Pultrusão é um de vários processos de fabricação de compósitos poliméricos. Seu princípio de funcionamento envolve a utilização de um conjunto de fibras de reforço, impregnadas previamente por uma resina polimérica termorrígida, que percorre o interior de uma matriz aquecida a fim curar a resina e dar o formato a um perfil sólido. Muitas variáveis de processo, tais como a temperatura das zonas de aquecimento sobre a matriz, a velocidade de tracionamento, a impregnação das fibras, a viscosidade da resina, entre outras, afetam a eficiência do processo assim como a qualidade e o desempenho dos compósitos. Neste estudo, foi investigada a influência do teor de fibra de vidro, do teor de carbonato de cálcio e da temperatura do reservatório de resina nas propriedades mecânicas, como a resistência à tração, o módulo de elasticidade, o alongamento até a ruptura e a dureza de barras sólidas circulares que foram fabricadas utilizando uma resina poliéster insaturada e um único peróxido orgânico. Foi constatado que o processo de pultrusão pode ser realizado utilizando um único iniciador de reação. Além disto, os resultados mostraram que a temperatura do reservatório de resina, o teor de carbonato de cálcio e o teor de fibra de vidro influenciaram de forma significativa nas propriedades das barras pultrudadas. Por fim, este estudo mostrou que é possível melhorar as características destes compósitos e, desta forma, desenvolver materiais que apresentem melhor qualidade e desempenho. / Pultrusion is one of several manufacturing processes of polymer composites. Its operating principle involves the use of a set of reinforcing fibers pre-impregnated with a thermoset resin which run through the interior of a heated die in order to cure the resin and to form a solid profile. Many processing variables such as die temperature, pulling speed, fiber impregnation, resin viscosity, among others, affect the process efficiency as well as the quality and performance of the pultruded composites. In this research, the influence of the glass fiber content, calcium carbonate content and the temperature of the resin bath on the mechanical properties, such as tensile strength, elastic modulus, elongation at break and superficial hardness of solid rods made with an unsaturated polyester resin and a single organic peroxide were investigated. It was observed that pultrusion process can be carried out using a single reaction initiator. In addition, the results showed that the temperature of the resin bath, the calcium carbonate and the glass fiber content have influenced significantly in the properties of the solid rods. Finally, this study showed that it is possible to improve the characteristics of such composites and, therefore, to develop materials that have good quality and performance.

Pultrusão é um de vários processos de fabricação de compósitos poliméricos. Seu princípio de funcionamento envolve a utilização de um conjunto de fibras de reforço, impregnadas previamente por uma resina polimérica termorrígida, que percorre o interior de uma matriz aquecida a fim curar a resina e dar o formato a um perfil sólido. Muitas variáveis de processo, tais como a temperatura das zonas de aquecimento sobre a matriz, a velocidade de tracionamento, a impregnação das fibras, a viscosidade da resina, entre outras, afetam a eficiência do processo assim como a qualidade e o desempenho dos compósitos. Neste estudo, foi investigada a influência do teor de fibra de vidro, do teor de carbonato de cálcio e da temperatura do reservatório de resina nas propriedades mecânicas, como a resistência à tração, o módulo de elasticidade, o alongamento até a ruptura e a dureza de barras sólidas circulares que foram fabricadas utilizando uma resina poliéster insaturada e um único peróxido orgânico. Foi constatado que o processo de pultrusão pode ser realizado utilizando um único iniciador de reação. Além disto, os resultados mostraram que a temperatura do reservatório de resina, o teor de carbonato de cálcio e o teor de fibra de vidro influenciaram de forma significativa nas propriedades das barras pultrudadas. Por fim, este estudo mostrou que é possível melhorar as características destes compósitos e, desta forma, desenvolver materiais que apresentem melhor qualidade e desempenho. / Pultrusion is one of several manufacturing processes of polymer composites. Its operating principle involves the use of a set of reinforcing fibers pre-impregnated with a thermoset resin which run through the interior of a heated die in order to cure the resin and to form a solid profile. Many processing variables such as die temperature, pulling speed, fiber impregnation, resin viscosity, among others, affect the process efficiency as well as the quality and performance of the pultruded composites. In this research, the influence of the glass fiber content, calcium carbonate content and the temperature of the resin bath on the mechanical properties, such as tensile strength, elastic modulus, elongation at break and superficial hardness of solid rods made with an unsaturated polyester resin and a single organic peroxide were investigated. It was observed that pultrusion process can be carried out using a single reaction initiator. In addition, the results showed that the temperature of the resin bath, the calcium carbonate and the glass fiber content have influenced significantly in the properties of the solid rods. Finally, this study showed that it is possible to improve the characteristics of such composites and, therefore, to develop materials that have good quality and performance.

