Дисертації з теми "Fibre durability"
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Fisher, Alex K. "Durability design parameters for cellulose fibre reinforced concrete pipes in aggressive environments." Thesis, Queensland University of Technology, 2003.
Знайти повний текст джерелаLevin, Klas. "Durability of Embedded Fibre Optic Sensors in Composites." Doctoral thesis, Stockholm, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3145.
Повний текст джерелаGurusamy, K. "The marine durability of steel fibre reinforced concrete." Thesis, University of Aberdeen, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234802.
Повний текст джерелаNordström, Erik. "Durability of sprayed concrete : steel fibre corrosion in cracks /." Luleå, 2005. http://epubl.luth.se/1402-1544/2005/02.
Повний текст джерелаNordström, Erik. "Steel fibre corrosion in cracks : durability of sprayed concrete." Licentiate thesis, Luleå tekniska universitet, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18249.
Повний текст джерелаGodkänd; 2000; 20070317 (ysko)
Homam, Sayed Mukhtar. "Durability of fibre-reinforced polymers (FRP) used in concrete structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0023/MQ50345.pdf.
Повний текст джерелаDe, Klerk Marthinus David. "The durability of natural sisal fibre reinforced cement-based composites." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96895.
Повний текст джерелаENGLISH ABSTRACT: The building industry is responsible for a substantial contribution to pollution. The production of building materials, as well as the operation and maintenance of structures leads to large amounts of carbon-dioxide (CO2) being release in the atmosphere. The use of renewable resources and construction materials is just one of the ways in which the carbon footprint of the building industry can be reduced. Sisal fibre is one such renewable material. Sisal fibre is a natural fibre from the Agave Sisalana plant. The possibility of incorporating sisal fibre in a cement-based matrix to replace conventional steel and synthetic fibres has been brought to the attention of researchers. Sisal fibre has a high tensile strength in excess of polypropylene fibre and comparable to PVA fibre. Sisal fibre consists mainly of cellulose, hemi-cellulose and lignin. The disadvantage of incorporating sisal fibre in a cement-based matrix is the degradation of the composite. Sisal fibres tend to degrade in an alkaline environment due to changes in the morphology of the fibre. The pore water in a cement base matrix is highly alkaline which leads to the degradation of the fibres and reduced strength of the composite over time. Sisal fibre reinforced cement-based composites (SFRCC) were investigated to evaluate the durability of the composites. Two chemical treatments, alkaline treatment and acetylation, were performed on the fibre at different concentrations to improve the resistance of the fibre to alkaline attack. Alkaline treatment was performed by using sodium hydroxide (NaOH), while acetylation was performed by using acetic acid or acetic anhydride. Single fibre pull-out (SFP) tests were performed to evaluate the influence of chemical treatment on fibre strength, to study the fibre-matrix interaction and to determine a critical fibre length. A matrix consisting of ordinary Portland cement (OPC), sand and water were used for the SFP tests. This matrix, as well as alternative matrices containing fly ash (FA) and condensed silica fume (CSF) as supplementary cementitious material, were reinforced with 1% sisal fibre (by volume) cut to a length of 20 mm. The OPC matrix was reinforced with untreated- and treated fibre while the alternative matrices were reinforced with untreated fibre. Alternative matrices containing varying fibre volumes and lengths were also produced. Three-point bending- (indirect), direct tensile- and compression tests were performed on specimens at an age of 28 days to determine the strength of the matrix. The remainder of the specimens were subjected to ageing by extended curing in water at 24˚C and 70˚C respectively and by alternate cycles of wetting and drying, after which it was tested at an age of 90 days from production to evaluate the durability of the fibre. An increase in fibre volume led to a decrease in compressive strength and peak tensile strength. The optimum fibre length at a volume of 1% was 20 mm for which the highest compression strength was recorded. The combination of alkali treatment and acetylation was the most effective treatment condition, followed by alkali treatment at low concentrations of sodium hydroxide. At higher concentrations of sodium hydroxide, a significant reduction in strength was recorded. The addition of supplementary cementitious materials also proved to be effective in mitigating degradation, especially in the cases where CSF was used. FA proved to be less effective in reducing the alkalinity of the matrix. However, the use of FA as fine filler resulted in higher strengths. Specimens manufactured by extrusion did not have superior mechanical properties to cast specimens. The conclusion was made that the use of sisal fibre in a cement-based matrix is effective in providing ductile failure. Chemical treatment and the addition of supplementary cementitious materials did improve the durability of the specimens, although degradation still took place.
