Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-09-30T14:02:28Z No. of bitstreams: 1 Dissertação - Claudionildo Teles Batalha.pdf: 5805065 bytes, checksum: 3edbb62a9308274ff4069328e815f8e8 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-02T20:08:35Z (GMT) No. of bitstreams: 1 Dissertação - Claudionildo Teles Batalha.pdf: 5805065 bytes, checksum: 3edbb62a9308274ff4069328e815f8e8 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-02T20:40:37Z (GMT) No. of bitstreams: 1 Dissertação - Claudionildo Teles Batalha.pdf: 5805065 bytes, checksum: 3edbb62a9308274ff4069328e815f8e8 (MD5) / Made available in DSpace on 2015-10-02T20:42:01Z (GMT). No. of bitstreams: 1 Dissertação - Claudionildo Teles Batalha.pdf: 5805065 bytes, checksum: 3edbb62a9308274ff4069328e815f8e8 (MD5) Previous issue date: 2012-03-02 / OUTRAS / In this research study was conducted on the production of Portland cement mortar with the use of ash sludge from water treatment plant in the city of Manaus in the partial replacement of Portland cement. The sludge ash obtained after the process of drying, grinding and calcination temperature of 650 ° C, was used as a component in the mixture, partially replacing cement by 5%, 10% and 15% by weight. Tests were performed to obtain the physical and mechanical properties of the cementitious matrix, the influence of ash WTS (CLETO) in the array, testing X-ray diffraction, thermal analysis, axial compressive strength, modulus of elasticity and absorption porosimetry. The results show that the use of CLETO and technically feasible: the compressive strength of mortar with a content of 5% and 15% ash replacing the cement had, at 28 days, statistically equal results compared to the reference mortar. The porosimetry test showed that the ash as well as providing a reduction in consumption of cement in the mix, had worked on refining the pore structure of mortar with 5% CLETO, reducing 15,64% increase in the macropores and mesopores 4% compared to the reference mortar. In capillary absorption test, the mortars had lower rates compared to the reference mortar, confirming the effect of fillers in the matrix CLETO. / Nesta pesquisa foi efetuado estudo sobre a produção de argamassa de cimento Portland com a utilização da cinza do lodo da estação de tratamento de água da cidade de Manaus em substituição parcial ao cimento Portland. A cinza do lodo, obtida após os processos de secagem, moagem e calcinação na temperatura de 650 °C, foi usada como componente da mistura substituindo parcialmente o cimento em 5%, 10% e 15% em massa. Foram efetuados ensaios para obtenção das propriedades físicas e mecânicas da matriz cimentícia, influência da cinza de lodo de ETA (CLETA) na matriz, ensaios de difração de raios X, análise térmica, resistência à compressão axial, módulo de elasticidade, porosimetria e absorção. Os resultados apresentados mostram que o uso da CLETA é viável técnicamente: as resistências à compressão das argamassas com teor de 5% e 15% de cinza substituindo o cimento apresentaram, aos 28 dias, resultados estatísticamente iguais em comparação à argamassa de referência. O ensaio de porosimetria mostrou que a cinza além de proporcionar redução no consumo de cimento na mistura, atuou no refinamento da estrutura de poros da argamassa com 5% de CLETA, reduzindo 15,64% os macroporos e aumento em 4% os mesoporos em relação à argamassa de referência. No ensaio de absorção por capilaridade, as argamassas apresentaram taxas menores em relação à argamassa de referência, comprovando o efeito fíler da CLETA na matriz.

