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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 concreteMedeiros, Fernanda Karolline de 06 May 2016 (has links)
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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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