AFRIKAANSE OPSOMMING: Die boubedryf is verantwoordelik vir 'n aansienlike bydrae tot besoedeling. Die produksie van boumateriale, sowel as die bedryf en instandhouding van strukture lei tot groot hoeveelhede koolstof dioksied (CO2) wat in die atmosfeer vrygestel word. Die gebruik van hernubare hulpbronne en boumateriale is maar net een van die maniere waarop die koolstof voetspoor van die boubedryf verminder kan word. Sisal vesels is 'n voorbeeld van 'n hernubare materiaal. Sisal vesel is 'n natuurlike vesel afkomstig vanaf die Agave Sisalana plant. Die moontlikheid om sisal vesels in 'n sement gebasseerde matriks te gebruik om konvensionele staal en sintetiese vesels te vervang, is tot die aandag van navorsers gebring. Sisal vesel het 'n hoër treksterkte as polipropileen vesels en die treksterkte vergelyk goed met die van PVA vesels. Sisal vesel bestaan hoofsaaklik uit sellulose, hemi-sellulose en lignien. Die nadeel verbonde aan die gebruik van sisal vesels in 'n sement gebasseerde matriks is die degradasie van die komposiet. Sisal vesels is geneig om af te breek in 'n alkaliese omgewing as gevolg van veranderinge wat in die morfologie van die vesel plaasvind. Die water in die porieë van 'n sement gebasseerde matriks is hoogs alkalies wat lei daartoe dat die vesel afgebreek word en die sterkte van die komposiet afneem oor tyd. Sisal vesel versterkte sement gebasseerde komposiete is ondersoek om die duursaamheid van die komposiete te evalueer. Twee chemiese behandelings, alkaliese behandeling en asetilering, is uitgevoer op die vesels teen verskillende konsentrasies om die weerstand van die vesels teen alkaliese aanslag te verbeter. Alkaliese behandeling was uitgevoer met natrium-hidroksied (NaOH) terwyl asetilering met asynsuur en asynsuurhidried uitgevoer is. Enkel vesel uittrek toetse is uitgevoer om die invloed van chemiese behandeling op veselsterkte te evalueer, om die vesel/matriks interaksie te bestudeer en om die kritiese vesellengte te bepaal. 'n Matriks wat uit gewone Portland sement (OPC), sand en water bestaan, is gebruik vir die enkel vesel uittrek toetse. Dieselfde matriks, sowel as alternatiewe matrikse wat vliegas (FA) en gekondenseerde silika dampe (CSF) as aanvullende sementagtige materiaal bevat, is versterk met 1% vesel (by volume) wat 20 mm lank gesny is. Die OPC matriks was versterk met onbehandelde- en behandelde vesels, terwyl die alternatiewe matrikse met onbehandelde vesels versterk is. Matrikse wat wisselende vesel volumes en lengtes bevat het is ook vervaardig. Drie-punt buigtoetse (indirek), direkte trek toetse en druktoetse is uitgevoer op proefstukke teen 'n ouderdom van 28 dae om die sterkte van die matriks te bepaal. Die oorblywende proefstukke is onderwerp aan veroudering deur verlengde nabehandeling in water teen 24˚C en 70˚C onderskeidelik en deur afwissilende siklusse van nat- en droogmaak waarna dit op 'n ouderdom van 90 dae vanaf vervaardiging getoets is om die duursaamheid van die matriks te evalueer. 'n Toename in vesel volume het tot 'n afname in druksterkte en piek treksterkte gelei. Die optimum vesel lengte teen 'n volume van 1% was 20 mm, waarvoor die hoogste druksterkte opgeteken is. Die kombinasie van alkaliese behandeling en asetilering was die mees effektiewe behandeling, gevolg deur alkaliese behandeling by lae konsentrasies natrium-hidroksied. Vir hoë konsentrasies natrium-hidroksied is 'n aansienlike afname in sterkte opgeteken. Die toevoeging van aanvullende sementagtige materiale was ook effektief om die degradadering van die vesels te verminder, veral in die gevalle waar CSF gebruik is. FA was minder effektief om die alkaliniteit van die matriks te verminder. Die gebruik van FA as fyn vuller het nietemin hoër sterkte tot gevolg gehad. Proefstukke wat deur ekstrusie vervaardig is, het nie beter meganiese eienskappe gehad as proefstukke wat gegiet is nie. Daar is tot die gevolgtrekking gekom dat sisal vesel in 'n sement gebasseerde matriks wel effektief is om 'n duktiele falingsmode te voorsien. Chemiese behandeling en die toevoeging van aanvullende sementagtige materiale het die duursaamheid van die proefstukke verbeter, alhoewel degradering steeds plaasgevind het.
Zhang, J. "The performance and environmental durability of pultruded glass fibre composite rebars." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/7354.
Повний текст джерелаPurnell, Philip. "The durability of glass fibre reinforced cements made with new cementitious matrices." Thesis, Aston University, 1998. http://publications.aston.ac.uk/13285/.
Повний текст джерелаHenault, Jean-Marie. "Approche méthodologique pour l’évaluation des performances et de la durabilité des systèmes de mesure répartie de déformation : application à un câble à fibre optique noyé dans le béton." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1113/document.
Повний текст джерелаStructural Health Monitoring is a key factor in life-cycle management of civil structures. Truly distributed fiber optic sensors, composed by an optoelectronic device paired with an optical fiber in a cable, provide strain profiles over several kilometers with a centimeter resolution. They are thus able to provide relevant information on large structures. However, a preliminary performance assessment is required prior to any industrial application. Due to shear deformation of the cable's protective coating, strain measurements provided by the measuring system may differ from actual strains in the embedding medium. A methodology, based on mechanical tests and modelling, was thus developed to determine the relationship between measured/actual strains. It was applied to determine the mechanical response of a specific cable embedded in concrete. Performance assessment method was applied to a specific measuring system. Tests were carried out under laboratory conditions on the fiber optic cable, out of the concrete medium in a first stage, and then embedded in concrete structures. It enabled to evaluate its components and standard uncertainties. The cable could not be replaced after being embedded in concrete. It is necessary to evaluate the ageing effects on its mechanical properties to use it for a long term period. A specific study was carried out to determine the cable durability under chemical, thermal and mechanical solicitations
Ammar, Mohamed Amine. "Bond durability of basalt fibre-reinforced polymers (BFRP) bars under freeze-and-thaw conditions." Thesis, Université Laval, 2014. http://www.theses.ulaval.ca/2014/30559/30559.pdf.
