Résumé : La technologie des armatures en matériaux composites de polymères renforcés de fibre (PRF) reste relativement récente (moins de 20 ans) et souffre d’une moins bonne réputation en termes de durabilité, ce qui tend à freiner son acceptation par les professionnels du secteur. Les travaux présentés dans ce mémoire ont pour but d’étudier les effets de l’humidité et de l’alcalinité sur les performances mécaniques et thermomécaniques de barres d’armature en PRF. Si de nos jours l’évolution des propriétés des armatures de PRF a été largement étudiée par différents chercheurs, nous n’avons que peu d’informations sur les modes de dégradation qui entrainent ces pertes de performances. Le but des travaux entrepris dans ce mémoire est de trouver des pistes d’investigation pour la compréhension de ces mécanismes de dégradation qui pourraient éventuellement par la suite être reprises dans le cadre de travaux de thèse. Les travaux qui ont été entrepris s’articulent autour de deux projets. Le premier s’intéresse à l’étude du vieillissement accéléré de barres de polymère renforcé de fibres de verre (PRFV) de différents diamètres et soumis à un environnement humide. Le second s’intéresse à l’étude de barres de PRFV et de polymère renforcé de fibres de basalte (PRFB) de même diamètre soumis à un environnement alcalin qui simule le milieu interstitiel du béton. / Abstract : 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.

<p>The built environment usually constitutes a very importantpart of the real capital of a nation and the constructionsector represents more than 10% of the yearly Gross NationalProduct of the industrialised world. The importance of goodplanning of all construction, where the service life of thework is considered, is of great interest and an importantaspect in sustainability considerations. The need for increasedknowledge about degradation of materials, for structuredmethodology, and for working tools for those involved in theplanning process, has resulted in an extensive effort inpre-normative research and standardisation regarding thisfield.</p><p>This thesis presents a discussion on service life planningand the role of the Factor Method in such a work, andespecially, discussion of modification and development of themethodology. In the design process, the need to evaluate theservice life of products is great, and this is a formidableproblem to solve, as the results will depend on both materialproperties and the environment in which the material is placedor used. A practical solution has to be based on a goodknowledge in the field, but also on a sound working strategy,to ensure that different design scenarios can be compared in astandardised or structured way. The Factor Method is apromising working tool for such an evaluation and comparison,but is as such, still more of a methodology, than a method.Examples of the use of the methodology are still very limitedand the method as such, is much discussed by researchers.However, its future will depend on how practical it will be toapply in use. The method is useful to estimate the service lifeof products, based on a known reference service life and anumber of modifying factors that will depend on the conditiondifferences between the specific project and the referencein-use conditions. The required precision of such a methodologyis discussed, especially in the light of inherent distributionin material properties and the fact that often the consequencesof failure are very limited. In such cases, the standardisedFactor Method is considered to be of great use and should giveparties involved a good means for working in a structured andsystematic way.</p>

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<p>The built environment usually constitutes a very important part of the real capital of a nation, and the construction sector represents more than 10% of the yearly Gross National Product of the industrialised world. Good planning of all construction is important, and consideration of the service life of the work is of great interest and is a significant aspect of sustainability considerations. The need for more knowledge about degradation of materials, for structured methodology, and for working tools for those involved in the planning process, has resulted in an extensive effort in pre-normative research and standardisation regarding this field.</p><p>This thesis presents a discussion on service life planning and the role of the Factor Method in such work, and especially, discussion of modification and development of the methodology. In the design process, the need to evaluate the service life of products is a great challenge, as the results will depend on both material properties and the environment in which the material is placed or used. A practical solution has to be based on a good knowledge in the field, but also on a sound working strategy, to ensure that different design scenarios can be compared in a standardised or structured way. The Factor Method is a promising working tool for such an evaluation and comparison, but is as such, still more of a methodology, than a method. Examples of the use of the methodology are still very limited, and the method as such, is much discussed by researchers. However, its future will depend upon how practical it will be to apply in use. The method is useful to estimate the service life of products, based on a known reference service life and a number of modifying factors. These factors in turn depend on the conditional differences between the specific project and the reference, in-use conditions. This thesis discusses the required precision of such a methodology, especially in light of inherent distributions in material properties, and the fact that the consequences of failure are often very limited. In such cases, the standardised Factor Method is considered to be quite useful, and should give the parties involved a good means for working in a structured and systematic way. </p>

