WorldCat Identities

Davy, Catherine A. (1974-....).

Overview
Works: 22 works in 25 publications in 2 languages and 29 library holdings
Genres: Academic theses 
Roles: Author, Thesis advisor, Other, Opponent, Editor
Classifications: TD812, 620
Publication Timeline
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Most widely held works by Catherine A Davy
Self-sealing of fractures in argillaqceous formations in the context of geological disposal of radioactive waste : review and synthesis by Helmut Bock( Book )

1 edition published in 2010 in English and held by 3 WorldCat member libraries worldwide

After the clouds by Catherine A Davy( Book )

1 edition published in 1945 in English and held by 3 WorldCat member libraries worldwide

Etude expérimentale de la perméabilité du béton sous conditions thermiques et hydriques variables by Wei Chen( Book )

2 editions published in 2011 in French and held by 2 WorldCat member libraries worldwide

The main objective of this study is to evaluate the variable thermal and hydric effect, with fissuration effect on the hydraulic behaviour of two concretes. Many experimental tests (saturation and permeability measurements, uniaxial and triaxial compressions tests) were carried out in order to investigate the temperature and saturation influence on the behaviour hydraulic on sound and micro-cracked concrete. Moreover, an experimental device for permeability measurement on macro-cracked concrete was realized, it allows to study the behaviour of macro-cracked of concrete confined and subjected to dry gas flow or very moist air at different temperatures. Multiaxial mechanical tests are coupled to the permeability measurements of sound concrete and micro-cracked by freezing and thawing, which allow to measuring the permeability under deviatoric load-unload with the effect of pre-cracking under stress. We also effectuated a test of relative permeability of concrete as a function of water saturation, subjected to drying and resaturation, conditioning by the different relative humidity imposed
Impact de la fissuration sur les propriétés de rétention d'eau et de transport de gaz des géomatériaux : Application au stockage géologique des déchets radioactifs by Sofia M'jahad( Book )

2 editions published in 2012 in French and held by 2 WorldCat member libraries worldwide

In the context of geological disposal of radioactive waste, this work contributes to the characterization of the effect of diffuse damage on the water retention and gas transfer properties of concrete (CEM I and CEM V) selected by Andra, Callovo-Oxfordian argillite (host rock) and argillite / concrete interfaces. This study provides information on the concrete microstructure from Mercury porosimetry intrusion and water retention curves: each concrete has a distinct microstructure, CEM I concrete is characterized by a significant proportion of capillary pores while CEM V concrete has a large proportion of C-S-H pores. Several protocols have been developed in order to damage concrete. The damage reduces water retention capacity of CEM I concrete and increases its gas permeability. Indeed, gas breakthrough pressure decreases significantly for damaged concrete, and this regardless of the type of concrete. For argillite, the sample mass increases gradually at RH = 100%, which creates and increases damage in the material. This reduces its ability to retain water. Otherwise, water retention and gas transport properties of argillite are highly dependent of its initial water saturation, which is linked to its damage. Finally, we observed a clogging phenomenon at the argillite/concrete interfaces, which is first mechanical and then hydraulic (and probably chemical) after water injection. This reduces the gas breakthrough pressure interfaces
Comportement hydrique et poro-mécanique des bétons à hautes performances Andra : influence de la microstructure by Yao Zhang( Book )

2 editions published in 2014 in French and held by 2 WorldCat member libraries worldwide

This thesis focuses on water retention at high relative humidity (RH) (92-100%) and dessiccation shrinkage under moderate temperature (60-80°C) for two high performance concretes CEMI and CEMV (from Andra), in relation with their microstructure.To investigate the origins of the variations in water saturation degree Sw at high RH, both concretes are dried at RH=92, 98 and 100%, from the fully saturated state. For both concretes, sampling affects significantly Sw. For CEMI at 100%RH, sample size also affects Sw, due to surface drying (desorption); at 92 and 98%RH, CEMI is no longer sensitive to surface drying effects; it is sensitive to experimental conditions (RH, T). CEMV is affected by sample size whatever the RH, but not by experimental conditions.From 60°C drying temperature, the relationship between shrinkage and relative mass loss presents four distinct phases. CEMI concrete is dried at 65°C until phase 3 or 4, and then submitted to a coupled poro-mechanical and gas permeability test. For the same sample tested in phase 3 and then 4, a difference in solid skeleton incompressibility modulus Ks is measured, which is significantly lower than the differences in Ks due to sampling.With the Scanning Electron Microscope, the solid phases and morphology of both concretes are quantified. CEM I and CEM V comprise identical phases, even portlandite, yet CEM V concrete has some specific phases, owing to the addition of slag and fly ash. The C-S-H in CEM V have a lower C/S ratio than in CEM I. The (C/S) ratio remains similar when comparing between three different batches. Besides, millimetric pores vary significantly, owing to differences in manufacturing
Rétention d'eau et microstructure fine de l'argilite de Bure by Yang Song( )