Повний текст джерелаThis thesis presents the test results of a study on the bond behavior of basalt fiber-reinforced polymers (BFRP) bars in concrete. Forty-five cylinders reinforced with BFRP bars and eighteen cylinders reinforced with glass fiber-reinforced polymer (GFRP) bars were tested in direct pullout conditions. Test parameters included the FRP material, the bar diameter, the bar’s embedment length in concrete and the number of freeze-and-thaw cycles (100 and 200 cycles). Bond-slip curves of BFRP and GFRP bars revealed similar trend. All BFRP specimens failed in a pullout mode at the bar-epoxy interface. The influence of various parameters on the overall bond performance of BFRP bars is analyzed. The BPE, modified-BPE, and CMR analytical models were calibrated to describe the bond-slip relationships of BFRP bars. Results demonstrate the promise of using BFRP bars as an alternative to GFRP bars in reinforcing concrete elements.
Zhu, Wenzhong. "Effect of ageing on durability and micro-fracture mechanism of fibre reinforced cement composites." Thesis, University of the West of Scotland, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259743.
Повний текст джерелаEtches, J. A. "Interfacial and durability aspects of extrinsic Fabry-Perot interferometric sensors in carbon fibre composites." Thesis, Cranfield University, 2003. http://hdl.handle.net/1826/779.
Повний текст джерелаPage, Jonathan. "Formulation et caractérisation d'un composite cimentaire biofibré pour des procédés de construction préfabriquée." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC244/document.
Повний текст джерелаThe economic issues linked to the rising costs of fossil resources, their scarcity, and the environmental impacts inherent in their manufacture and use, are leading the construction industry to move towards bio-based materials. The resources from biomass are then in the foreground, especially agricultural ones, including fibres from plants stems. Among these fibres, flax stands out because of its high mechanical properties and low density, and its availability in Normandy. The objective of this study is to develop an innovative composite material by combining flax fibres with a cement matrix, which will be used in prefabricated construction processes. After the fine characterization of the initial constituents, we first described in detail the development of plant fibre-reinforced mortars and concretes with a focus on the formulation methodology. Then we analysed the influence of the incorporation of flax fibres on the rheological properties (entrapped air, consistency, workability) and physico-chemical properties (pH, ATG). The physical properties (porosity, modulus of elasticity) and mechanical properties (compressive and tensile strength, toughness index) were measured by bending and compressive tests in the hardened state. These results clearly show that the presence of flax fibres significantly reduces the technological properties of cementitious pastes, because of the sensitivity of the fibres to the highly alkaline medium and their highly hydrophilic nature. The surface treatments of the experimental fibres (by using atmospheric plasma, cement grout coating, blast furnace slag or linseed oil) have effectively improved some properties of mortars, the degradation of the fibres within the cement matrix remain active over the long term (alkaline hydrolysis of the fibres and their mineralization under the action of calcium hydroxide). It therefore appears necessary to use alternative binders in an attempt to improve the durability of these plant fibre biocomposites. Thus, new formulations of mortars and concretes are proposed, in which the Portland cement is partially replaced by metakaolin / blast furnace slag or totally by sulfoaluminate cement, without prejudice to the rheological behaviour. The study of the new composites formulated with metakaolin or sulfoaluminate cement indicates high levels of mechanical strength and toughness. Their resistance to frost superior to conventional concrete or concrete incorporating glass fibres is due to the high air content (the fibres act as an air-entraining admixture)
Jia, Yunlong [Verfasser], and Bodo [Akademischer Betreuer] Fiedler. "Durability of flax fibre/bio-epoxy sustainable composites for structural application / Yunlong Jia ; Betreuer: Bodo Fiedler." Hamburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2020. http://d-nb.info/1205370765/34.
Повний текст джерелаBatuwitage, Chamila Rajeev Jayanath. "Evaluation of environmental durability and bond characteristics of carbon fibre reinforced polymer (CFRP) strengthened steel structures." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/106775/1/Chamila%20Rajeev%20Jayanath_Batuwitage_Thesis.pdf.
Повний текст джерелаSato, Taijiro. "An AC impedance spectroscopy study of the freezing-thawing durability of Wollastonite micro-fibre reinforced cement paste." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6357.
Повний текст джерелаChilali, Abderrazak. "Étude expérimentale et modélisation de la durabilité des biocomposites à fibres de lin." Thesis, Reims, 2017. http://www.theses.fr/2017REIMS003/document.