Theoretical part of master's thesis is focused on chemical treatments of natural fibers and their use as reinforcement material in polymer composites. Flax fibers were treated with two different silane coupling agents to improve their adhesion with polymer matrix. Nature of treatment was studied by using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Composites based on both treated and untreated flax fibers were prepared by pultrusion.technique. Mechanical properties and water absorption of prepared composites were evaluated.

A fiber reinforced polymer (FRP) composite cellular deck system was used to rehabilitate a historical cast iron thru-truss structure (Hawthorne St. Bridge in Covington, Virginia). This research seeks to address following technical needs and questions to advance FRP deck application. The critical panel-to-panel connections were developed and evolved through a four-stage study and finally realized using full width, adhesively bonded tongue and groove splices with scarfed edges. Extensive experimental study under service, strength and fatigue loads in a full-scale two-bay mock-up test and a field test was performed. Test results showed that no crack initiated in the joints under service load and no significant change in stiffness or strength of the joint occurred after 3,000,000 cycles of fatigue loading. Various issues related to constructability of FRP deck systems were investigated and construction guidelines and installation procedures for the deck system were established. The structural performance of the FRP-on-steel-superstructure system was examined in the laboratory and field under service load. Tests results confirmed the following findings: (1) the clip-type of panel-to-stringer connection provides little composite action as expected, which fulfilled the design intention; (2) local effects play an important role in the performance of FRP deck; (3) the FRP deck design is stiffness driven rather than strength driven like traditional concrete deck. Finally, an FEM parametric study was conducted to examine two important design issues concerning the FRP decks, namely deck relative deflection and LDF of supporting steel girders. Results from both FEM and experiments show that the strip method specified in AASHTO LRFD specification (AASHTO 2004) as an approximate method of analysis can also be applied to unconventional FRP decks as a practical method. However, different strip width equations have to be determined by either FEM or experimental methods for different types of FRP decks. In this study, one such an equation has been derived for the Strongwell deck. In addition, the AASHTO LDF equations for glued laminated timber decks on steel stringers provide good estimations of LDFs for FRP-deck-on-steel-girder bridges. The lever rule can be used as an appropriately conservative design method to predict the LDFs of FRP-deck-on-steel-girder bridges. / Ph. D.

Fiber reinforced polymer (FRP) composites are considered very promising for infrastructure applications such as repair, rehabilitation and replacement of deteriorated bridge decks. However, there is lack of proper understanding of the structural behavior of FRP decks. For example, due to the localization of load under a truck tire, the conventionally used uniform patch loading is not suitable for performance evaluation of FRP composite deck systems with cellular geometry and relatively low modulus (compared to concrete decks). In this current study, a simulated tire patch loading profile has been proposed for testing and analysis of FRP deck. The tire patch produced significantly different failure mode (local transverse failure under the tire patch) compared to the punching-shear mode obtained using the conventional rectangular steel plate. The local response of a cellular FRP composite deck has been analyzed using finite element simulation and results are compared with full scale laboratory experiment of bridge deck and structure. Parametric studies show that design criteria based on global deck displacement is inadequate for cellular FRP deck and local deformation behavior must be considered. The adhesive bonding method is implemented for joining of bridge deck panels and response of structural joint analyzed experimentally. Strength, failure mode and fatigue life prediction methodologies for a cellular FRP bridge deck are presented in this dissertation. / Ph. D.

