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Previous issue date: 2016-12-15 / O concreto autoadens?vel (CAA) possui elevado teor de materiais finos e vem sendo bastante utilizado devido as suas caracter?sticas de alta fluidez e coes?o. Os finos provindos de res?duos ou subprodutos industriais podem vir a ser usados em prol da sustentabilidade, minimizando consideravelmente o consumo de cimento associado ? possibilidade de manter, ou melhorar, as propriedades mec?nicas ou de durabilidade. Desta forma, o presente trabalho investigou a viabilidade do desenvolvimento de CAA?s confeccionados com elevados teores de adi??es minerais e cal hidratada. Para isso, o cimento foi substitu?do por adi??es minerais (pozolana da casca do arroz, metacaulim e f?ler calc?rio) no teor de 60%, com base no tra?o de refer?ncia com consumo de 451,1 kg/m? de cimento, originando novos tra?os com consumos de cimento entre 167,7 kg/m? e 173,3 kg/m?. A cal hidratada foi incorporada como adi??o em tr?s tra?os no teor de 5% sobre a massa total dos materiais finos. Os CAA?s foram caracterizados no estado fresco pelos ensaios de espalhamento, T500, anel-J, funil-V e caixa-L. Para avalia??o do desempenho mec?nico dos CAA?s foram realizados ensaios de resist?ncia ? compress?o, velocidade do pulso ultrass?nico e m?dulo de elasticidade est?tico, bem como propriedades de transporte relacionadas ? durabilidade: absor??o por capilaridade, difus?o de ?ons cloreto, resistividade el?trica e carbonata??o. Os CAA?s com adi??es minerais apresentaram desempenho mec?nico satisfat?rio, embora inferiores ao do tra?o de refer?ncia. As resist?ncias ? compress?o aos 28 dias dos concretos com adi??es minerais apresentaram redu??o de 15 a 60% em rela??o ao tra?o de refer?ncia, mas todos os resultados foram compat?veis com concretos estruturais de acordo com os requisitos da NBR 6118 (ABNT, 2014). Com rela??o a durabilidade, os concretos com adi??es minerais apresentaram redu??o do coeficiente de difus?o de ?ons cloreto que variaram entre 25,4% e 74,8%. As resistividades el?tricas do concreto de refer?ncia foram bastante inferiores ?s dos concretos com adi??es minerais, mas todas as composi??es estudadas foram classificadas como prov?vel taxa de corros?o desprez?vel. As resistividades el?tricas sofreram grande redu??o quando analisadas em amostras carbonatadas. J? a an?lise da carbonata??o acelerada mostrou que a substitui??o do cimento por adi??es minerais em elevados teores torna os CAA?s bastante suscet?veis a carbonata??o. Quanto a adi??o de cal hidratada, n?o foi verificada influ?ncia positiva no desempenho mec?nico dos CAA?s estudados, mas observou-se que sua utiliza??o proporcionou redu??o da profundidade de carbonata??o nos CAA?s devido a reposi??o da reserva alcalina. / Self-compacting concrete (SCC) has a high content of fine materials and has been widely used due to its characteristics of high fluidity and cohesion. Fines from industrial waste or by-products may be used for the sake of sustainability, considerably reducing the consumption of cement associated with the possibility of maintaining or improving mechanical or durability properties. In this way, the present work investigated the feasibility of the development of SCC's made with high levels of mineral additions and hydrated lime. For this purpose, the cement was replaced by mineral additives (rice husk pozzolan, metakaolin and limestone filer) in the 60% content, based on the reference mixture with consumption of 451.1 kg / m? of cement, giving rise to new mixtures with consumption of cement between 167.7 kg / m? and 173.3 kg / m?. The hydrated lime was incorporated as an addition in three mixtures in the content of 5% on the total mass of the fine materials. The SCC's were characterized in the fresh state by the slump flow test, T500, J-ring, V-funnel and L-box. To evaluate the mechanical performance of the SCC's, tests of compressive strength, ultrasonic pulse velocity and static modulus of elasticity, as well as transport properties related to durability were performed: capillary absorption, chloride ion diffusion, electrical resistivity and carbonation. The SCC's with mineral additions presented satisfactory mechanical performance, although lower than the reference mixture. The compressive strength at 28 days of the concretes with mineral additions showed a reduction of 15 to 60% in relation to the reference mixture, but all the results were compatible with structural concretes according to the requirements of NBR 6118 (ABNT, 2014). Regarding the durability, the concrete with mineral additions presented reduction of the diffusion coefficient of chloride ions that varied between 25.4% and 74.8%. The electrical resistivities of the reference concrete were much lower than those of the concretes with mineral additions, but all the studied compositions were classified as probable negligible corrosion rates. The electrical resistivities suffered great reduction when analyzed in carbonated samples. The analysis of the accelerated carbonation showed that the substitution of cement by mineral additions at high levels makes the SCC very susceptible to carbonation. As for the addition of hydrated lime, there was no positive influence on the mechanical performance of the SCC's studied, but it was observed that its use provided a reduction of the carbonation depth in the SCC's due to the alkaline reserve.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/22289 |
| Date | 15 December 2016 |
| Creators | Fonseca, Thiago Vieira |
| Contributors | 02262184496, http://lattes.cnpq.br/3904325866154130, Almeida, Maria das Vit?rias Vieira, 52402444487, http://lattes.cnpq.br/7590200701773198, N?brega, Ana Cecilia Vieira da, 03226264478, http://lattes.cnpq.br/3109732203611868, Anjos, Marcos Alyssandro Soares dos |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA CIVIL, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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