Повний текст джерелаIn this thesis work, we study the durability of two twill flax fabrics reinforced thermosetting and thermoplastic composites. Firstly, the diffusion behaviour of these composites is investigated by identifying their 3D Fick’s and Langmuir’s diffusion parameters using an optimization algorithm. The influence of several geometric parameters and fibre orientation on their 3D moisture diffusion is also studied. Then, we analyse the effect of water ageing on their elastic and failure properties. Finally, a numerical finite element analysis is performed in order to study their diffusive and hydro-mechanical behaviour. The water diffusion parameters of the flax fibre and the used resins are estimated by a numerical inverse analysis exploiting experimental water uptake data. The heterogeneity of the studied composites is considered by modelling the twill weave fabrics undulation of their unit-cell. In particular, the mechanical behaviour of the unaged composites is found to exhibit a Kaiser effect contrary to the aged materials which exhibit a significant Felicity effect synonymous of substantial damage induced by water ageing. Besides, it is found that high mechanical stress concentrations are developed at the fibre-matrix interface, which could cause damage initiation and lead to the final composite failure
Poussines, Laurence. "Développement de nouveaux matériaux pour l'infusion de composites." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0132/document.
Повний текст джерелаThe work presented in this thesis was done to adapt a polymer to selected elaboration process by infusion of a composite material structure for an aircraft fuselage. The polymer system must meet certain requirements such as viscosity, infusion temperature, storage but also the price. Our methodology is to understand the process putting into practice in order to validate the resins choice, to characterize the initial state and the study their sustainability towards a hydrothermal ageing. Properties characterization showed different behaviours in initial state, in terms of glass transition, resilience and viscosity. The study of hydrothermal ageing reveals a drop properties closely related to the chemical evolution of polymer networks which has for major origin multiple links hydrolysis. At least an adherence test is carried out to assess the interface fiber/resin. This test was used to estimate the different surface treatments on the fiber
Römhild, Stefanie. "Transport Properties and Durability of LCP and FRP materials for process equipment." Doctoral thesis, KTH, Polymera material, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-13221.
Повний текст джерелаQC20100629
Sinicropi, Daniela [Verfasser], and Prof Dr Ing Harald [Akademischer Betreuer] Budelmann. "Experimental Investigation on the Durability of Fibre Reinforced Cementitious Materials for Strengthening of Masonry / Daniela Sinicropi ; Betreuer: Prof. Dr.-Ing. Harald Budelmann." Braunschweig : Technische Universität Braunschweig, 2015. http://d-nb.info/1175819085/34.
Повний текст джерелаHazra, Kalyan. "The influence of stitch architecture in multiaxial warp-knit fabrics on the damage tolerance and environmental durability of carbon fibre-reinforced composites." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/34825.
Повний текст джерелаHallonet, Anne. "Développement et caractérisation d'un matériau composite à base de fibres de lin : application au renforcement de structures en béton par collage externe." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1111/document.
Повний текст джерелаTo extend their life and ensure the safety of users, concrete structures may need strengthening during their service life. The technique of strengthening by external bonding of composites carbon, glass or aramid composites using polymer that are cured at room temperature is widely used for its effectiveness and ease of implementation. Yet the uses of both synthetic fibers and polymer matrices have a significant environmental impact. The objective of this research is to examine the possibility of using flax fibers for the external strengthening of concrete structures. Their high specific mechanical properties and positive environmental balance make them an interesting alternative to the glass fibers. However, they also present a larger variability in properties, a non-linear tensile behavior and high sensitivity to humidity. The main objectives of this thesis involve the selection of the materials and the most suitable implementation, the evaluation of the materials’ performances and adherence to concrete support and a sustainability assessment of those properties. In a first experimental section, two methods of implementation of the flax fiber reinforcement are developed and characterized: by wet lay-up and by bonding of pre-hardened. Tomography observations confirm the good fiber impregnation and cohesion of the composites. The tensile tests show a bilinear tensile behavior as described in the literature, with stress per width at failure comparable to glass fibres strengthening systems. The characterization of composite/concrete interfaces is conducted by double overlap shear tests and confirms a good adhesion which results in concrete failure before the failure of the reinforcement system. The nature of the fibers does not appear to influence the shear behavior of the interface. For glass or flax wet lay-up systems, failure can occur with failure of the composite. Flax fiber reinforcement systems can take up the forces transmitted by shear in a manner comparable to glass composites. In the second part, sustainability tests were conducted to ensure the sustainability of the properties of these two composite reinforcements in a service environment. An artificial accelerated aging test in a climatic chamber is set up while wet lay-up flax fiber composites are exposed to the external environment during a year. A second hydrothermal aging test is conducted for 4 weeks at 70°C. The degradations of the properties of the flax composites are comparable to those of some glass reinforcement composites. Despite the hydrophilic nature of the flax fibers the first tests show no degradation of properties that would make the composite unsuitable for an external reinforcement of concrete structures
Estoup, Jean-Marie. "Etude de la carbonatation endogene du beton et de ses applications a l'industrie du beton manufacture." Paris 6, 1987. http://www.theses.fr/1987PA066362.
Повний текст джерелаSeghini, Maria Carolina. "Mechanical Analysis and Fibre/Matrix Interface Optimization for Next Generation of Basalt-Plant Fibre Hybrid Composites." Electronic Thesis or Diss., Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2020. http://www.theses.fr/2020ESMA0003.