This project was sponsored by two companies interested in promoting the use of pultruded glass fibre/polyester composites in the construction of freight containers. Thus, the research was to understand and quantify the damage mechanisms caused by low velocity impact on the composite system and to produce a finite element impact model to further the understanding of these events.

This diploma thesis deals with evaluation of the conditions for laboratory testing of composite profiles with fiber-reinforced polymer (FRP). Theoretical part describes the main material properties of FRP profiles and method of manufacturing by pultrusion. Experimental part evaluates imposition of the test samples in alkaline environment and their subsequent changes in physical properties. Next part contains evaluation of cuts FRP profiles by electron microscopy in combination with element analysis. The outcome of this work is the method of evaluation of accelerated durability FRP profiles.

The article at hand presents a novel approach to accelerating the early strength development of mineralimpregnated carbon-fibre composites (MCF) by electrical Joule heating. MCF were produced with a metakaolin-based geopolymer suspension and subsequently cured using Ohmic heating under systemically varied voltages and durations. The MCF produced were characterised in respect of their mechanical and morphological properties. Threepoint-bending and uniaxial tension tests yielded significant enhancement of MCF mechanical properties due to curing within only a few hours. Thermogravimetric analysis (TGA), mercury intrusion porosimetry (MIP), environmental scanning electron microscope (ESEM) as well as micro-computed tomography (μCT) confirmed advanced geopolymerisation by the electrical heating process and a strong sensitivity to parameter selection. After only two hours of resistance heating MCF could demonstrate tensile strength of up to 2800 MPa, showing the great potential for applying the Joule effect as a possibility to enhance the strength development of geopolymer-based MCF. Moreover, the applied method offers a huge potential to manufacture automated fast out-of-oven cured MCF with a variety of shapes and dimensions.

No description available.

FRP stands for Fiber Reinforced Polymer. FRP materials have yet to be introduced inbridge construction in Sweden. Composite materials can through combined componentsand manufacturing processes be tailored to fit advanced bridge designs. FRP materials arestrong, durable and of low weight. FRP materials give the superstructure reduced weightand are therefore a suitable alternative for industrial prefabrication. This report shows thatFRP materials are possible to use in bridge construction. With the introduction of a specificEurocode we are confident that FRP materials will become a competitive alternative inbridge construction in Sweden in the future. / Broar är förenade med stora kostnader, dels för att bygga och dels för att underhålla ochreparera. FRP står för Fiber Reinforced Polymer är ett erkänt material för många andraanvändningsområden, exempelvis flyg och bilindustri. I Europa finns en mängd FRP-broar,men materialet har ännu inte introducerats i någon bro i Sverige.FRP är ett kompositmaterial som genom olika kombinationer av komponenter ochtillverkningsprocesser kan skräddarsys för den aktuella uppgiften i en konstruktion. FRPmaterialär starka, beständiga och har en låg vikt. Fördelar med FRP inom brokonstruktionär att det ger överbyggnaden en minskad egenvikt och därmed är ett lämpligt alternativ attprefabricera industriellt, då bland annat transport- och lyftbarhet gynnas samt att en högbeständighet ger minskat underhåll.Då ingen litteratur hanterar FRP i Brokonstruktion har de intervjuades åsikter varit mycketviktiga för arbetet. Litteraturstudien har legat till grund för en ökad förståelse för egenskaperutmärkande för olika typer av FRP. Intervjuer har utförts med personer som i dagslägetkommit i kontakt med materialet inom brokonstruktion. Detta har gjorts för att nå ett relevantresultat med möjlighet att kunna identifiera materialets för- respektive nackdelar samtanledningen till det låga användandet i Sverige.Rapporten visar att materialet har positiva egenskaper och är möjligt att använda vidkonstruktion av broar. Det saknas i dagsläget en specifik Eurokod som på ett enhetligt sättredovisar hur materialet ska hanteras. Med införandet av en specifik Eurokod och om en nykompetens arbetas fram inom branschen är vi övertygade om att FRP-material kommer attbli ett konkurrenskraftigt alternativ vid brokonstruktion.