Made available in DSpace on 2014-12-17T14:07:06Z (GMT). No. of bitstreams: 1
GelsoneideSG_DISSERT.pdf: 1818458 bytes, checksum: 7c978a688725815697ae8981fa5f2d16 (MD5)
Previous issue date: 2013-02-18 / Generally, cellulose ethers improves mortar properties such as water retention, workability and setting time, along with adherence to the substrate. However, a major disadvantage of the addition of cellulose ethers in mortars is the delay in hydration of the cement. In this paper a cellulose phosphate (Cp) was synthesized water soluble and has been evaluated the effect of their incorporation into mortar based on Portland cement. Cellulose phosphate obtained was characterized by spectrophotometry Fourier transform infrared (FTIR), X-ray diffraction (XRD), elemental analysis and scanning electron microscopy (SEM). Mortar compositions were formulated with varying phosphorus content in cellulose and cellulose phosphate concentrations, when used in partial or total replacement of the commercial additive based hydroxyethyl methyl cellulose (HEMC). The mortars formulated with additives were prepared and characterized by: testing in the fresh state (consistency index, water retention, bulk density and air content incorporated) and in the hardened state (absorption by capillarity, density, flexural and compression strength). In mixtures the proportion of sand:cement of 1:5 (v / v) and factor a / c = 1.31 and water were held constant. Overall, the results showed that the celluloses phosphates employed in mortars added acted significantly when partially substituting the commercial additive. With regard to consistency index, water retention and bulk density in the fresh state and absorption by capillarity and bulk density apparent in the hardened state, showed no appreciable differences as compared to the commercial additive. The incorporated air content in the fresh state reduced markedly, but did not affect other properties. The mortars with cellulose phosphate, partially replacing the commercial additive showed an improvement of the properties of flexural strength and compressive strength / Geralmente, ?teres de celulose melhoram as propriedades de argamassas, tais como reten??o de ?gua, trabalhabilidade e o tempo de pega, juntamente com a ades?o ao substrato. No entanto, uma das principais desvantagens da adi??o dos ?teres de celulose nas argamassas ? o retardo na hidrata??o do cimento. Neste trabalho foi sintetizada uma celulose fosfatada (Cp) sol?vel em ?gua e foi avaliado o efeito da sua incorpora??o em argamassa ? base de cimento Portland. A celulose fosfatada obtida foi caracterizada por espectrofotometria de infravermelho por transformada de Fourier (FTIR), difra??o de raios-X (DRX), an?lise elementar, an?lise termogravim?trica (TGA) e microscopia eletr?nica de varredura (MEV). Argamassas com composi??es variando o teor de f?sforo relativamente ? celulose e as concentra??es de celulose fosfatada, quando utilizada em substitui??o parcial ou total do aditivo comercial a base de hidroxietil metil celulose (HEMC). As argamassas formuladas com os aditivos foram preparadas e caracterizadas por: ensaios no estado fresco (?ndice de consist?ncia, reten??o de ?gua, densidade e teor de ar incorporado) e no estado endurecido (absor??o por capilaridade, densidade, resist?ncia ? flex?o e compress?o). Nas misturas a propor??o de areia, cimento e ?gua foram mantidos constantes. De um modo geral, os resultados mostraram que as celuloses fosfatadas empregadas nas argamassas atuaram significativamente quando adicionados parcialmente em substitui??o ao aditivo comercial. No que se refere ao ?ndice de consist?ncia, reten??o de ?gua e densidade de massa no estado fresco e absor??o por capilaridade e densidade de massa aparente no estado endurecido, n?o demonstraram diferen?as apreci?veis comparativamente ao aditivo comercial. O teor de ar incorporado no estado fresco reduziu de forma marcante, mas n?o influenciou as demais propriedades. As argamassas com celulose fosfatada, substituindo parcialmente o aditivo comercial, mostraram uma melhora das propriedades de resist?ncia ? flex?o e de resist?ncia ? compress?o.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/12777 |
| Date | 18 February 2013 |
| Creators | G?is, Gelsoneide da Silva |
| Contributors | CPF:80732810400, http://lattes.cnpq.br/8671649752936793, Paskocimas, Carlos Alberto, CPF:06296687877, http://lattes.cnpq.br/2365059843175411, Almeida, Maria das Vit?rias Vieira de, CPF:52402444487, http://lattes.cnpq.br/7590200701773198, Santos, Am?lia Severino Ferreira e, CPF:59284064104, http://lattes.cnpq.br/5119417295487126, Nascimento, Rubens Maribondo do |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncia e Engenharia de Materiais, UFRN, BR, Processamento de Materiais a partir do P?; Pol?meros e Comp?sitos; Processamento de Materiais a part |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
Page generated in 0.0018 seconds