Atualmente o maior impacto ambiental do concreto como material de construção origina-se das emissões de CO2 durante a produção do cimento. Uma das alternativas atualmente utilizadas para minimizar este impacto, é a utilização de adições minerais como substituição ao cimento. Entre as diferentes adições utilizadas, o uso de fíler calcário parece ser uma alternativa interessante para melhorar a sustentabilidade do uso do concreto na construção. Consequentemente, o presente estudo foca a análise do impacto da substituição do cimento por fílers de origem calcária (dolomita) no comportamento do concreto em estado fresco e endurecido, especialmente focando-se numa avaliação reológica e na retração por secagem do material. Para tal fim, foram formulados três microconcretos com teores de fíler calcário de 80%, 60% e 20% em relação ao peso dos finos totais (cimento mais fíler calcário). O teor de finos totais e de água foram mantidos constantes para todas as formulações resultando em misturas com similar volume de pasta. O comportamento reológico das misturas foi avaliado num reômetro de movimento planetário. Foram moldados corpos de prova para caracterização mecânica e acompanhamento da retração por secagem. A porosidade das pastas também foi avaliada usando a porosimetria por intrusão de mercúrio. As propriedades reológicas como a tensão de escoamento e a viscosidade foram influenciadas pelo teor de substituição de cimento por fílers. Maiores volumes de fílers na pasta produziram menores tensões de escoamento e, por consequência, maiores valores de abatimento foram obtidos. No entanto, a viscosidade plástica aumentou com teor de fílers. No estado endurecido, a maior substituição de cimento por fílers diminui a intensidade da retração por secagem devido ao menor teor de cimento na pasta e a modificações na estrutura porosa do material. Os resultados experimentais da retração foram comparados com os valores obtidos pelos modelos de previsão da retração: ACI 209, CEB-FIP, B3 e GL2000. Observou-se que os modelos superestimam os valores da retração conforme aumenta a substituição de cimento por fílers na pasta. Portanto, esses modelos devem ser calibrados considerando outros fatores, tais como: a quantidade de fíler utilizado em substituição de cimento. Esta consideração poderia otimizar o uso dos modelos em fase de projeto para verificar se os valores da retração esperados estão dentro dos limites normalmente aceitos. / Currently the biggest environmental impact of concrete as a building material originates in CO2 emissions during the production of cement. For this reason, one of the alternatives currently used to reduce these emissions is the use of mineral additions as cement replacement. Among the different additions used, the use of limestone fillers to replace cement appears to be an interesting alternative for improve the sustainability of the concrete used in construction. Consequently, this study focuses on the analysis of the impact of the replacement of cement by limestone fillers in fresh and hardened concrete, especially focusing on rheological behavior and shrinkage of the material. To this end, three microconcretos were formulated with fillers limestone content of 80%, 60% and 20% by weight relative to the total fine (limestone fillers and cement). The total content of fine and water were held constant for all formulations resulted in mixtures with similar volume of paste. The rheological behavior of the mixes was evaluated in a planetary motion rheometer. For mechanical characterization and measurement of shrinkage, specimens were molded. The porosity of the pastes was also evaluated using mercury intrusion porosimetry. The rheological properties such as yield stress and viscosity were influenced by the amount of cement that was replaced by fillers. Further filers volumes in the pulp produced smaller flow stress and, consequently, higher allowance values were obtained. Larger volumes of filler in the paste produced lower yield stresses and, consequently, higher slump values were obtained. However, the plastic viscosity increased with filers content. In the hardened condition, the largest cement replacement by limestone fillers reduced the intensity of shrinkage due to the lower content of cement paste and changes in the porous structure of the material. The experimental results of shrinkage were compared with the values obtained by shrinkage prediction models: ACI 209, CEB-FIP, B3 and GL2000. It was observed that the models overestimate the shrinkage values with increasing cement replacement by limestone fillers. Therefore, these models must be calibrated considering other factors such as the amount of fillers used as cement replacement This consideration would optimize the use of these models in the design phase to verify that the values of the expected shrinkage are within the limits normally accepted.

