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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.
81

Efeito das adições de boro na magnetostricção de ligas policristalinas dos sistemas Fe-Al e Fe-Ga / Effect of boron additions on the magnetostriction of polycrystalline alloys of the Fe-Al and Fe-Ga systems

Santos, Claudio Teodoro dos 12 March 2013 (has links)
Os materiais magnetostrictivos apresentam deformação elástica quando são submetidos a um campo magnético ou mudança das propriedades magnéticas quando são submetidos a uma tensão mecânica, e por isso são de grande interesse para aplicações em atuadores, sensores e aproveitadores de energia. Entretanto, os melhores materiais magnetostrictivos disponíveis são caros e frágeis. Nos últimos anos foi descoberta uma nova classe de materiais magnetostrictivos que superam este problema, a classe das ligas Fe-Ga e Fe-Al, que possuem a rara combinação de moderada magnetostricção, boas propriedades mecânicas e baixo custo associado. Atualmente, as pesquisas têm buscado meios de melhorar a magnetostricção destas ligas, tanto por adições ternárias de outros átomos, como pela utilização de diferentes métodos de fabricação, tratamentos térmicos ou processamentos mecânicos. No presente trabalho foi avaliado o efeito das adições de B e do processo de solidificação rápida na magnetostricção e microestrutura das ligas Fe-Al e Fe-Ga. Para isso, ligas policristalinas de composição nominal (Fe80Al20)1-0,01yBy, (Fe80Ga20)1-0,01yBy e (Fe72Ga28)1-0,01yBy, com y = 0; 0,5; 1; 1,5 e 2% at., foram produzidas por fusão a arco e pela técnica de solidificação rápida \"splat cooling\". A caracterização microestrutural das amostras foi realizada no MEV/EDS e DRX. A magnetostricção foi medida com campo magnético de 0 a ±2 T em 4,2, 77 e 300 K, por dilatometria de capacitância. As adições de B ocasionaram a precipitação de Fe2B nos contornos de grão da fase A2 e/ou D03 das ligas Fe-Al e Fe-Ga, resultando na redução do tamanho de grão e formação de cristais dendríticos. As ligas Fe80Al20 apresentaram um valor máximo de magnetostricção de 74 ppm com a adição de 2% at. de B. Já as ligas Fe80Ga20 e Fe72Ga28 apresentaram um máximo com a adição de 1% at. de B, sendo de 81 ppm e 143 ppm, respectivamente. Conclui-se que estas adições de B tiveram um efeito benéfico na magnetostricção das ligas Fe-Al e Fe-Ga como-solidificadas, uma vez que chegaram a ocasionar um aumento de até 100% desta propriedade em relação à liga sem B. Por outro lado, a solidificação rápida não teve efeito sobre a magnetostricção das ligas Fe-Al-B. / Magnetostrictive materials exhibit elastic deformation when subjected to a magnetic field or changing in magnetic properties when subjected to mechanical stress, so they are of great interest for applications in actuators, sensors and energy harvesters. However, the best available magnetostrictive materials are expensive and fragile. In the last years has been discovered a new class of magnetostrictive material which overcome this problem, the class of the Fe-Ga and Fe-Al alloys, which have the unusual combination of moderate magnetostriction, good mechanical properties and low associated cost. Currently, research has searched ways to improve the magnetostriction of these alloys, both for ternary additions of other atoms or by using different methods of preparation, heat treatment or mechanical processing. In the present study, we evaluated the effect of B additions and rapid solidification process on the microstructure and magnetostriction of Fe- Al and Fe-Ga alloys. For this purpose, polycrystalline alloys of nominal composition (Fe80Al20)1-0.01yBy, (Fe80Ga20)1-0.01yBy and (Fe72Ga28)1-0.01yBy, with y = 0, 0.5, 1, 1.5 e 2 at.% were produced by arc melting and splat cooling rapid solidification technique. Microstructural characterization of the samples was performed by SEM/EDS and XRD. The magnetostriction was measured under magnetic field of 0 to ±2 T, at 4.2, 77 and 300 K, by capacitance dilatometry. The B additions caused precipitation of Fe2B at the grain boundaries of A2 and/or D03 phase of Fe-Al and Fe-Ga alloys, resulting in a reduction of the grain size and formation of dendritic crystals. The Fe80Al20 alloys showed a maximum magnetostriction of 74 ppm with the addition of 2 at.% B. And, the Fe80Ga20 and Fe72Ga28 alloys showed a peak with the addition of 1 at.% B, of 81 ppm and 143 ppm, respectively. We concluded that these B additions had a beneficial effect on the magnetostriction of Fe- Al and Fe-Ga as-cast alloys, since they caused an increase up to 100% of this property in relation to the alloy without B. On the other hand, the rapid solidification had no the same effect on the magnetostriction of Fe-Al-B alloys.
82