Conventional fiber reinforced polymers (FRPs) require polymers such as epoxies that are not biodegradable, which have a significant impact on the environment. The first phase of the thesis aims at replacing conventional polymers with sustainable bio-polymers. The tensile mechanical properties of glass-FRP (GFRP) laminates using two types of organic furfuryl alcohol bio-resins extracted from renewable resources, such as corncobs, were investigated. Results are compared to control specimens fabricated using conventional epoxy resin. It was shown that by careful selection of viscosity of bio-resin, and type and dosage of catalyst, similar mechanical properties to epoxy-GFRP can be achieved. The second and third phases consisted of durability testing of the bio-resin GFRP. A total of 160 tension coupons and 81 unconfined and confined concrete cylinders wrapped with bio-resin-GFRP were studied. Conditioning was achieved by immersion of the specimens in saline solutions with 3% salt concentration, at 23, 40 and 55 degrees Celcius, for up to 300 days. Specimens were compared to epoxy-GFRP specimens aged in the same environment. Deterioration was quantified by tensile testing of the coupons and compression testing of the cylinders at various stages of exposure. The bio-resin-GFRP showed 33% less tensile strength retention than the epoxy-GFRP. The epoxy-GFRP and bio-resin-GFRP wrapped cylinders had the same un-aged confined axial compressive strength (fcc’), essentially a strengthening ratio (fcc’/fc’) of 2.24. After 300 days, the (fcc’/fc’) ratio retentions for the bio-resin-GFRP was 73% at all temperatures. Using the Arrhenius model, it was predicted that 61% retention in tensile strength of the bio-resin-GFRP and 65% retention of the compressive strength of wrapped cylinders would occur after 100 years in an environment with a mean annual temperatures of 10 degrees Celcius. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-08-24 00:02:25.683

Adhesive joining is an attractive alternative to conventional joining methods, such as welding and mechanical fastening. The benefits of adhesive bonding include: the ability to form lightweight, high stiffness structures; joining of different types of materials; better fatigue performance, and reduction in the stress concentrations or the effects of the heat associated with welding. However, concerns about the durability of adhesive joints still hinder their widespread use in structural applications. Moisture has been identified as one of the major factors affecting joint durability. This is especially important in applications where joints are exposed to varying moisture conditions throughout their useful life. The aim of this research is to develop models to predict degradation in adhesive joints under varying moisture conditions. This was achieved by a combination of experimental and numerical methods. Experiments were carried out to characterise the moisture uptake and mechanical properties of the single part epoxide adhesive, FM73-M. Single lap joints were manufactured from aluminium alloy 2024 in heat treated (T3) and non heat treated (O) states using the FM73-M, BR127 adhesive-primer system. Tensile testing of the single lap joints was carried out after the joints had been exposed to hot-wet conditioning environments. Models were developed for predicting moisture concentration in the adhesive under cyclic moisture absorption and desorption conditions. A finite element based methodology incorporating moisture history was developed to predict the cyclic moisture concentration. In the next step, a novel finite element based methodology, which was based on moisture history effects, was developed to determine stresses in bonded joints after curing, conditioning and tensile testing. In the final step, a moisture history dependent cohesive zone element based damage and failure criterion was introduced to predict damage initiation, crack growth and failure under variable moisture and temperature conditions. The methodology proposed in this work and its implementation by finite element method provides a systematic approach for determining the degradation in adhesive joints under varying environmental conditions and accomplishes the aim of this research.

An experimental investigation is presented on a novel High Temperature Falling Particle Receiver for Concentrated Solar Power (CSP) to quantify the extent of erosion of the receiver structural materials by the flowing particulate matter. The current receiver design uses a series of metal wire mesh screens to slow down the particulate flow through the receiver in order to increase their residence time thereby achieving the desired temperature rise within the receiver without the need for particulate recirculation. The solid particulates are gravity fed through the receiver where they absorb the incident thermal energy before flowing to a high temperature storage bin upstream of a heat exchanger where the heat stored in the particulate material is transferred to the working fluid for the power cycle. To assess the effective life of the receiver, this experimental investigation is undertaken. This thesis includes the development of an apparatus to test wire meshes under high temperature and particle abrasion conditions, and the presentation and analysis of these results.

Using data from the 2000-2016 Major League Baseball seasons, this paper looks at the determinants of durability amongst baseball athletes, durability is measured in games played for batters and innings pitched for pitchers, with a particular focus on height and weight. This paper finds evidence that lighter, shorter batters play significantly more games than taller, heavier batters. Additionally, amongst pitchers, there is only circumstantial evidence that height and weight are important determining factors of player durability. Finally, I find that starting pitchers increase the likelihood of becoming injured in the regular season by 10.3% and 21.8% if their hits per nine innings and home runs per nine inning totals, respectively increase by one.

