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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estudo de concretos autoadens?veis com reduzidos teores de cimento e elevados teores de adi??es minerais / Incorporation of the residue originating from the improvement of kaolin in asphalt concrete

Medeiros, Fernanda Karolline de 06 May 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-10-26T23:26:58Z No. of bitstreams: 1 FernandaKarollineDeMedeiros_DISSERT.pdf: 19864930 bytes, checksum: c1a9710c22ffc5b38808a1f60d117073 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-12-26T19:38:47Z (GMT) No. of bitstreams: 1 FernandaKarollineDeMedeiros_DISSERT.pdf: 19864930 bytes, checksum: c1a9710c22ffc5b38808a1f60d117073 (MD5) / Made available in DSpace on 2016-12-26T19:38:47Z (GMT). No. of bitstreams: 1 FernandaKarollineDeMedeiros_DISSERT.pdf: 19864930 bytes, checksum: c1a9710c22ffc5b38808a1f60d117073 (MD5) Previous issue date: 2016-05-06 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O processo de produ??o de concreto gera um significativo impacto ambiental por ser um dos maiores consumidores de mat?ria-prima, como areia, pedra, cascalho mo?do e ?gua. Entretanto, o maior impacto ? causado pela produ??o do cimento Portland, material indispens?vel ao concreto. Materiais como a cinza do baga?o da cana-de-a??car, s?lica da casca de arroz, metacaulim e s?lica ativa, s?o adi??es minerais que desempenham importante papel nas propriedades de resist?ncia e de durabilidade, quando utilizados em mistura com cimento Portland e, sob certas condi??es, podem perfeitamente substituir altos teores cimento nas misturas, conferido a elas, al?m dos benef?cios conhecidos que a redu??o de cimento acarreta, aumento significativo de durabilidade. A utiliza??o de concreto autoadens?vel (CAA) tem crescido significativamente por suas caracter?sticas de alta fluidez e coes?o e pela possibilidade de moldagem in loco sem vibra??o, formando um produto livre de vazios e falhas e que apresenta tamb?m, capacidade de fluxo atrav?s do seu peso pr?prio preenchendo completamente as f?rmas e atingindo a compacta??o mesmo em estruturas densamente armadas. Frente ao exposto, este trabalho se prop?s avaliar as propriedades reol?gicas, f?sicas, mec?nicas e de durabilidade dos eco-concretos autoadens?veis com a incorpora??o de altos teores de cinza da biomassa da cana-de-a??car, s?lica da casca de arroz e metacaulim. Para isso, foram analisados concretos com incorpora??o de 40% e 50% e um concreto autoadens?vel com materiais convencionais sem adi??es minerais para utiliza??o como refer?ncia. Os resultados evidenciaram que a sinergia resultante das misturas desenvolvidas revelou desempenhos mec?nicos e de durabilidade superiores ao CAA de refer?ncia, concluindo-se ent?o que ? poss?vel produzir concretos autoadens?veis com desempenhos promissores e com redu??o significativa do consumo de cimento para n?veis de cerca 220 kg / m3, contribuindo assim para a sustentabilidade da ind?stria da constru??o, minimizando energia liberada e a compacta??o. / The concrete production process generates a significant environmental impact as one of the largest consumers of raw materials, like sand, stone and water. However, the greatest impact is caused by the production of Portland cement, an essential material to the concrete. Materials such as sugarcane bagasse ashes (RBC), silica from rice husk (PCA), metakaolin (MK) and silica fume, are mineral additions that play an important role in resistance and durability properties, when used in combination with Portland cement and, under certain conditions, can perfectly replace high cement content in mixtures, given to them in addition to the known benefits that cement reduction entails, like significant increase in durability. The use of self-compacting concrete (SCC) has grown significantly by its high fluidity characteristics and cohesiveness and the possibility of forming in situ without vibration, forming a fault and void-free product which has also flowability by its own weight completely filling the molds and reaching compaction even in heavily armed structures. Based on these, this study aimed to evaluate the rheological, physical, mechanical and durability properties of self-compacting eco-concrete with the high percentage incorporation of sugarcane biomass ashes, silica from rice husk and metakaolin. Based on these, this study evaluated the rheological properties, physical, mechanical and durability freight to attack by chloride ions of self-compacting ecoconcrete with the incorporation of high content of ash biomass sugarcane, rice husk silica and metakaolin. For this, a self-compacting concrete with conventional materials without mineral admixtures for use as a reference and four concrete incorporating 40% and 50% additions were analyzed using gray bagasse from sugarcane, pozzolan rice husk and metakaolin. The results showed that the resulting synergy of developed mixtures revealed mechanical and durability performance, freight to attack by chloride ions, above the reference SCC. When compared to the reference concrete, concrete with additions showed an increase of up to 13.4% of the compressive strength at 28 days and reducing to 87% the penetration of chloride ions to 91 days. The results of the study also showed that incorporating high volumes of mineral additions in the SCC causes a reduction of the environmental impact generated by the anthropogenic emissions of CO2, the energy consumed and the consumption of natural materials, thus confirming the relevance of the research. It is possible to produce self-compacting concrete with promising performances, using high RBC levels, PCA and MK, with a significant reduction in cement consumption to levels of about 220 kg / m3, thus contributing to the sustainability of the construction industry, minimizing energy released and compression.

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