Aprimoramento na qualidade nutricional da carne mecanicamente separada da tilápia do Nilo e sua aplicação em empanados / Improvement in the quality of nutritional mechanically separated meat of Nile tilapia and its application in patties

Signor, Flávia Renata Potrich 10 December 2018 (has links)
Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2019-03-27T00:17:29Z No. of bitstreams: 1 Flávia_Signor_2018.pdf: 1348843 bytes, checksum: 62c9ea99a98f3a9ffcf14e532dd3551b (MD5) / Made available in DSpace on 2019-03-27T00:17:29Z (GMT). No. of bitstreams: 1 Flávia_Signor_2018.pdf: 1348843 bytes, checksum: 62c9ea99a98f3a9ffcf14e532dd3551b (MD5) Previous issue date: 2018-12-10 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Estado do Paraná (FA) / The consumption preference for the tilapia meat by Brazilians is represented by fillet, being this the main product commercialized by the industries that benefit of the specie. In industry, the fillet production cost is high because of the low fish utilization, which in turn, it generates residues that can potentially be transformed into commercially viable by-products, such as mechanically separated meat (MSM). In this sense, this work aims to improve the nutritional quality of Nile tilapia MSM (Oreochromis niloticus) through the pressing process for the elaboration of new products with added value. The present study was divided in two stages: 1st stage - Study the effect of pressing process on the nutritional quality of the Nile tilapia MSM and the effect of the addition fish-based condiment on development of the MSM patties (article 1). The results showed that the pressing process improves the nutritional quality of the tilapia MSM and the addition fish-based condiment in the patties provides a better sensorial acceptance of the product. In the 2nd stage - Evaluates the effects of the addition of pregelatinized starch and dextrin in the preparation of MSM patties obtained from fillet waste from Nile tilapia (Article 2). The results demonstrated that the addition of pregelatinized starch and dextrin improves the texture of tilapia MSM patties, as well as their sensorial characteristics. Based on the data obtained, it can be concluded that the residues (carcass) generated in the process of fillet processing can be a viable alternative as raw material for the elaboration of new structured products, adding value and enabling the fish processing industry to increase profits. / A preferência do consumo da carne de tilápia pelos brasileiros é representada pelo filé, sendo este o principal produto comercializado pelas indústrias que beneficiam a espécie. O custo de produção de filé é elevado, em virtude do baixo aproveitamento do pescado, em contrapartida, gera resíduos que potencialmente podem ser transformados em subprodutos com aproveitamento mercadológico, como é o caso da carne mecanicamente separada (CMS). Nesse sentido, este trabalho teve por objetivo melhorar a qualidade nutricional da CMS de tilápia do Nilo (Oreochromis niloticus) através do processo de prensagem para a elaboração de novos produtos com valor agregado. O presente estudo foi dividido em duas etapas: 1º etapa - Estuda a influência do efeito da prensagem sobre a qualidade nutricional da CMS de tilápia do Nilo e o efeito da adição de condimentos a base de peixe no desenvolvimento de empanados com CMS (artigo 1). Os resultados demostraram que o processo de prensagem melhora a qualidade nutricional da CMS de tilápia e a adição de condimentos a base de peixe nos empanados proporciona uma melhor aceitação sensorial do produto. Na 2º etapa – Avaliou-se o efeito da adição de amido pré-gelatinizado e dextrina na preparação de empanados de CMS da carcaça de tilápia do Nilo (artigo 2). Os resultados demostraram que a adição de amido pré-gelatinizado e dextrina melhora a textura dos empanados de CMS de tilápia, assim como suas características sensoriais. Baseados nos dados obtidos pode-se concluir que o subproduto da filetagem de tilápia do Nilo (carcaça) gerados no processo de beneficiamento do filé são uma alternativa viável como matéria prima para a elaboração de novos produtos restruturados, agregando valor, e possibilitando a indústria de beneficiamento de pescado um incremento nos lucros.
83