Повний текст джерелаGlobal awareness of environmental issues has resulted in the emergence of “green” composites, in which natural fibres are used to replace synthetic ones. However, in semi-or structural applications, it can be inconvenient to use composites based on natural fibres. A possible solution to this problem is the development of hybrid composite materials, combining together plies of natural and synthetic fibres. In this framework, the aim of this research project was to develop basalt-flax fibre hybrid composites with a view to obtaining more environmentally friendly composites for semi-structural applications. Hybrid composites were produced through vacuum infusion molding with epoxy matrix.For comparison purposes, 100% flax fibre composites and 100% basalt fibre composites were also manufactured. A quasi-static and dynamic mechanical characterization showed that the hybridization allows the production of a composite with intermediate mechanical performances compared to those possessed by flax and basalt composites. However, the damage analysis has revealed the need to optimize the fibre/matrix interface adhesion quality, in order to increase the mechanical properties of the resulting hybrid composites. For this reason, different surface modification treatments have been specifically designed and investigated for flax and basalt fibres. Flax and basalt fibres were treated by the physical process of Plasma Enhanced Chemical Vapor Deposition. Flax fibres were also subjected to two chemical treatments using enzymatic species and supercritical CO2. The effects of the surface modification treatments on the thermal stability, morphology and mechanical properties of flax and basalt fibres have been investigated. The degree and extent of fibre/matrix adhesion were analyzed by micromechanical fragmentation tests on monofilament composites. The adhesion quality between fibres and both epoxy and vinylester matrices has been assessed in terms of critical fragment length, debonding length and interfacial shear strength. High-resolution μ-CT has been used to support the analysis of the damage mechanisms during fragmentation tests. For both flax and basalt fibres, the best results were obtained after the plasma polymer deposition process. This process was able to produce a homogeneous tetravinylsilane coating on the surface of basalt and flax fibres, which resulted in a significant increase in the fibre/matrix adhesion, thus paving the way for the next generation of more environmentally friendly hybrid composites for semi-structural applications
Méchin, Pierre-Yves. "Contribution à l’étude de la résistance à la compression de stratifiés composites à fibres de carbone haut module : cas de chargements statiques et cycliques." Thesis, Lorient, 2017. http://www.theses.fr/2017LORIS434.
Повний текст джерелаThis PhD dissertation is a contribution to the modelling of Carbon-Fiber-Epoxy-Polymer laminates, undergoing specifically compression loadings, according to components. The aim is to build a design tool for composites structures taking into account this compression specificity for dimensioning racing yachts parts (masts, daggerboards, foils), which is the expertise of HDS/GSea-Design, the company associated to this work. Emphasis was put on the influence of linear or non-linear properties of each phase by varying the type of fibre (from high stiffness to high strength) and the type of matrix (from brittle to ductile). The effect of a mechanical loading, static, constant (creep, relaxation) or variable (fatigue) on durability is studied and a numerical model for predicting the residual strength is proposed. The first part of this work deals with the mechanisms involved in compressive strength. An analytical model is used for an experimental validation. It considers a contribution linked to the micro-buckling of the fibre as contained by the shear behaviour of the matrix (Budiansky et Fleck [1993]). It considers also a contribution of the deformation gradient induced for instance in a bending loading (Gardin et al. [2002]). To validate this model, an experimental campaign was conducted on six different epoxy matrices (from brittle to ductile) on identical monolithic stackings processed in autoclave. The results allowed the validation of the model capability to predict the influence of the matrix stiffness on the compressive strength of unidirectional laminas. Taking into account the matrix behaviour validates the micro-buckling contribution. Regarding the deformation gradient contribution, it is validated through a comparison using additional experimental results on sandwich samples in bending. The latter samples were specifically designed to favour a pure compression fracture (without any deformation gradient). The second part examines durability in compression. Another experimental campaign with fatigue tests was conducted with four points bending tests on the same sandwich samples. Experiments were carried out at 10 Hz and different load ratios were used to study their influence on the compressive residual strength. A numerical model involving different scales (laminate, laminas, fibres and matrix) is developed in parallel (Huang et al. [2012a]), based on the degradation and the plasticity of the matrix. The assumption of thermo-rheological simplicity of the matrix is made to build master curves from dedicated experiments (creep, relaxation). We then use the residual properties (stiffness, strength) of the ply to estimate a damage level. This latter parameter is used to modify the elastic stiffness of the matrix with a linear law. A Miner-type cumulative law is used in fatigue to take into account the different possible loadings. A micro-mechanical solver is developed to extract the non-linear shear behaviour of the ply accounting for this degradation. This behaviour is described by a Ramberg-Osgood law used in the analytical model described in the first part of this work. The joint contributions of these two parts allowed us to program a numerical tool for predicting the residual strength of plies undergoing a biaxial in- plane loading, being monotonous, constant or with a variable amplitude, with emphasis on the particular case of compression loading
Ponsot, Bernard. "Influence de la matrice sur le comportement a long terme de composites carbone-epoxyde." Paris, ENMP, 1987. http://www.theses.fr/1987ENMP0058.
Повний текст джерелаButler, Marko, Simone Hempel, and Viktor Mechtcherine. "Zeitliche Entwicklung des Verbundes von AR-Glas- und Kohlenstofffaser- Multifilamentgarnen in zementgebundenen Matrices." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1244045698955-31655.
Повний текст джерелаVève, Jean-Christophe. "Interpretation microstructurale de l'endommagement par fatigue mecanique des fibres de polyester pour le renforcement des elastomeres." Paris, ENMP, 1987. http://www.theses.fr/1987ENMP0065.