Les ciments acryliques osseux sont une solution courante pour traiter des lacunes osseuses. L'incorporation de charges permet d'en améliorer les propriétés, ainsi l'amidon pour la dégradabilité, associé à l’acétate de cellulose pour les propriétés mécaniques, et les phosphocalciques pour ces dernières et la bioactivité. Très souvent, le polymère est le polyméthacrylate de méthyle et l'amidon, celui issu du maïs. La majorité des études les concernent. Celle-ci porte donc sur des formulations classiques mais à base de 2-hydroxyéthylméthacrylate, incorporant un amidon de waxy-maïs, maïs, amylomaïs, blé, pois ou pomme de terre, avec ou sans enzyme (α-amylase). L’HEMA apporte sa capacité à s’hydrater et les amidons à se dégrader. Temps et température maximale de prise ont été étudiés en fonction de la formulation, de même, le taux d'hydratation du ciment et sa perte de masse en fonction du temps d'immersion dans un fluide biologique. Les propriétés mécaniques ont été approchées à travers des essais de traction et de compression. La radio-opacité a été prise en compte. Paramètres de prise et taux d'hydratation (d'où un gonflement in situ favorable au comblement d'une lacune) se sont révélés peu influencés par l’origine botanique de l'amidon ou la présence de l'enzyme, contrairement à la dégradabilité. Le gonflement, néfaste si trop important, a été contrôlé grâce à une pré-saturation en eau, la perte des propriétés mécaniques après immersion en découlant l'étant par ajout de plâtre. Le dioxyde de zirconium s’est révélé le radio-opacifiant le plus approprié. L’ensemble des résultats a conduit à formuler deux ciments optimisés en fonction de la dégradabilité recherchée. / Acrylic cements are a current solution to deal with osseous gaps. The incorporation of fillers allows improving the properties, so starch for the degradability, associated with cellulose acetate for the mechanical properties, and calcium phosphates for the latter and the bioactivity. Very often, the polymer is polymethyl methacrylate and the starch is issued from corn. So the majority of the studies concern them. Thus this one concerns classic formulations but with 2-hydroxyethylmethacrylate, incorporating starch from waxy-maïs, corn, amylomais, wheat, pea or potato, with or without enzyme (α - amylase). HEMA brings its capacity to hydrate and starches to degrade. Setting time and maximal temperature were studied according to the formulation, also, the water uptake of the cement and its weight loss according to the immersion time in a biological fluid. The mechanical properties were approached through tensile and compression tests. The radio-opacity was taken into account. Curing parameters and water uptake (leading to in situ swelling favourable to the filling of a gap) were little influenced by the botanical origin of starch or by the presence of enzyme, contrary to the degradability. The swelling, negative if too important, was monitored through a pre-saturation by water and the resulting loss of the mechanical properties after immersion through addition of plaster. The zirconia was the most appropriate radio-opacifier. The results led to formulate two cements optimized according to the desired degradability.

The job interview is a gatekeeping encounter and it is crucial that the recruitment process is conducted in a fair and just way. Potential gendered verbal behaviour might affect an interviewer's impression and judgement of the interviewee. Previous research has shown that men and women differ in several ways in verbal communication, both as regards formal and informal encounters. In the present paper, a corpus study on forty job interviews is conducted with the aim to find out whether there are any differences between men and women when it comes to turn-length and the use of boosters, hedges, fillers and pauses. The results show that in the majority of the features under scrutiny, there is no statistically significant difference. These results do not go in line with earlier research on gendered verbal behaviour. Proposed explanations for these results are that the female interviewer might have encouraged a less typically gendered verbal behaviour and that younger generations have developed a less gendered conversational style compared to older generations. However, due to the limitations of the present study, no empirical conclusion can be drawn regarding this and further research needs to be conducted in order to fully explain these research findings.

Dans un contexte de développement durable, des matériaux thermoplastiques multiphasés biosourcés issus de dimères d’acides gras ont été élaborés pour développer une « eco-membrane » durable pour le bâtiment. Différentes formulations intégrant des polymères thermoplastiques biosourcés, polyuréthane thermoplastique (TPU) et polyamide (DAPA), des micro-charges minérales et des renforts cellulosiques ont été élaborées et analysées. Les relations « structures-propriétés » de ces systèmes multiphasés ont été étudiées. Les architectures macromoléculaires proches ont permis d’obtenir un certain degré de compatibilité entre les polymères. Les viscosités à l’état fondu du TPU et DAPA sont comparables, ce qui permet une bonne dispersion des phases du mélange lors de la mise en œuvre. Les propriétés mécaniques et la stabilité dimensionnelle des mélanges sont améliorées par ajout de micro-charges minérales. L’impact du facteur de forme des charges sur le module d’Young a été analysé et modélisé avec un modèle micro-mécanique. Des essais du type charge-décharge ont également été menés afin d’étudier le comportement à la fatigue des biocomposites. Enfin, les interactions et les affinités entre les renforts et polymères ont été approchées. Des modifications chimiques ont été développées à la surface des fibres afin de diminuer leurs caractères hydrophiles et d’améliorer la compatibilisation avec la matrice. L’impact de ces modifications sur l’interface fibres-matrice a ensuite été analysé. Les différentes études réalisées ont permis de sélectionner pas à pas les différents constituants de l’éco-membrane pour réaliser in fine un prototype prometteur. / In the context of sustainable development, renewable multiphase systems from thermoplastics based on dimers of fatty acids were prepared to develop a renewable waterproofing material for building applications. Formulations based on thermoplastics, i.e. thermoplastic polyurethane (TPU) and polyamide (DAPA), mineral micro-fillers and cellulosic fibers were prepared with a special focus on the morphology-property relationships of the multiphase systems obtained thereof. The close macromolecular architectures promote a certain degree of compatibility between the polymers. Comparable viscosities in the melt state ensure a good dispersion of the matrices within each other during processing. The mechanical properties and dimensional stability were improved with micro-fillers. The effect of the aspect ratio of the fillers on the elastic properties was investigated and micro-mechanical modelling of the Young’s Modulus was performed. The fatigue behavior of the biocomposites was also examined through loading and unloading tests. Finally, interactions and affinities between the fibers and polymers were characterized. Chemical modifications were carried out on the surface of the fibers to decrease their hydrophilic nature and improve the fiber-matrix adhesion. The effect of the chemical modification was then investigated. Step-by-step, the studies carried out ensured the selection of the optimal components for a renewable waterproofing material enabling the production of a promising prototype.