Efeito das adições de boro na magnetostricção de ligas policristalinas dos sistemas Fe-Al e Fe-Ga / Effect of boron additions on the magnetostriction of polycrystalline alloys of the Fe-Al and Fe-Ga systems

Claudio Teodoro dos Santos 12 March 2013 (has links)
Os materiais magnetostrictivos apresentam deformação elástica quando são submetidos a um campo magnético ou mudança das propriedades magnéticas quando são submetidos a uma tensão mecânica, e por isso são de grande interesse para aplicações em atuadores, sensores e aproveitadores de energia. Entretanto, os melhores materiais magnetostrictivos disponíveis são caros e frágeis. Nos últimos anos foi descoberta uma nova classe de materiais magnetostrictivos que superam este problema, a classe das ligas Fe-Ga e Fe-Al, que possuem a rara combinação de moderada magnetostricção, boas propriedades mecânicas e baixo custo associado. Atualmente, as pesquisas têm buscado meios de melhorar a magnetostricção destas ligas, tanto por adições ternárias de outros átomos, como pela utilização de diferentes métodos de fabricação, tratamentos térmicos ou processamentos mecânicos. No presente trabalho foi avaliado o efeito das adições de B e do processo de solidificação rápida na magnetostricção e microestrutura das ligas Fe-Al e Fe-Ga. Para isso, ligas policristalinas de composição nominal (Fe80Al20)1-0,01yBy, (Fe80Ga20)1-0,01yBy e (Fe72Ga28)1-0,01yBy, com y = 0; 0,5; 1; 1,5 e 2% at., foram produzidas por fusão a arco e pela técnica de solidificação rápida \"splat cooling\". A caracterização microestrutural das amostras foi realizada no MEV/EDS e DRX. A magnetostricção foi medida com campo magnético de 0 a ±2 T em 4,2, 77 e 300 K, por dilatometria de capacitância. As adições de B ocasionaram a precipitação de Fe2B nos contornos de grão da fase A2 e/ou D03 das ligas Fe-Al e Fe-Ga, resultando na redução do tamanho de grão e formação de cristais dendríticos. As ligas Fe80Al20 apresentaram um valor máximo de magnetostricção de 74 ppm com a adição de 2% at. de B. Já as ligas Fe80Ga20 e Fe72Ga28 apresentaram um máximo com a adição de 1% at. de B, sendo de 81 ppm e 143 ppm, respectivamente. Conclui-se que estas adições de B tiveram um efeito benéfico na magnetostricção das ligas Fe-Al e Fe-Ga como-solidificadas, uma vez que chegaram a ocasionar um aumento de até 100% desta propriedade em relação à liga sem B. Por outro lado, a solidificação rápida não teve efeito sobre a magnetostricção das ligas Fe-Al-B. / Magnetostrictive materials exhibit elastic deformation when subjected to a magnetic field or changing in magnetic properties when subjected to mechanical stress, so they are of great interest for applications in actuators, sensors and energy harvesters. However, the best available magnetostrictive materials are expensive and fragile. In the last years has been discovered a new class of magnetostrictive material which overcome this problem, the class of the Fe-Ga and Fe-Al alloys, which have the unusual combination of moderate magnetostriction, good mechanical properties and low associated cost. Currently, research has searched ways to improve the magnetostriction of these alloys, both for ternary additions of other atoms or by using different methods of preparation, heat treatment or mechanical processing. In the present study, we evaluated the effect of B additions and rapid solidification process on the microstructure and magnetostriction of Fe- Al and Fe-Ga alloys. For this purpose, polycrystalline alloys of nominal composition (Fe80Al20)1-0.01yBy, (Fe80Ga20)1-0.01yBy and (Fe72Ga28)1-0.01yBy, with y = 0, 0.5, 1, 1.5 e 2 at.% were produced by arc melting and splat cooling rapid solidification technique. Microstructural characterization of the samples was performed by SEM/EDS and XRD. The magnetostriction was measured under magnetic field of 0 to ±2 T, at 4.2, 77 and 300 K, by capacitance dilatometry. The B additions caused precipitation of Fe2B at the grain boundaries of A2 and/or D03 phase of Fe-Al and Fe-Ga alloys, resulting in a reduction of the grain size and formation of dendritic crystals. The Fe80Al20 alloys showed a maximum magnetostriction of 74 ppm with the addition of 2 at.% B. And, the Fe80Ga20 and Fe72Ga28 alloys showed a peak with the addition of 1 at.% B, of 81 ppm and 143 ppm, respectively. We concluded that these B additions had a beneficial effect on the magnetostriction of Fe- Al and Fe-Ga as-cast alloys, since they caused an increase up to 100% of this property in relation to the alloy without B. On the other hand, the rapid solidification had no the same effect on the magnetostriction of Fe-Al-B alloys.
84

