Des composites polyamide-6 renforcés fibres de verre obtenus par injection réactive ont été caractérisés afin de remplacer ces fibres synthétiques par des fibres biosourcées de viscose haute ténacité. La première étape a été l’étude physico-chimique des fibres et de la matrice polymère thermoplastique par des techniques multiples : DSC, ATG, essais mécaniques, FTIR, RMN et mesure d’angle de contact. Afin d’améliorer l’interface entre la viscose haute ténacité et le polyamide-6, les fibres de viscose ont été fonctionnalisées en deux étapes. Premièrement, un traitement plasma oxygène a permis le nettoyage de la surface de ces fibres. Elles ont été ensuite fonctionnalisées par un agent de couplage silane. Une nouvelle méthode de dépôt de microgouttes de polymère sur les fibres a été développée, dans des conditions représentatives de l’injection réactive, afin de vérifier l’avantage d’un traitement de surface des fibres. Cette approche permet de déterminer la résistance au cisaillement interfacial entre les fibres et le polyamide-6, par déchaussement des microgouttes. Par la suite, des composites polyamide-6 renforcé viscose traitée ou non traitée ont été obtenus. / Polyamide-6 / glass fibers composites were studied in order to replace glass fibers with high tenacity viscose as a reinforcement, using a reactive injection process. The first step was the physico-chemical characterization of fibers and matrix using different techniques such as: DSC, TGA, mechanical testing, FTIR, NMR and contact angle measurements. In order to improve the interface between high tenacity viscose and polyamide-6, the viscose fibers were functionalized using a two step method. First, oxygen plasma was applied as a cleaning process to remove impurities. Secondly, the fibers were functionalized using an aminosilane. A new deposition technique of polymer microdroplets onto fibers, in conditions similar to these of reactive injection process, was developed in order to confirm the advantages of the silane treatment. Moreover, a pull-out test of these microdroplets led to the determination of the interfacial shear strength between polyamide-6 and high tenacity viscose fibers. Then, polyamide-6 composites reinforced with high tenacity viscose were obtained.

This master thesis summarizes the current knowledge regarding the design and properties of glass fiber reinforced concrete products. It also deals with the design of a new concrete recipe for Dako spol. s.r.o company. There is verified effect of changes in input materials in real conditions the company to increase tensile bending strength above 20 MPa.In particular, verification of the use of building chemistry like superplasticizing additives, polymer-cement matrix or a change type or dose of glass fiber.

Diploma thesis deals with study of properties of cementious composites with fiber reinforcement from glass and basalt inorganic fibers. Diploma thesis includes a theoretical and experimental part. The theoretical part deals with information about glass and basalt fibers, their durability and usage. In the experimental part we monitored properfies of cement composites with basalt and glass fibers. Fibers were exposed to an aggressive environment. The properties of composites with reference fibers were compared with composites with fibers affacted by the aggressive environment. The properties of composites were examined after 28 and 90 days. We monitored compresive strenght, bending tensile strenght, tensile strenght, surface layer strenght and SEM.

Diplomová práca sa zaoberá prípravou teromplastických kompzoitov s PMMA a PC matricou s potenciálnym využitím v automobilovom priemysle. Ako výstuž boli použité krátke sklenené, uhlíkové a PBO (poly(p-fenylén benzobisoxazol)) vlákna známe pod obchodným názvom Zylon®. Práve do PBO vlákien boli vkladané veľké nádeje vzhľadom na ich ohromujúce mechanické vlastnosti. Vplyv objemového zlomku vlákien na modulu pružnosti, pevnosť a ťažnosť kompozitov bol skúmaný. Experimentálne zistený modul pružností bol porovnaný so semi-empirickým Halpin-Tsai modelom. Prídavok sklenených a uhlíkových vlákien viedol k značnému zvýšeniu modulu pružnosti. Ukázalo sa, že po istej hodnote objemového zlomku dochádza k poklesu pevností kompozitov v dôsledku zvyšujúceho sa počtu defektov. Prídavok PBO vlákien preukázal len nepatrný vystužujúci efekt. Viskoelastické vlastností kompozitov boli skúmané pomocou dynamicko mechanickej analýzy (DMA). Termogravimetrická analýza (TGA), konfokálna laserová rastrovacia mikroskopia (CLSM) a rastrovacia elektrónová mikroskopia (SEM) boli využité k štúdiu štruktúry kompozitov.

This Master’s thesis deals with the lead-acid batteries, which are alternativ power supply. The lead-acid batteries are the oldest type of battery cells. This lead-acid batteries have a great use in hybrid electric vehicles (HEVs), which operate in different modes of vehicle operation. These modes correspond to the reactions taking place during discharging and charging the battery. The lead-acid batteries in hybrid electric vehicles work in mode PSoC. The practical part of the Master`s thesis examines how the characteristics of lead-acid batteries are modified due to admixture of glass fibers into negative active material and application of pressure to the electrode system.