Le PTFE ne peut pas être mis en forme par les procédés classiquement employés pour les polymères. La production de pièce peut se faire par compaction de poudre et frittage. Des charges peuvent être ajoutées à la poudre vierge. Afin de prédire les propriétés de la pièce à vert et d'avoir un outil fiable pour optimiser les paramètres du procédé de compaction, une modélisation du comportement mécanique de poudres de PTFE chargées, ou non, à température ambiante lors du pressage industriel est proposée. La caractérisation expérimentale des matériaux est réalisée grâce à un outil de compaction 3D installé dans la machine triaxiale ASTREE. A partir de ces essais originaux, un modèle Drucker-Prager/cap est identifié. Les variations importantes de densités et de propriétés sont décrites. Le changement de phase cristalline, prenant place à température ambiante et sous pression est également caractérisé, modélisé et implémenté dans le code EF. Ensuite, l'interaction entre le PTFE et l'outil métallique est vue comme un frottement interne entre le film de transfert de PTFE et le reste de la pièce. Elle est modélisée à partir des paramètres déjà identifiés, à savoir le coefficient de frottement interne du Drucker-Prager et la cohésion. Deux tests sont mis en place pour valider le modèle: un outil ¿dométrique instrumenté et un outil original " en V " offrant la possibilité de mesurer le champ de déplacement par Corrélation d'Image Numérique. Des simulations EF de l'ensemble du procédé sont finalement effectuées et comparées aux données industrielles. Les premiers liens entre les étapes de compaction et de frittage sont établis par caractérisation de la texture cristalline par DRX. / PTFE is not melt-processible. One of the production methods of PTFE parts consists in the powder compaction at room temperature followed by a thermal treatment, the sintering. Fillers can be added to the virgin powder. In order to be able to predict the properties of the obtained green parts and to have a reliable tool to optimize the parameters of the process, modeling of the mechanical behavior of PTFE compounds during their industrial pressing in big billets is proposed. Experimental characterization is made thanks to a 3D compaction tool, installed in the triaxial machine ASTREE. From original and complex loadings, a Drucker-Prager/cap model is identified, where the variations of density and properties are described. In addition to the elastoplastic model, a phase transformation in the crystalline structure at ambient temperature under pressure is experimentally characterized, modeled and implemented in the FE code. Then the interaction of the PTFE with a metallic counterpart is described as a friction between the PTFE transfer film and the bulk PTFE, characterized by the internal friction coefficient of the Drucker-Prager line once the cohesion of the material is reached. No additional parameter needs to be identified. Two laboratory tests allow the validation of the model, an instrumented œdometric tool and an original ‘V’ tool where the displacement field of the material during the compaction is measured by Digital Image Correlation. FE simulation of the whole compaction process is finally made and compared to industrial data. First links between the compaction and the sintering are established by a characterization of the crystalline texture thanks to XRD.

