EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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6 resultados
Resultados da Pesquisa
Item Influence of cooling methods on the residual mechanical behavior of fire-exposed concrete : an experimental study.(2019) Carvalho, Espedito Felipe Teixeira de; Silva Neto, João Trajano da; Soares Junior, Paulo Roberto Ribeiro; Maciel, Priscila de Souza; Fransozo, Helder Luis; Bezerra, Augusto Cesar da Silva; Gouveia, Antônio Maria Claret deThis work reports the main conclusions of a study on the mechanical behavior of concrete under ISO 834 fire with different cooling methods. The aim of this research was to provide reliable data for the analysis of structures damaged by fire. The experimental program used cylindrical concrete test specimens subjected to ISO 834 heating in a furnace up to maximum gas temperatures of 400, 500, 600, 700, and 800 ◦C. The compressive strength was measured in three situations: (a) at the different temperature levels reached in the furnace; (b) after a natural cooling process; and (c) after aspersion with water at ambient temperature. The results indicate that the concrete residual compressive strength is fairly dependent on the maximum temperature reached in the furnace and revealed that concrete of a lower strength preserved relatively higher levels of strength. The cooling method significantly influenced the strength, albeit at a lower intensity. In all cases, the residual strength remained in the range of 38% to 67% of the strength at ambient temperature. The statistical analysis showed that the data obtained by the experimental program are significant and confirmed the influence of the conditions imposed on the residual strength.Item Influence of cooling methods on the residual mechanical behavior of fire-exposed concrete : an experimental study.(2019) Carvalho, Espedito Felipe Teixeira de; Silva Neto, João Trajano da; Soares Junior, Paulo Roberto Ribeiro; Maciel, Priscila de Souza; Fransozo, Hélder Luís; Bezerra, Augusto Cesar da Silva; Gouveia, Antônio Maria Claret deThis work reports the main conclusions of a study on the mechanical behavior of concrete under ISO 834 fire with different cooling methods. The aim of this research was to provide reliable data for the analysis of structures damaged by fire. The experimental program used cylindrical concrete test specimens subjected to ISO 834 heating in a furnace up to maximum gas temperatures of 400, 500, 600, 700, and 800 ◦C. The compressive strength was measured in three situations: (a) at the different temperature levels reached in the furnace; (b) after a natural cooling process; and (c) after aspersion with water at ambient temperature. The results indicate that the concrete residual compressive strength is fairly dependent on the maximum temperature reached in the furnace and revealed that concrete of a lower strength preserved relatively higher levels of strength. The cooling method significantly influenced the strength, albeit at a lower intensity. In all cases, the residual strength remained in the range of 38% to 67% of the strength at ambient temperature. The statistical analysis showed that the data obtained by the experimental program are significant and confirmed the influence of the conditions imposed on the residual strength.Item Influence of cooling methods on the residual mechanical behavior of fire-exposed concrete : an experimental study.(2019) Carvalho, Espedito Felipe Teixeira de; Silva Neto, João Trajano da; Soares Junior, Paulo Roberto Ribeiro; Maciel, Priscila de Souza; Fransozo, Hélder Luís; Bezerra, Augusto Cesar da Silva; Gouveia, Alberto Frederico Vieira de SousaThis work reports the main conclusions of a study on the mechanical behavior of concrete under ISO 834 fire with different cooling methods. The aim of this research was to provide reliable data for the analysis of structures damaged by fire. The experimental program used cylindrical concrete test specimens subjected to ISO 834 heating in a furnace up to maximum gas temperatures of 400, 500, 600, 700, and 800 °C. The compressive strength was measured in three situations: (a) at the different temperature levels reached in the furnace; (b) after a natural cooling process; and (c) after aspersion with water at ambient temperature. The results indicate that the concrete residual compressive strength is fairly dependent on the maximum temperature reached in the furnace and revealed that concrete of a lower strength preserved relatively higher levels of strength. The cooling method significantly influenced the strength, albeit at a lower intensity. In all cases, the residual strength remained in the range of 38% to 67% of the strength at ambient temperature. The statistical analysis showed that the data obtained by the experimental program are significant and confirmed the influence of the conditions imposed on the residual strength.Item A relational concept of fire : an innovative strategy for fire safety design.(2018) Gouveia, Antônio Maria Claret de; Bezerra, Augusto Cesar da Silva; Silva Neto, João Trajano da; Castanheira, Luciana Gomes; Villas Boas, Paola de Macedo Gomes Dias; Guimarães, Elaine Mártiles FerreiraThe authors believe that there is a misguided concept regarding high risk fire in many countries. The classic concept of fire is that it is uncontrolled combustion. A new relational concept of fire is proposed herein, where fire is defined as the result of an interactive process between the fire, the building and the occupants. In addition, two design principles are proposed: the initial ignition is fully probabilistic, and the three elements of a fire may be fully designed. The authors discuss the role of design and the genetics of building safety. Conclusions point out that there has been a bad concept of fire during decades of prescriptive design practice. Authors emphasize that this relational concept of fire is a basis for an innovative design for fire safety.Item Resíduo ferroso da indústria mineradora de fosfatados como agregado miúdo em compósitos cimentícios.(2013) Silva, Áureo de Alencar; Resende, Domingos Sávio de; Silva Neto, João Trajano da; Bezerra, Augusto Cesar da Silva; Gouveia, Antônio Maria Claret deNeste estudo foi investigado o comportamento mecânico de compósitos cimenticios confeccionado com a substituição do agregado miúdo quartzoso natural de rio por um resíduo ferroso com predominância de magnetita (Fe3O4) oriundo da extração de rochas fosfáticas (minério de apatita). O minério de apatita é usado na produção de fosfato para a fabricação de fertilizantes na Mesorregião do Alto Paranaíba e Triangulo Mineiro. O resíduo foi caracterizado fisicamente e para avaliar a utilização como agregado miúdo foram confeccionadas argamassas com substituições de 0, 25, 50, 75 e 100%, e concretos com substituições de 0, 25, 50, 100%. Os compósitos tiveram suas propriedades físicas e mecânicas avaliadas. De forma geral, as propriedades dos compósitos foram melhoradas com o aumento da substituição, principalmente no requisito resistência à compressão.Item Sterile clay pozzolans from phosphate mining.(2015) Matos Neto, José Afonso de; Resende, Domingos Sávio de; Silva Neto, João Trajano da; Gouveia, Antônio Maria Claret de; Aguilar, Maria Teresa Paulino de; Bezerra, Augusto Cesar da SilvaThe work presents the characterization of clays from sterile mining of the concentrated phosphatic materials of Araxá in Minas Gerais as pozzolanic materials. Three clays of distinct tones, namely, yellow (YC), red (RC), and intermediate (IC) clays, were used at different levels of excavation depth. The clays were calcined at three temperatures (680, 760, and 840 °C) in a muffle-type electric oven. The pozzolanic activity levels of the calcined clays was measured through the conductivity change in saturated Ca(OH)2 solutions and also from the result of the compressive failure load achieved by mortars with 35% of the Portland cement replaced with the calcined material. The results indicated that the calcined clays showed a high level of pozzolanic activity and can be used as a partial substitute for Portland cement, thus suggesting the possibility of recovering this sterile material.