Повний текст джерелаRaman, Venkadesh. "A smart composite based on carbon fiber and epoxy matrix for new offshore wind-turbines. Multi-scale numerical and analytical modelings." Thesis, Ecole centrale de Nantes, 2017. http://www.theses.fr/2017ECDN0016.
Повний текст джерелаSmart structures have been developed as to monitor structures that have to operate in demanding industrial applications with includes harsh environments (Aeronautics and aerospace, Civil engineering, nuclear and chemical power plants…), too. Current study is focused on the suggestion of new smart composite materials that can be successfully used for wind blade structures in offshore energy generation farms. Indeed, to bring expectable energy-generation performances, new generation wind blades have to exceed 100m length, which is a hardly achievable target given that actual constitutive composite materials are based on glass-fibers, that are notably known to be very heavy and lacking stiffness. Therefore, the switch to carbon fibers (lighter and stiffer) becomes mandatory. In this thesis, we propose the implementation of a smart composite material that is based on carbon fibers and epoxy matrix (here called parent material). Fiber Optic Sensors (FOS) and Quantum-Resistive Sensors (QRS) will be used for detection of over-strained areas all over the structure. This choice is expected to enable for accurate documentation and instant sending of critical information to engineers. To achieve this goal of development of a new smart material for a critical application in offshore wind generation, we have chosen to illustrate it in a research document that is grouping several aspects, summarized in 5 chapters. The thesis is conducted using numerical and analytical modelings. The document is not having the ambition to be exhaustive. It is intended to present a pragmatic research that emphasize how areas of mechanical weakness can be diagnosed, what are the solutions that can be suggested and how we can support them, what are the issues pertaining to the use of embedded sensors and some experimental results that give appraisal of current performance status and what could be future trends
Mazáč, Jan. "Využití kevlarových vláken v asfaltových směsích." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240054.
Повний текст джерелаGodoy, Vinícius Batista. "Desempenho de misturas de distintos materiais com cinza volante e cal submetidas a condições climáticas severas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/178361.
Повний текст джерелаThe practical application of industrial residues, such as coal fly ash, on bases and sub-bases of highways, is of great interest to geotechnical engineers, since it reduces the consumption of natural resources and gives a destination to these residues. In this sense, this master's thesis evaluates the performance of coal fly ash-lime mixtures under extreme climatic conditions. Was analysed the impact of the hydrated lime content (3%, 5%, 7%), the degree of compaction (14.0 kN/m³, 15.0 kN/m³, 16.0 kN/m³), the addition of 0.5% sodium chloride (NaCl) as a catalyst and the addition of 0.5% polypropylene fibers, on strength, stiffness and durability (comparing freezing-thawing to wetting-drying cycles), in fly ash mixtures (25%) with Osório sand. The influence of temperature (23 °C and 40 °C) in a period of 7 days of cure was also studied, this increase in temperature has been shown to provide high durability (for freezeing-thawing cycles), strength and stiffness gains, as well as addition of salt and polypropylene fibers. In order to extend this research, it was propose the exchange of the matrix’s mixture (Osório sand) by reclaimed asphalt paving (RAP) and lime hydrated by carbide lime For this new type of mixture, triaxial tests are also performed to analyze the stress-strain behavior in relation to the addition of 0.5% NaCl, where a 3.4° increase in the friction angle was observed, and 42.8 kPa in the cohesive intercept. The mixtures of RAP and carbide lime obtained better strength and durability results than mixtures with Osório sand and dolomitic lime, for the same cure temperature. Subsequently, It was verified that the accumulated loss of after these kinds of cycles is controlled by the index of porosity (η) / volumetric content of lime (Liv), for both mixtures. Besides that, lower losses of accumulated mass was observed for the wetting and drying cycles, compared to the freezing and thawing cycles.
Phéron, Xavier. "Durabilité des capteurs à fibres optiques sous environnement radiatif." Phd thesis, Université Jean Monnet - Saint-Etienne, 2013. http://tel.archives-ouvertes.fr/tel-01058775.
Повний текст джерелаMohr, Benjamin J. "Durability of Pulp Fiber-Cement Composites." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7222.
Повний текст джерелаKrishnaswamy, Vijayarajan. "Durability of nanoclay FRP bars for concrete members." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4568.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains xvi, 204 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 155-158).
Chlela, Robert. "Durabilité d'un système composite biosourcé (matrice époxy-fibres de lin) pour applications de renforcement structural : approches expérimentale et fiabiliste." Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC2076.