[pt] A utilização de barras de polímero reforçado com fibra contínua (Fiber reinforced polymer, ou FRP) como reforço no concreto armado vem ganhando relevância no mercado devido às suas propriedades não corrosivas, alta resistência, durabilidade e transparência eletromagnética. Por outro lado, o comportamento frágil e o baixo módulo de elasticidade das barras de FRP limita sua aplicação e difusão no mercado da construção civil. Sob esta perspectiva, este trabalho avalia, em uma primeira etapa, o incremento de ductilidade em vigas de concreto armado com barras de GFRP (Glass fiber reinforced polymer) por meio da adição de fibras dispersas de vidro AR (álcali resistente) à matriz cimentícia e/ou pelo confinamento do concreto nas regiões críticas com o uso de estribos de GFRP. Para tal, são reportados e discutidos os resultados de ensaios realizados em oito vigas isostáticas sob flexão de quatro pontos, sendo quatro superarmadas e quatro são subarmadas. Em geral, as estratégias adotadas se mostraram bem-sucedidas apenas para as vigas superarmadas, que passaram a apresentar falhas caracterizadas por formação de cunha de compressão e grandes deslocamentos até a ruptura. Para avaliação da ductilidade, foram adotados dois métodos distintos: um baseado em energia (índice de ductilidade, (micro)E) e outro baseado em deformação (fator de performance, (micro)M). Para as vigas subarmadas, o fator de performance por meio da curvatura e o fator de performance por meio da deflexão representaram maiores incrementos de ductilidade para a viga com adição de fibras dispersas devido ao efeito do enrijecimento à tração, enquanto o índice de ductilidade não se mostrou uma boa alternativa para estas vigas. Para as vigas superarmadas, o fator de performance por meio da curvatura e o índice de ductilidade representaram maiores incrementos de ductilidade para as vigas com confinamento, enquanto no fator de performance por meio da deflexão, o incremento de ductilidade foi mais significativo para as vigas com adição de fibras. Em uma segunda etapa, é avaliada a capacidade de redistribuição de momentos fletores em três vigas hiperestáticas de dois vãos reforçadas com barras de GFRP contendo maior taxa de armadura inferior, bem como configurações distintas de armadura transversal e uso de fibras. Foi possível observar um aumento do momento nos centros dos vãos de 30 por cento e uma redução no momento no apoio central superior a 60 por cento, quando comparados aos momentos elásticos, que confirmam a influência da configuração da armadura na distribuição de esforços. / [en] The use of continuous fiber reinforced polymer (FRP) bars as an internal reinforcement for concrete has gained attention due to its non-corrosive properties, high resistance, requiring electromagnetic transparency. On the other hand, the brittle behavior and low modulus of elasticity of FRP bars limit their application and diffusion in the civil construction market. From this perspective, this work evaluates, firstly, the increase of ductility in GFRP (glass-fiber reinforced polymer) reinforced concrete beams by adding dispersed alkali-resistant (AR) glass fibers to the cementitious matrix and/or by confinement of the concrete in critical regions with the use of GFRP stirrups. To accomplish this task, the results of tests performed on eight statically determinate beams under four-point bending are reported and discussed, four of which are under-reinforced and four are over-reinforced. In general, the strategies adopted were successful only for the overreinforced beams, whose failures were characterized by the formation of a compression wedge and large displacements before rupture. For ductility evaluation, two distinct methods were adopted: one based on energy (ductility index, (micro)E) and another based on deformation (performance factor, (micro)M). For under-reinforced beams, the performance factor through curvature and the performance factor through deflection led to greater ductility increments for the beam with the addition of dispersed fibers due to the tensile stiffening effect, while the ductility index did not lead to good results. For the over-reinforced beams, the performance factor through curvature and the ductility index were able to describe the greater ductility increments for the confined beams, while the performance factor through deflection resulted in a greater ductility increment for the beams with discrete fiber addition. In a second step, the capacity of redistribution of moments in three statically indeterminate GFRP reinforced concrete beams with two spans and with a higher lower reinforcement ratio was evaluated for two different configurations of transverse reinforcement and for the use of fibers. It was possible to observe an increase in the positive moment of 30 percent (center of span) and a reduction in the negative moment (central support) greater than 60 percent, when compared to the elastic moments, confirming the influence of the reinforcement configuration on the distribution of internal forces.

Im Rahmen experimenteller Untersuchungen wurden Stahlbetonplatten hergestellt, mit verschiedenen textilen Bewehrungen verstärkt, mit 125 % Gebrauchslast vorgeschädigt und anschließend unter Gebrauchslast mit einer Brandbelastung nach der Einheitstemperaturkurve (ISO-834, Cellulosic curve) beaufschlagt. Alle Platten hielten der Brandbelastung bei gleichzeitiger Biegebeanspruchung mehr als 60 Minuten stand und zeigten weder Betonabplatzungen noch andere optische Schädigungen auf. Die für dieses überraschend positive Ergebnis verantwortlichen Mechanismen werden diskutiert, sind aber noch nicht vollständig verstanden. Eine Schlüsselrolle spielt dabei vermutlich das gute Rissverhalten von Textilbeton und interne Umlagerungen zwischen Textil und Stahlbewehrung.