Chiral aldimines in diastereoselective carbon nucleophile additions

Dema, Haythem Karim 27 July 2012 (has links)
No description available.
85

Indolizidine alkaloids and asymmetric synthesis of carbocycles

Wingert, David Alexander Unknown Date
No description available.
86

The magnetic and magnetoelastic properies of meld-spun MbFe2 based alloys and their temperature dependencies

Jerems, Frank January 1999 (has links)
No description available.
87

The effect of fluorine substituents in conjugated polymers

Lӧvenich, Peter Wilfried January 2001 (has links)
A new route to a well-defined block copolymer with alternating PEO-solubilising groups and fluorinated distyrylbenzene units was established. The Horner Wittig reaction was used as the polycondensation reaction. The non-fluorinated analogue of this block copolymer was prepared via the Wittig reaction. Both polymers were soluble in chloroform and free-standing films could be cast from solution. The position of the HOMO and LUMO energy levels of these two materials were determined by a combination of cyclic voltammetry, UV photoelectron spectroscopy and UV/Vis absorption spectroscopy. The presence of fluorine substituents on the distyrylbenzene unit had no influence on the HOMO-LUMO band-gap (3.0 eV). However, the position of these two energy levels relative to the vacuum level was shifted to higher energies (0.85 eV shift) in the case of the fluorinated block copolymer. The photoluminescence quantum efficiency of the fluorinated block copolymer was 17%, that of the non-fluorinated block copolymer was 34%. The former was used as the electron conducting layer in a light emitting diode with poly(p-phenylene vinylene) as the emissive layer. The latter was used as the emissive layer in light emitting diodes. Luminances over 2000 cd/m(^2) were observed for devices based on the non-fluorinated block copolymer using indium tin oxide as the anode and aluminium as the cathode. The luminescence efficiency of such devices was as high as 0.5 cd/A, corresponding to an internal quantum efficiency of 1.1%.Furthermore, an oligo(p-phenylene vinylene) was synthesised that contained two terminal fluorinated benzene rings and two central non-fluorinated benzene rings, all connected by vinylene bridges. This material aggregated in a 'brickwall' motif, where each molecule overlaps with two halves of molecules in the row above and below. The structure of this J aggregate is due to aryl-fluoroaryl-interactions and was demonstrated by X-ray crystal structure analysis.
88

