Influência das condições de mistura e moldagem na permeabilidade de concretos refratários aluminosos

• Ano de defesa: 2008
• Autor(a) principal: Henrique Jardim Raad
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Concreto; Permeabilidade; Construção civil; Cimento de alumina; Concreto Análise; Engenharia civil; Concreto Permeabilidade
• Link de acesso: http://hdl.handle.net/1843/ISMS-7NHKUG

The factors mixture water grade and launch method have great influence on final characteristics of refractory concrete in the fresh and harden states considering its performance in relation to launch and utilization conditions, being, besides aspects like the lost of mechanical resistance, directs agents on the appearance of pores and microfissures, elements responsible to material permissiviness, harmful material penetration and its mineral and crystalline structure. Other aspects, related to the industrial dosage, can also influence in these phenomenons like, for example, the form and reactivity of addition of thin powders which can be essential for good performance of the refractory concrete mixture when it is extracted the conscious use of additives from them. This work has searched evaluate the influence of three variables: water grade, vibration method, qualitative and quantitative variations of thin dust on the appearance of pores in aluminous refractory concretes of low cement grade and the results related to the growth of permeability seen from them. Samples derived of a concrete utilized on industrial refractories have been collected and they have been correlated with the analyzed standard material. The variations have been divided in twelve main groups, by three factors, which have been done tests related to the penetration of gases and water in these materials and compared for the verification of influence of the variables on the behavior of the samples. The results have showed the great influence of mixture water grade on the appearance of opened and close pores of the materials, being these the main responsible for the generation phenomenon of pores. In the background, it have been evidenced that the influence of vibration conditions on the appearance of pores in the material is much smaller than the influence of the variable water grade although being very significant. The qualitative variation of thin powders has alto resulted in the appearance of pores due to the lost of fluidity and packing properties. The quantitative variation of theses has showed great importance of them for the huge reduction of the pore volume in the material. The efficacy of the tests used in this research has been confirmed and they can be reproduced in local works with little laboratorial structures due to the simplicity of execution.