Análise das propriedades reológicas de materiais cimentícios associando o conceito de empacotamento de partículas
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Data
2013-08-16
Autores
Oliveira, Caroline Oliveira e [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O concreto de alto desempenho (CAD) e o concreto auto adensável (CAA) são materiais que apresentam características específicas, as quais superam as deficiências do concreto convencional. Para que esses concretos atendam, da melhor forma possível, suas características específicas, uma cuidadosa dosagem dos seus componentes deve ser realizada, para tanto, pode-se empregar os conceitos de reologia e de empacotamento de partículas. Assim, foi realizado nesta pesquisa um estudo de dosagens dos concretos de alto desempenho e auto adensável utilizando os conceitos de reologia e de empacotamento de partículas. Com base nos conceitos de reologia foram determinados os teores ótimos de sílica ativa e de aditivo superplastificante por meio do estudo reológico das pastas de cimento e das argamassas, onde foram empregados os ensaios de fluidez com o cone de Marsh e o reométrico clássico, sendo este último realizado com o reômetro R/S do tipo cilindro coaxial. Por outro lado, com base nos conceitos de empacotamento de partículas foi determinada a proporção ótima dos componentes particulados por meio de um programa computacional fundamentado no modelo de Alfred. Realizada a dosagem dos concretos, procurou-se analisar as propriedades reológicas de suas pastas de cimento e argamassas, verificando a influência dos conceitos de empacotamento, além de avaliar a resistência à compressão e o custo das composições de concreto. Os concretos dosados em ambos os conceitos apresentaram no estado fresco resultados satisfatórios, já no estado endurecido o CAD dosados com base nos conceitos de empacotamento de partícula apresentou resistência aos 28 dias superior, ao contrario do CAA, que não obteve melhora de resistência. Na caracterização reológica das pastas e argamassas, o emprego do empacotamento provocou um aumento da fluidez facilitando o escoamento.
The high performance concrete (HPC) and self-compacting concrete (SCC) are materials that have specific features, which outweigh the shortcomings of conventional concrete. For these concretes meet, in the best way possible, their specific characteristics, a careful dosage of its components must be held, for both, one can employ the concepts of rheology and particle packing. Thus, this work was realized a study of dosages of high performance concrete and self-compacting concrete, using the concepts of rheology and particle packing. Based on the concepts of rheology were determined optimum levels of silica fume and of superplasticizer admixture by the rheologic study of the cement pastes and mortars, where were employed the fluidity test with Marsh cone and the rheometric test, the latter being carried out with the coaxial cylinder rheometer R/S. On the other hand, based on the concepts of particle packing was determined the optimum proportion of particulate components by means of a computer program based on the model of Alfred. Held the dosage of the concretes, tried to analyze the rheological properties of its cement pastes and mortars, checking the influence of packing concepts, besides evaluate the compressive strength and the cost of concrete compositions. The concretes dosed in both concepts presented, in a fresh state, satisfactory results, on the other hand in the hardened state, HPC dosed based on the concepts of particle packing showed strength to more than 28 days, unlike the SCC, which did not improve strength. In rheological characterization of pastes and mortars, the use of packing caused an increase fluidity facilitating the flow.
The high performance concrete (HPC) and self-compacting concrete (SCC) are materials that have specific features, which outweigh the shortcomings of conventional concrete. For these concretes meet, in the best way possible, their specific characteristics, a careful dosage of its components must be held, for both, one can employ the concepts of rheology and particle packing. Thus, this work was realized a study of dosages of high performance concrete and self-compacting concrete, using the concepts of rheology and particle packing. Based on the concepts of rheology were determined optimum levels of silica fume and of superplasticizer admixture by the rheologic study of the cement pastes and mortars, where were employed the fluidity test with Marsh cone and the rheometric test, the latter being carried out with the coaxial cylinder rheometer R/S. On the other hand, based on the concepts of particle packing was determined the optimum proportion of particulate components by means of a computer program based on the model of Alfred. Held the dosage of the concretes, tried to analyze the rheological properties of its cement pastes and mortars, checking the influence of packing concepts, besides evaluate the compressive strength and the cost of concrete compositions. The concretes dosed in both concepts presented, in a fresh state, satisfactory results, on the other hand in the hardened state, HPC dosed based on the concepts of particle packing showed strength to more than 28 days, unlike the SCC, which did not improve strength. In rheological characterization of pastes and mortars, the use of packing caused an increase fluidity facilitating the flow.
Descrição
Palavras-chave
Concreto auto-adensível, Reologia, Concreto, Materiais de construção, Concrete
Como citar
OLIVEIRA, Caroline Oliveira e. Análise das propriedades reológicas de materiais cimentícios associando o conceito de empacotamento de partículas. 2013. . Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Engenharia de Ilha Solteira, 2013.