Approche performantielle des bétons : vers une meilleure caractérisation des indicateurs de durabilité / Approach of performance based durability : towards a better characterization of sustainability indicators

Allahyari, Ilgar 20 May 2016 (has links)
La fabrication du ciment, par sa phase de clinkérisation, est très énergivore et émet une quantité importante de gaz à effet de serre dans l'atmosphère. En effet, la production d'une tonne de clinker génère environ une tonne de CO2. Afin de réduire ces émissions, une des alternatives est l'utilisation des additions minérales dans la confection des bétons en remplacement partiel du ciment. Cette substitution apparait comme une des solutions les plus efficaces permettant à la fois de diminuer l'énergie consommée et de réduire le dégagement de CO2 dans l'atmosphère. Cette étude s'inscrit dans un projet plus global de développement des bétons de bâtiment à matrices binaires (ciment + additions) s'appuyant sur des critères de propriétés de transfert. En effet, afin de répondre à certaines exigences de durabilité, une campagne expérimentale a été menée sur des bétons confectionnés selon la norme européenne NF EN 206 qui autorise deux méthodes de formulation : * l'approche dite prescriptive, qui porte sur des obligations de moyens, * l'approche dite performantielle, qui consiste à fixer des exigences en terme de performances basées sur des indicateurs généraux ou spécifiques de durabilité. Ce travail de recherche a donc consisté à comparer les propriétés physico-chimiques de bétons à forte teneur en addition minérale (filler calcaire, cendre volante, laitier de haut fourneau et métakaolin), dérogeant à l'approche prescriptive avec celles des bétons de référence répondant à cette même norme. Cette comparaison s'est effectuée au travers d'indicateurs de durabilité généraux (porosité accessible à l'eau, perméabilité à l'oxygène, coefficient de migration des ions chlorure et teneur en Ca(OH)2) et d'indicateurs spécifiques : la résistance à la carbonatation naturelle et accélérée. D'un point de vue méthodologique, les travaux réalisés dans le cadre de cette recherche ont montré l'intérêt de l'approche performantielle pour la formulation des bétons. Mais, à l'heure actuelle, les outils disponibles, c'est à dire les indicateurs généraux et spécifiques, ne sont pas suffisants pour répondre à l'ensemble des bétons couvrant ce texte normatif. A l'échelle du matériau (béton pour une application en bâtiment), les campagnes expérimentales menées ont montré que dans la majorité des cas, les bétons à forte teneur en addition minérale (dérogeant aux spécifications) présentent des comportements proches de ceux observés sur les bétons de référence (répondant à l'approche prescriptive). / The manufacturing of cement, by its clinkering process, is very energy-consuming and emits an important quantity of greenhouse gases in the atmosphere (1 ton of clinker produced 1 ton of CO2 released into the atmosphere). To maximize this latter from an environmental point of view, it is necessary to reduce the cement content. This can be done by replacing part of the cement with mineral additives during the manufacturing phase. This substitution seems one of the most effective solutions allowing, at the same time, to decrease the energy consumed and to reduce the release of CO2 into the atmosphere. This study is part of a more comprehensive development project of concrete building binary matrices (cement + mineral additives) based on transfer properties criteria. Indeed, in order to answer certain sustainability requirements, an experimental campaign was conducted on concrete, made according to the new European standard (EN 206) that allows two methods of formulation: * a traditional prescriptive approach, based on limiting values for the composition (minimum binder content, maximum water to binder ratio, compressive strength class...) of concrete exposed to some aggressive environmental conditions, * an innovative method based on a performance approach for concrete properties. The present work aims at studying the physico-chemical properties of cementitious materials with high substitution rates of cement by mineral additions (limestone filler, fly ash, slag, metakaolin) derogating from the prescriptive approach with reference to concrete corresponding to the same standard. This comparison was made with general durability indicators (water porosity, oxygen permeability, chloride migration coefficient and portlandite content) and specific durability indicators: carbonation in natural and accelerated conditions. From a methodological point of view, the research carried out in the framework of this project has shown the interest of the performance-based approach with regards to the concrete formulation. But at the moment, the available tools, namely the general and specific indicators, are not sufficient to respond to all these types of concrete. However, considering the performance, economic and environmental criteria, laboratory results showed that concrete made according to a performance-based approach had a performance close to reference concrete and the standard prescription could still be reassessed.
89

