aplicação está presente em diversas obras, isto deve-se às suas características no estado fresco - trabalhabilidade e no estado endurecido - durabilidade. O cimento é o principal componente para obter as composições de argamassa e betão, constituindo o ligante que manterá coeso todos os materiais. É do conhecimento geral que a produção de cimento é uma das atividades responsáveis pela grande emissão de CO2 para a atmosfera. Com recurso a adições de Cinzas de Fundo (CF) consegue-se contribuir para minimizar um problema de impacto ambiental e melhorar a economia do projecto. A adição de Cinzas de Fundo permite reduzir a quantidade de cimento utilizado nas composições de argamassa e betões. A presente dissertação teve como principal objectivo analisar o desempenho de argamassas e betões com substituição de cimento Portland CEM I 42,5R por CF. Proceder-se-á a avaliação da eficiência de adições de Cinzas de Fundo, com substituição de 10%, 15% e 20% , provenientes de uma central termoelétrica, recorrendo a ensaios em provetes prismáticos para as composições de argamassa, e para as composições de betão foram feitos provetes cubicos e cilindricos. Realizaram-se ensaios de forma a caracterizar argamassas de base cimentícia quanto ao seu desempenho no estado fresco e no estado endurecido, garantindo a trabalhabilidade das argamassas e dos betões através da introdução de dosagens de superplastificante. Nos ensaios no estado fresco verifica-se que a inclusão de CF aumenta o volume de pasta de ligante, que será benéfico para as características da argamassa, como a trabalhabilidade, provocando uma melhoria na sua plasticidade e coesão. Em relação ao estado endurecido, o comportamento mecânico das composições com adição de CF melhora em termos de flexão, mas em relação à compressão verifica-se um decréscimo de resistência – para as argamassas com adição de 10% de CF a resistência á compressão é cerca de 90% de uma argamassa de referência. Em relação as adições de 15 e 20% não se verifica uma variação significativa na resistência o que torna vantajoso a utilização de 20% de CF. Com este estudo, obteve-se como principal conclusão que a adição de Cinzas de Fundo influencia o comportamento da argamassa e do betão. E verifica-se que é possível em alguns casos substituir até 20% da massa de Cimento por CF.
The mortar and concrete are the most widely used materials in the construction industry. Its application is present in several works , this is due to its characteristics in the fresh state - workability and hardened state - durability. Cement is the main component for the compositions of mortar and concrete , forming the cohesive bond that will hold all materials. It is common knowledge that cement production is one of the activity responsible for the vast emission of CO2 to the atmosphere. Using the additions of ash Fund ( CF ) is achieved contributing to a problem of minimizing environmental impact and improve the economics of the project . The addition of bottom ash reduces the amount of cement used in mortar and concrete compositions . This work had as main objective to analyze the performance of mortar and concrete with replacement of Portland cement CEM I 42,5 R for CF . Evaluating the efficiency of additions of ash Fund shall be made - with substitution of 10 % , 15 % and 20 % , from a thermoelectric plant , using tests for compositions prismatic mortar specimens , and the compositions concrete cubic and cylindrical specimens were made . Assays were performed in order to characterize cementitious mortars on their performance in fresh and hardened state , ensuring the workability of mortar and concrete by introducing dosages of superplasticizer . In the experiments in the fresh state it appears that the inclusion of CF increase the volume of binder folder, which will be beneficial for the characteristics of mortar , as the workability , causing an improvement in their plasticity and cohesion. Regarding the hardened state , the mechanical compositions with the addition of CF improvement in terms of bending, but in relation to the compression behavior There was a decrease in resistance - for the mortars with addition of 10% CF resistance to compression walks by 90% of a reference mortar . Regarding the additions of 15 and 20% takes place without significant change in resistance which makes advantageous use of 20% CF . With this study , we obtained the main conclusion that the addition of ash background influences the behavior of mortar and concrete . And it is found that in some cases it is possible to replace up to 20 % by weight of cement per CF.
The mortar and concrete are the most widely used materials in the construction industry. Its application is present in several works , this is due to its characteristics in the fresh state - workability and hardened state - durability. Cement is the main component for the compositions of mortar and concrete , forming the cohesive bond that will hold all materials. It is common knowledge that cement production is one of the activity responsible for the vast emission of CO2 to the atmosphere. Using the additions of ash Fund ( CF ) is achieved contributing to a problem of minimizing environmental impact and improve the economics of the project . The addition of bottom ash reduces the amount of cement used in mortar and concrete compositions . This work had as main objective to analyze the performance of mortar and concrete with replacement of Portland cement CEM I 42,5 R for CF . Evaluating the efficiency of additions of ash Fund shall be made - with substitution of 10 % , 15 % and 20 % , from a thermoelectric plant , using tests for compositions prismatic mortar specimens , and the compositions concrete cubic and cylindrical specimens were made . Assays were performed in order to characterize cementitious mortars on their performance in fresh and hardened state , ensuring the workability of mortar and concrete by introducing dosages of superplasticizer . In the experiments in the fresh state it appears that the inclusion of CF increase the volume of binder folder, which will be beneficial for the characteristics of mortar , as the workability , causing an improvement in their plasticity and cohesion. Regarding the hardened state , the mechanical compositions with the addition of CF improvement in terms of bending, but in relation to the compression behavior There was a decrease in resistance - for the mortars with addition of 10% CF resistance to compression walks by 90% of a reference mortar . Regarding the additions of 15 and 20% takes place without significant change in resistance which makes advantageous use of 20% CF . With this study , we obtained the main conclusion that the addition of ash background influences the behavior of mortar and concrete . And it is found that in some cases it is possible to replace up to 20 % by weight of cement per CF.
Description
Mestrado em Engenharia Civil
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Publisher
Escola Superior de Tecnologia do Barreiro