Ce travail porte sur l’étude des composites à base de polypropylène et de farine de bois. Seuls des composites à base d’une matrice polypropylène et de fibres végétales ont été mis en oeuvre sans aucun recours à quelque agent comptabilisant que ce soit. En premier lieu nous avons regardé l’influence de la viscosité initiale de la matrice polypropylène sur la processabilité des biocomposites en utilisant des polymères de grades variés. Puis nous avons étudié l’influence de la nature et de la concentration de la farine en utilisant des farines de pin (bois mou) et de chêne (bois dur). Enfin, une attention spécifique a été portée sur la possibilité de nucléation en phase Beta de la matrice polypropylène en présence de fibres végétales. Des polypropylènes β-Nucléés ainsi que des farines ayant subies des extractions par des solvants de leurs composés volatils ont été utilisées. Les mélanges obtenus ont été testés au moyen de la viscoélasticité à l’état fondu pour mettre en évidences les effets d’interaction charges-Matrices et par des mesures de diffraction aux rayons X ainsi que d’analyse thermique différentielle pour la caractérisation de leurs morphologies cristallines. / This doctoral thesis is focused on composites based on polypropylene and wood flour. Firstly, the experimental work deals with preparation of composites based on wood flour with various concentrations and isotactic polypropylene with various melt flow indexes. In terms of this study, one polypropylene, which can have also practical use, was chosen. Further, this polypropylene is investigated with various types and concentrations of wood flour. Also, the attention is devoted to the modification of polypropylene by a specific β-Nucleating agent. The differences are compared and described between the composites with neat and nucleated polypropylene. Further, the work is focused on solvent extraction of wood flour. The effect of extraction and solvent of wood flour is also examined in composites with neat and nucleated polypropylene. On prepared composites, the rheological, structural and thermal properties are studied. These properties differ depending on specific type of wood flour, its concentration and specific type of polypropylene. / Předložená doktorská práce je zaměřena na kompozity polypropylenu a dřevní moučky. V experimentální části práce jsou připraveny kompozity s různými koncentracemi plniva a izotaktických polypropylenů s různými indexy toku taveniny. Na základě této studie je vybrán jeden konkrétní polypropylen, který může mít v kombinaci s dřevní moučkou i praktické využití. Tento polypropylen je dále zkoumán s různými druhy a koncentracemi dřevní moučky. Pozornost je také kladena na úpravu vlastností izotaktického polypropylenu užitím specifického β-nukleačního činidla. Jsou porovnávány a popisovány rozdíly mezi kompozity s čistým a nukleovaným polypropylenem. Práce se dále zabývá extrakcí dřevní moučky v rozpouštědle. Je studován vliv extrakce a rozpouštědla dřevní moučky na vlastnosti připravených kompozitů. Byly studovány reologické, strukturální a tepelné vlastnosti, které se lišily v závislosti na zvoleném typu plniva, jeho koncentraci a typu polymerní matrice.

Cement penetrability is a key factor in multifilament cement composites. However, the modes of action and the concepts vary because of brittle and ductile fibers. In the case of brittle fibers such as glass, high penetrability of cement products in between the bundle filaments can lead to brittle composite behavior, and therefore addition in ductility is required. In order to have efficient bundle action and high bonding, fillers can be introduced in between the glass filaments, keeping the telescopic mode of failure but at the same time improving the bond and stress transfer within the filaments of the bundle, even at late ages, resulting in a ductile and high strength composite. On the other hand, ductile fibers such as polypropylene (PP), which also developing low bonding with the cement matrix, result in ductile cement composite but with relatively low strength. Therefore, in this case good penetrability of the cement in between the filaments of the bundle is essential in order to maximize the reinforcing efficiency of the bundle by improving bond. The penetrability of the matrix into a fabric structure and especially in between the bundle filaments made up the fabric is a result of fiber- matrix compatibility, which depends on: level of opening and spaces between the filaments, bundle surface properties including wetting and chemical affinity to the cement matrix, matrix viscosity, processing of the composite, and the nature of the fabric junctions and the resulting tightening effects of the bundle, i.e., influenced by the fabric structure itself.

The construction industry is closely tied to economic development economies, and increasing demand also presents a significant contribution to environmental degradation. The construction industry’s impact to climate change is led by the 8% contribution from the production of concrete mixtures, more specifically, the production of cement. The combination of using advanced mixdesign techniques (e.g., particle packing models -PPM) and more sustainable ingredients poses as a promising alternative to overcome concrete environmental impact. However, there is a lack of studies regarding the fresh state difficulties arising from the aforementioned combination. Therefore, this work appraises the use of mobility parameters to overcome the fresh state issue raised when mix-designing mortar mixtures through PPM and with high volume of limestone filler. Twelve mixtures were developed with distinct cement content ranging from 150 kg/m3 to 320 kg/m3. To produce sustainable mortar, besides using PPM, cement content was replaced by limestone filler. Time dependent fresh state analysis was performed using mortar slump flow and a rheological profile. In the hardened states, the compressive strength, porosity, surface electrical resistivity tests were performed. The main findings of the project observed a strong correlation between mobility parameters and five distinct rheological parameters: flow behaviour parameter, high shear rate viscosity and shear stress, low shear rate viscosity and shear stress. Additionally, in the hardened state, a dilution parameter IPScement was used to appraise the dilution and filler effect of the mortar mixtures. The works highlighted a promising method to produce eco-efficient mortars.

No description available.