Optimisation des propriétés des bétons projetés par voie sèche / Optimisation of dry-mix shotcrete properties

Armengaud, Julie 09 December 2016 (has links)
Le béton projeté est une méthode de mise en place consistant en la projection pneumatique de béton sur une surface à grande vitesse. Dans le cas de la méthode par voie sèche, le mélange granulats-ciment est introduit sec en machine, l'eau est ajoutée à la fin du transfert. Cette technique, très employée, est néanmoins génératrice de pertes importantes par rebond, pouvant s'élever jusqu'à 40% de la masse projetée. L'enjeu de la réduction des pertes est à la fois économique et environnemental. Les facteurs influents sur le rebond sont liés aux techniques de projection et à la formulation. Ce travail de thèse a pour objectif l'optimisation de la formulation du béton afin de réduire les pertes par rebond, mais également d'améliorer la durabilité. L'étude porte en particulier sur l'influence sur le rebond : du squelette granulaire, de la teneur en eau et de l'emploi d'additifs et/ou d'additions de substitution. Une approche modélisation du phénomène de rebond est également abordée. / Sprayed concrete is a concrete pneumatically projected onto a surface at high velocity. Dry-mix shotcrete is a process in which dry constituents are introduced into the machine and conveyed through a hose to the nozzle, where the water is added. This process is used in various civil engineering or construction projects; unfortunately, it can lead to high losses of concrete due to rebound (up to 40% of the total mass of material). Such losses induce overconsumption of material, which is damaging for the cost of the work and for the environment. Rebound depends on technicals parameters and mix design. The present work focuses on rebound reduction and also on durability enhancement by modification of the mix design. The influence of aggregate size distribution, water content and supplementary cimentitious material is studied. An analytical approach of rebound phenomenon is also implemented.
90

Estudo da durabilidade de argamassas utilizando cinzas e casca de arroz. / Study of the durability of mortars using ash and husk of rice.