The aim of the thesis is to determine the levels of the physical and mechanical properties of chosen sedimentary (siliciclastic) rocks and also to describe their microstructural nature. With respect to the intended use of the studied material (building stone raw material) the laboratory testing methods are presented. The samples were taken from the drill cores and also from the surface blocks in locality "Zlatý lom" Březín situated in western Bohemia. The microstructural phenomena in the samples were studied using optical microscopy and digital image analyses. According to Folk's classification (1980) the name of the rock was lithic arkose. The strength testing methods were represented by unconfined compressive strength and the Brazilian test. The rest of the mechanical parameters were determined in form of Young's modulus, shear modulus and Poisson's ratio. Special emphasis was given to the hydric expansion (after full immersion) test. The other physical methods were used in order to describe the pore space and real density of samples. For this purposes the absorption test, mercury intrusion porosimetry and helium pycnometry were performed. Besides the porosity value, the pore-size distribution histograms were obtained. In order to calculate the theoretical density of the rock MINLITH and MODES...

Les géomembranes (GMB) en polyéthylène haute densité (PEHD) sont utilisées comme barrière d'étanchéité dans les installations de stockage de déchets non dangereux (ISDND). Malgré les bonnes propriétés initiales du PEHD, face aux agressions chimiques et biologiques d'un lixiviat de déchets et aux contraintes thermiques et mécaniques générées par le massif de déchets, sa durabilité reste une question ouverte. L'objectif de cette thèse est de contribuer au développement d'un modèle cinétique non empirique de prédiction de la durée de vie des GMB en PEHD, qui prend simultanément en compte les effets du vieillissement chimique et biologique. Pour cela, nous cherchons à déterminer d'une part les paramètres d'extraction des antioxydants constitutifs des GMB, première étape du vieillissement des GMB, et d'autre part les paramètres cinétiques de vieillissement oxydatif des PE, deuxième étape de vieillissement. Ceci nécessite de connaître et de comprendre les mécanismes physico-chimiques impliqués dans le vieillissement des PE dans les conditions particulières des ISDND. A partir d'une approche multi-échelle (macro- micro) et à l'aide de différentes techniques (IRTF, GPC HT, AED, essais de traction,…), nous évaluons l'impact du vieillissement accéléré sur la composition chimique, les structures macromoléculaire et cristalline ainsi que les propriétés d'usage des GMB et des films en PEHD. Cette étude a permis de déterminer un critère de fin de vie pertinent pour évaluer la durée de vie de la GMB : la fragilisation qui correspond à une masse molaire critique M'C d'environ 100 kg.mol-1. Un couplage de la modélisation chimique de la dégradation oxydante du polymère et biologique de la cinétique de croissance du biofilm est proposé. Enfin, dans une dernière partie, la même approche multi-échelle a été utilisée pour caractériser la dégradation de GMB vieillies 18 ans en bassin de stockage d'eau pour ainsi déterminer les mécanismes impliqués dans le vieillissement sur site / High Density PolyEthylene (HDPE) geomembranes (GMB) are used as basal liners in municipal solid waste (MSW) landfills. In spite of the good initial properties of the HDPE, his durability remains poorly known face to the chemical and biological strains of the MSW landfill leachate and the thermal and mechanical strains generated by the solid waste. The objective of this thesis is to contribute to the development of a non-empirical kinetic model for predicting HDPE GMB life cycle, that simultaneously takes into accounts the chemical and biological aging effects. For this purpose, we seek to determine on the one hand the extraction process parameters of the antioxidants present in the GMB, first step of the GMB aging, and on the other hand the kinetic parameters of the PE thermo-oxidation, second step of the GMB aging. This requires knowing and understanding the physico-chemical mechanisms involved in the PE aging in the particular conditions of MSW landfills. Using a multi-scale methodology (macro-micro) and multi-technique approach (FTIR; GPC-HT, DSC, tensile tests, …), we assess the impact of the accelerated aging on the chemical composition, on the macromolecular and crystalline structures and on the used properties of HDPE GMB and films. This study identified a relevant endlife criterion for assessing the GMB service lifetime: the embrittlement which corresponds to a critical molecular mass M'C of about 100 kg.mol-1. Coupling chemical oxidative degradation modelling of the polymer and biofilm growth kinetic modelling is proposed. In the last part, the same type of multi-scale approach has been applied to characterize the degradation of HDPE GMB aged 18 years in water storage basin in order to determine the mechanisms involved in natural aging