Silica Fume
Mostrando 13-24 de 46 artigos, teses e dissertações.
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13. Avaliação das propriedades de transporte de massa contendo adições minerais / Evaluation of the mass transport containing mineral admixtures
The durability of reinforced concrete structures is damaged by the degrading action of the penetration of substances in the form of gases, vapors and liquids through the pores and cracks. It is known that water both in its pure form or containing dissolved ions such as chloride, sulphate, carbon dioxide or oxygen ions, can compromise the durability of concre
Publicado em: 2009
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14. Evaluation of the ability to protect against corrosion of the gun hard-induced chloride concrete with mineral additions and corrosion inhibitors / Avaliação da capacidade de proteção contra a corrosão da arma-dura induzida por cloretos de concretos com adições minerais e inibidores de corrosão
O aumento da durabilidade é um aspecto primordial para os elementos estruturais de concreto, em especial aqueles constituintes das estruturas de geração de energia em parques eólicos, sujeitos ao fenômeno de corrosão das armaduras. Nesse contexto, este trabalho tem como objetivo geral avaliar a capacidade de proteção de diferentes concretoS frente ao
Publicado em: 2009
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15. Estudo da influência das adições minerais no comportamento do concreto sob a ação do fogo
The present study assessed the behavior of concrete produced from mineral additions when subjected high temperatures typical occurrence in fire. Representative speciments were shaped using only Portland cement CP V- ARI as binder, and others, with the same amount of binder, but replacement cement by mineral additions like blast furnace slag low reativity, bl
Publicado em: 2008
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16. Avaliação da retração autógena em concretos de alto desempenho com diferentes adições
High performance concrete is commonly useful by its performance, strength, durability, workability and others. Autogenous shrinkage can be considering one of the reasons of cracks on high performance concretes at early ages. The concrete shrinkage can be influenced by different reasons: piece measurements, water content of mashing, dosage of cement, inert na
Publicado em: 2008
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17. Otimização e análise mecânica de pastas geopoliméricas para uso em poços sujeitos à injeção cíclica de vapor
Oil wells subjected to cyclic steam injection present important challenges for the development of well cementing systems, mainly due to tensile stresses caused by thermal gradients during its useful life. Cement sheath failures in wells using conventional high compressive strength systems lead to the use of cement systems that are more flexible and/or ductil
Publicado em: 2008
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18. Estudo para a reutilização do resíduo sólido constituído pelas areias de fundição aglomeradas com argila, através da técnica de solidificação/estabilização em matrizes de cimento Portland, para aplicação no setor da construção civil / Study to reuse a solid waste generated by foundry sands bonded with clay, through solidification/stabilization in Portland cement matrices technic, for implementation in the construction industry
In this research, a study that investigates the technical feasibility for the recycling of solid waste generated by the disposal of the foundry sands bonded with clay, for implementation in the construction industry, was conducted. For this reason, the work establishes a method, which assesses the stabilization of waste in solidified matrices of Portland cem
Publicado em: 2008
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19. AVALIAÇÃO DO DESEMPENHO DE CONCRETOS COM ADIÇÕES MINERAIS QUANTO À CORROSÃO DAS ARMADURAS INDUZIDA POR CLORETOS / Performance evaluation of concretes content with mineral additions in relation to the reinforcing steels corrosion induced by chlorides
O presente trabalho tem como objetivo estudar o desempenho de concretos quanto à ação de íons cloreto, avaliando tanto a interveniência das adições minerais incorporadas ao concreto quanto da relação água/aglomerante (a/ag), considerando aspectos cinéticos e termodinâmicos do fenômeno corrosivo. Para tanto, desenvolveu-se uma pesquisa experiment
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/08/2007
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20. Effect of silica fume and SBR latex on the pasteaggregate interfacial transition zone
This paper deals with the effect of silica fume and styrene-butadiene latex (SBR) on the microstructure of the interfacial transition zone (ITZ) between Portland cement paste and aggregates (basalt). Scanning Electron Microscope (SEM) equipped with energy dispersive x ray analysis system (EDX) was used to determine the ITZ thickness. In the plain concrete a
Materials Research. Publicado em: 2007-03
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21. Efeito de adições ativas na mitigação das reações álcali-sílica e álcali-silicato. / Effect of mineral admixtures in controlling the alkali-silica reaction and alkali-silicate reaction.
The alkali-aggregate reaction is a pathologic manifestation that can induce the premature distress and loss in serviceability of concrete structures affected. It is directly associated to the selection of materials (cement, coarse and fine aggregates, water and additives), as the interaction between these materials and environmental condition will grant the
Publicado em: 2007
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22. AVALIAÇÃO DO DESEMPENHO DE CONCRETOS COM ADIÇÕES MINERAIS QUANTO À CORROSÃO DAS ARMADURAS INDUZIDA POR CLORETOS / Performance evaluation of concretes content with mineral additions in relation to the reinforcing steels corrosion induced by chlorides
The present work aims to study the performance of concrete with regard to the action of chloride ions, evaluating the influence of both mineral additions and water/binder ratio (w/b), considering kinetic and thermodynamic aspects of the corrosive phenomenon. A experimental research was carried out considering the following variables: the presence of mineral
Publicado em: 2007
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23. Contribuição ao estudo da carbonatação do concreto com adição de sílica ativa em ambiente natural e acelerado
Devido à preocupação com a durabilidade das estruturas de concreto armado surgiram novas linhas de pesquisa destacando-se, dentre elas, a previsão de vida útil. Estes estudos deram origem a diversos modelos que tentam estabelecer o comportamento do concreto quando exposto a ambientes agressivos durante um determinado período. Existem várias maneiras d
Publicado em: 2007
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24. Carbonation action in reinforced concrete beams under stress regime carried out on full and small scales / Ação da carbonatação em vigas de concreto armado em serviço, construídas em escala natural e reduzida
This work reports on the behavior of carbonation in reinforced concrete beams under stress regime on full and small scales having the lowest possible frame. The beams were made with and without adding silica from rice husk and silica fume (Fe-Si). For each beam on a full scale (coarse aggregate with D máx. = 19 mm) another beam on a small scale was made wit
Publicado em: 2007