Повний текст джерелаIn France, the built heritage of civil engineering and building structures is vast and ageing. Recent reports prepared by experts highlight this alarming situation and point out the need to significantly increase the resources allocated to the rehabilitation of this heritage. In this context, structural reinforcement by externally bonded composites has become an attractive solution for the rehabilitation of structures and the extension of their lifespan. This thesis, funded by the French Research Agency (ANR), aims to develop a new composite reinforcement system with a reduced environmental footprint, on one hand, and to build an original reliability approach to estimate the lifetime of reinforcement systems and their failure probability at any time, on the other hand. In this manuscript, the main phases of development of the bio-based system are first recalled. In particular, it is recalled that the formulation of the bio-sourced epoxy matrix was based upon the specifications and characteristics of the Foreva® TFC matrix, and the criteria that guided the choice of the unidirectional flax fibre reinforcement fabric are also presented. The second part of the manuscript presents all the experimental results obtained within the framework of the durability study on the bio-based strengthening system. This test campaign relies on a Design of Experiment optimized by Hoke’s matrix. Laminated composite plates and concrete slabs reinforced with these composites were subjected to accelerated ageing under hygrothermal conditions, and to natural ageing on an outdoor exposure site in Lyon as well, for a total duration of 24 months. In a first step, the results of various physico-chemical characterizations that were periodically conducted on the bio-based composites, highlighted the relative contributions of mechanisms involved in microstructural evolutions and degradation phenomena of both the polymer matrix and fiber/matrix interfaces. In a second step, the changes in the main performance indicators related to the composite and the concrete-composite interface subjected to the various ageing environments, are presented and interpreted in the light of the previous physico-chemical characterizations. In a third step, a comparison is made between the bio-based composite system and a traditional carbon fibre strengthening system. The last part of the manuscript is devoted to the implementation of the reliability approach, relying on the experimental database previously collected for the bio-based system. A statistical analysis by the ANOVA method is first carried out on all experimental data. Two degradation models were then developed to describe the evolutions of performance indicators over time for any hygrothermal ageing condition: an analytical model with explicit terms related to quadratic effects and coupling between temperature and relative humidity, and a physical model based on Eyring's law.In a next step, these models were used to estimate the lifetime of the bio-based strengthening system under accelerated ageing conditions. End-of-life criteria were first defined based on specifications proposed by different design guidelines, in particular by ACI and AFGC reports.In order to evaluate the lifetime under actual service conditions, a specific procedure was then proposed to apply the analytical model in the case of natural ageing. Finally, a probabilization of the analytical model is carried out in order to determine the probability of failure of the bio-based strengthening system at any time during its lifetime
Gilani, Adel Mohamed. "Various Durability Aspects Of Slurry Infiltrated Fiber Concrete." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608753/index.pdf.
Повний текст джерелаKodkani, Shilpa. "Interface durability of externally bonded GFRP to normal and high-performance concrete." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3601.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains xiii, 147 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 141-147).
Bouhet, Jean-Charles. "Étude de l'impact de l'humidité et de l'alcalinité sur des armatures de polymères renforcés de fibres (PRF)." Mémoire, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/8054.
Повний текст джерелаAbstract : The FRP rebars technology remains relatively recent and suffers from a bad reputation in terms of durability which slows its acceptation among the professionals of the construction field. The aim of the work presented in this essay is to study the effects of moisture and alkalinity on the mechanical and thermo mechanical performances of FRP rebars. Nowadays, the progressions of FRP performances have been widely studied by different researchers but we still have few knowledge about the modes of degradation which lead to performance losses. The final goal of this work is to find investigation trails for the understanding of those degradation mechanisms which could possibly be taken over as part of a thesis work. The work is divided into two projects. The first one is the study of accelerated aging of glass fibers reinforced polymer (GFRP) rebars, of different diameters, conditioned in a moist environment. The second one concerns the behavior of GFRP and basalt fibers reinforced polymer (BFRP) rebars, of same diameter, conditioned in an alkaline environment which simulates the interstitial solution of concrete.
Conroy, Paul James. "Durability of glass and ceramic fibres within the lung." Thesis, Sheffield Hallam University, 1990. http://shura.shu.ac.uk/19497/.
Повний текст джерелаHuang, Xinyu. "Mechanics and Durability of Fiber Reinforced Porous Ceramic Composites." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/26063.
Повний текст джерелаPh. D.
Avena-Barthelemy, Anne. "Comportement a long terme de materiaux composites immerges a grande profondeur." Paris, ENMP, 1987. http://www.theses.fr/1987ENMP0049.
Повний текст джерелаAlbrektsson, Joakim. "Durability of fire exposed concrete : Experimental Studies Focusing on Stiffness & Transport Properties." Licentiate thesis, KTH, Betongbyggnad, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-168386.
Повний текст джерелаQC 20150603
Rolland, Arnaud. "Comportement mécanique et durabilité de structures en béton renforcées par des armatures composites internes." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1065/document.