SOUZA, Jozilene de. 05 October 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-10-05T14:15:18Z No. of bitstreams: 1 JOZILENE DE SOUZA - TESE (PPGEP) 2008.pdf: 3086749 bytes, checksum: d738b230b5a0dcf70a631cd0699b9989 (MD5) / Made available in DSpace on 2018-10-05T14:15:18Z (GMT). No. of bitstreams: 1 JOZILENE DE SOUZA - TESE (PPGEP) 2008.pdf: 3086749 bytes, checksum: d738b230b5a0dcf70a631cd0699b9989 (MD5) Previous issue date: 2008-12-19 / O Brasil está, atualmente, entre os maiores produtores de grãos do mundo, em especial o arroz. Com o beneficiamento deste produto são geradas grandes quantidades de resíduos (casca) que ocasionam problemas ambientais, pela deposição inadequada no meio ambiente e por seu longo tempo de degradação. A incorporação destes resíduos industriais a componentes para construção civil, como concretos e argamassas, é uma das possíveis soluções para o aproveitamento de subprodutos poluentes estando em acordo com os princípios da sustentabilidade. Este trabalho tem como objetivo estudar a durabilidade de argamassas convencionais e alternativas incorporadas com resíduos de cinza da casca de arroz substituindo parte do aglomerante e casca de arroz substituindo o agregado miúdo, através do envelhecimento acelerado, por ciclos de molhagem e secagem. Inicialmente foi realizada com as matérias-primas convencionais e alternativas uma caracterização física, química e mineralógica através dos seguintes ensaios: análise granulométrica por peneiramento e difratometria a laser, área especifica, massa unitária, análise química, difração de raios X, análise térmica diferencial e gravimétrica. Para avaliar a durabilidade pelo método do envelhecimento acelerado, por ciclos de molhagem e secagem, foram confeccionados corpos-deprova de argamassas convencionais e argamassas alternativas nos traços 1:4; 1:6 e 1:8 incorporando 3%, 6%, 9%, 15%, 20% e 30% de resíduo de cinza de casca de arroz em substituição ao aglomerante e 10%, 20% e 30% de casca de arroz em substituição ao agregado miúdo por períodos de cura de 28, 63, 91, 180 e 360 dias. As propriedades físico-mecânicas determinadas foram: absorção de água, densidade aparente e resistência. Os resultados dos ensaios de caracterização das matérias-primas convencionais (cimento e agregado miúdo) e alternativos (cinza e casca de arroz) encontram-se dentro dos padrões estabelecidos pelas normas da ABNT, indicando superfície específica e índice de finura da cinza de casca de arroz bem superior a do cimento empregado. Os resultados evidenciaram que a cinza de casca de arroz é predominantemente amorfa e tem alta pozolanicidade de acordo com as especificações da ABNT, possibilitando seu uso em concretos e argamassas pelas suas características de grande finura. Em relação ao comportamento mecânico, foram encontrados valores superiores dos corpos-de-prova alternativos incorporados com cinza de casca de arroz em relação aos convencionais mesmo quando expostos ao envelhecimento acelerado, enquanto os corpos-de-prova das argamassas incorporados com casca de arroz apresentaram valores dentro das especificações da ABNT e inferiores aos convencionais, comprovando a viabilidade técnica da utilização destes resíduos,uma vez que não se evidenciou influência na durabilidade, além de ser uma medida ecologicamente correta. / Brazil is one of the greatest producers of grain in the world, especially in rice. With the industrialization of this product great amount of waste (husk) is generate and cause environmental problems, by the inadequate discharge in the environment and by the long time to deteriorate. The incorporation of this industrial residue as components to civil construction, as concrete and mortars, is one of the possible solutions to use this pollutants sub products and this is in agreement with the sustainable principle. The aim of this work is to study the durability of the conventional and alternative mortars incorporated with husk rice ash residue by substituting part of the agglomerate and rice husk substituting small aggregate. The durability was study by the accelerate weathering (by wetting and drying cycles). Firstly it was done a physical, chemical and mineralogical characterization of the conventional and alternatives raw materials by the following techniques: particle size by sieving and laser diffraction, surface area, specific mass, chemical analysis, X-rays diffraction, differential thermal analysis and gravimetry. The pozzolanic activity was measured according to the BNT NBR 12653(1997) norm. To evaluate the durability by the accelerate weathering (wetting and drying cycles) it was made body sample with conventional and alternative mortars with traces of 1:4; 1:6 e 1:8 incorporated with 3%, 6%, 9%,15%, 20% and 30% of ash rice husk residue in substitution of agglomerate and 10%, 20% and 30% of rice husk in substitution to small aggregate, for cure period of 28, 63, 91, 180 and 360 days. The physical and mechanical properties were: water absorption, apparent density,mechanical resistance and mass loss. The results of the conventional (cement and small aggregate) and alternative (ash and husk rice) raw materials characterization are in the standard values established by ABNT norms, indicating surface area and amount of fine particles of the husk rice ash are superior to the cement used. The results put in evidence that the husk rice ash is predominantly amorphous and has high pozzolanicity according to the specifications of the ABNT. This makes possible the use of this ash in concrete and mortars due to the great amount of fine particles. In relation to the mechanical properties, the results shown values superior to the body samples incorporated with husk rice in relation to the conventional even when exposed to the accelerate weathering. To the body samples incorporated with husk rice presented values according to the ABNT specifications and inferior to the conventional ones. It was concluded that the use of these residues are technical viable once did not present influence in the durability and also is an ecological correct action.

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