Повний текст джерелаCorrosion of the steel reinforcing bars (rebars) is the main process involved in the degradation of reinforced concrete (RC) structures, and has large repercussions on the maintenance/reparation expenses. To prevent such degradations on new infrastructures, the use of corrosion-free reinforcements, such as Fiber Reinforced Polymer (FRP) bars based on glass, carbon or aramid fibers, is gaining interest. Specific guidelines are already available in several countries (USA, Canada or Japan for instance), that define the design principles and good practices for this type of internal rebars; beside, many FRP RC structures have been built and are in service in these countries. Although the development of these new reinforcing bars is quite promising, infrastructures owners are still reluctant for their wide-scale use, especially in France. There are still major concerns regarding the long term behavior of FRP RC structures, and more particularly, the durability of glass fibers reinforced polymers (GFRP) when subjected to an alkaline environment, and the ageing behavior of the GFRP/concrete bonding as well. In this context, the present study aims at developing for the first time in France, a set of methodologies that allows : to characterize the main physical/mechanical properties of different types of FRP bars from the marketto assess the durability of GFRP bars (the most common type of bar) and their interface with concrete through relevant accelerated ageing procedures. The first part of this study was thus devoted to the physical/mechanical characterization of a selection of commercially available FRP rebars, based on glass, carbon or aramid fibers, and to the mechanical behavior of corresponding FRP/concrete interfaces. Beside the microstructural characterization of the various FRP materials by microscopy and thermal analysis techniques, tensile and short beam tests were developed in order to determine the tensile properties (Young's modulus and strength) and the interlaminar shear strength (ILSS) of the bars. Specific pull-out tests then made it possible to evaluate the influence of several parameters (type of fibers, diameter and surface geometry of the bars) on the mechanism of load transfer at the bar/concrete interface. A main originality of the proposed approach relied on the instrumentation of several test bodies by optical fiber strain sensors, which were installed along the bar/concrete interface. Such a distributed measurement system provided local information in the form of tensile strain profiles of the bars along the interface, and made it possible to determine the effective transfer length of the various types of FRP bars. As a complement to the previous experimental study, an analytical and numerical modeling work was initiated to simulate the pull-out tests and investigate more closely the interfacial mechanisms involved in the FRP bar/concrete bond behavior. In this line, an improved interface model was first proposed, which was then implemented in a finite element model (cohesive zone model formulated in the context of damage mechanics).Finally, an accelerated ageing protocol was developed and applied to the GFRP bars, either alone or embedded in a concrete medium. The retention properties of both bars and interfaces were determined after various periods of exposure (up to 240 days). Except a drop of tensile properties observed for GFRP bars that were directly immersed in an alkaline solution, which is considered as a very severe environment compared to actual service conditions, no significant loss of interfacial properties was detected on aged specimens compared to the initial state
Akhtarkhavari, Afsaneh. "Adhesion and durability of latex paint on wood fiber reinforced polyethylene." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0015/MQ53339.pdf.
Повний текст джерелаDarmawangsa, Darmadi. "Optical fiber sensors embedded in concrete structures : feasibility and durability studies." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/40154.
Повний текст джерелаIncludes bibliographical references (leaves 292-295).
by Darmadi Darmawangsa.
Civ.E.
Deng, Jiangang. "Durability of carbon fiber reinforced polymer (CFRP) repair/strengthening concrete beams." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1663060011&sid=2&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Повний текст джерелаHaskell, Adam Benjamin. "A Durability and Utility Analysis of EFPI Fiber Optic Strain Sensors Embedded in Composite Materials for Structural Health Monitoring." Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/HaskellAB2006.pdf.
Повний текст джерелаRabii, Hajer. "Étude du vieillissement de composites renforcés par des fibres naturelles : application bâtiment." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1147/document.
Повний текст джерелаThe use of bio-based composites in outdoor applications for civil engineering raises the issue of their sustainability in service. This is mainly due to the highly hydrophilic character of natural fibers. Indeed, the behavior of these composites in a wet environment or under thermal and biological constraints is not well known. The main objective of this study is to get a better understanding of the reversibility of bio-based composites properties. Therefore, wetting/ drying cycles were performed on polyethylene/short flax fibre composites under hydro and hygrothermal ageing at 30 and 80°C. The influence of the fiber content and the interface quality on the mechanical properties was monitored. Moreover, a 6 months study of a microbial growth impact on these composites was carried out. A characterization of the non-aged materials was conducted first. Then, the kinetic parameters such as the water diffusion coefficient and the weight changes due to ageing were determined. Two competing mechanisms seem to affect the diffusion coefficient. The mechanical characterization of these composites during aging has enabled the identification of the aging mechanisms. Changes in the mechanical modulus at 30°C were mostly reversible after a drying cycle and were associated with a plasticizing effect of the water molecules on the cellulose microfibrils. The property losses increase and become irreversible at 80°C, which indicates a higher degradation of the composites. Finally, the biological degradation of these materials has been studied. It was verified that selective consumption of flax fiber components by microorganisms occurs, and that their growth is favored by the fiber content in the composite
Jackson, Nicole Danielle. "Reliability-based durability assessment of GFRP bars for reinforced concrete." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/35825.
Повний текст джерелаPrior to conducting the simulation, long-term GFRP tensile strength values needed to be ascertained. Existing FRP tensile strength models are limited to short-term predictions. This study successfully developed a power law based-FRP tensile strength retention model using currently available tensile strength data for GFRP exposed to variable temperatures and relative humidity. GFRP tensile strength retention results are projected at 0, 1, 3, 10, 30, and 60-year intervals. The Monte Carlo simulation technique is then used to assess the influence beam geometry, concrete strength, fractions of balanced reinforcement ratio, reinforcing bar tensile strength, and environmental reduction factors on the flexural capacity of GFRP reinforced concrete beams.
Reliability analysis was successfully used to determine an environmental reduction factor of 0.5 for concrete exposed to earth and weather. For simulations with higher GFRP bar tensile strength as well as larger beam geometry and fractions of the balanced reinforcement ratio, larger moment capacities were produced. A strength reduction factor of approximately 0.8 is calculated for all fractions of balanced reinforcement ratio. The inclusion of more long-term moisture data for GFRP is necessary to develop a more cohesive tensile strength retention model. It is also recommended that longer life cycles of the GFRP reinforced concrete beams be simulated.
This research was conducted thanks to support from the National Science Foundation Division of Graduate Educationâ s Interdisciplinary Graduate Education Research and Traineeship (Award # DGE-0114342) Note: The opinions expressed herein are the views of the authors and should not be interpreted as the views of the National
Science Foundation.
Master of Science