1 edition published in 2014 in French and held by 1 WorldCat member library worldwide

In the context of deep underground storage of radioactive nuclear waste, it is important to identify the saturation hysteresis of the host rock, i.e. of Callovo-Oxfordian (COx) claystone, and its porosity and pore size distribution. Firstly, six different cycles of relative humidity are applied for saturation hysteresis, which is not observed in the cycles with low magnitude. Secondly, a new method is proposed for measuring porosity, which uses injection of gas to evaluate the pore volume. In contrast to porosity given by water adsorption, the gas injection method provides larger porosity values of around 5%. The gas injection method is also used to quantify the sorption-desorption isotherms of COx claystone, which are significantly different from those obtained by the gravimetric method, with a bigger pore volume accessible to gas in relative humidities < 43%. Finally, by Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM), we obtain 2D image stacks and 3D reconstructed pore volumes, by which porosity and pore size distribution are quantified down to 20nm, as well as pore orientation and anisotropy. At a higher resolution (below 1nm), Transmission Electron Microscopy (TEM) imaging reveals significant amounts of smaller pores (of a few nm) between clay aggregates
Etanchéité de l'interface argilite-bentonite re-saturée et soumise à une pression de gaz, dans le contexte du stockage profond de déchets radioactifs by JiangFeng Liu( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

In France, the deep underground nuclear waste repository consists of a natural barrier (in an argillaceous rock named argillite), associated to artificial barriers, including plugs of swelling clay (bentonite)-sand for tunnel sealing purposes. The main objective of this thesis is to assess the sealing efficiency of the bentonite-sand plug in contact with argillite, in presence of both water and gas pressures. To assess the sealing ability of partially water-saturated bentonite/sand plugs, their gas permeability is measured under varying confining pressure (up to 12MPa). It is observed that tightness to gas is achieved under confinement greater than 9MPafor saturation levels of at least 86-91%. We than assess the sealing efficiency of the bentonite-sand plug placed in a tube of argillite or of Plexiglas-aluminium (with a smooth or a rough interface). The presence of pressurized gas affects the effective swelling pressure at values Pgas from 4MPa. Continuous gas breakthrough of fully water-saturated bentonite-sand plugs is obtained for gas pressures on the order of full swelling pressure (7-8MPa), whenever the plug is applied along a smooth interface. Whenever a rough interface is used in contact with the bentonite-sand plug, a gas pressure significantly greater than its swelling pressure is needed for gas to pass continuously. Gas breakthrough tests show that the interface between plug/argillite or the argillite itself are two preferential pathways for gas migration, when the assembly is fully saturated
Transfert 2012 : propriétés de transfert des géomatériaux : Ecole centrale de Lille, 20-22 mars 2012 : actes du colloque by Transfert 2012( Book )

in French and held by 1 WorldCat member library worldwide

Comportement mécanique instantané des structures hybrides GFRP-béton by Alaa Koaik( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

Advanced composites are increasingly used in construction thanks to their indisputable advantages such as high strength to weight ratio and ease of implementation. However, their growth is hindered by a main weak point: low stiffness. Advanced composites risk instabilities under high loads which make it not possible to exploit their full potential. Considering flexural elements, one of the solutions proposed consists in associating the composite profiles with a reinforced concrete slab. The connection of both materials is either established by bolting, bonding or a combination of both techniques.In this study, 3 different connection modes were tested on structural elements with different spans. Previously, to characterize the mechanical behavior of the interface, 35 push out specimens having bolted or bonded connections were prepared and tested. In addition, all materials used were characterized.A composite beam (Pu1) and 8 hybrid beams (PB1-PB8) were tested under 3 points bending up to failure. The results are exploited to construct and test a hybrid footbridge. 7 push out series were tested and digital image correlation was used to analyze the behavior at the interface and measure the displacement fields to determine the slip. Concrete, GFRP, bolts, the adhesive and the concrete reinforcing steel bars were all characterized.The experimental data obtained from the tests is compared to calculation results obtained by a multi-layer beam model within service limit states and at ultimate ones. Besides, a 3D finite element model was developed to provide more accurate results.The results allow distinguishing 3 behavior modes relative to the 3 connection types: the connection by mechanical studs proves to be the most efficient so far. The measurements are also compared to the results obtained by a multi-layer beam model. The differences are acceptable except in the vicinity of the interface where the deformations can be affected by the cracking of the concrete which remains difficult to predict precisely. The 3D simulations present with an excellent agreement the experiments and explain some observations obtained
Effet du chauffage sur le comportement mécanique et poro-mécanique de matériaux cimentaires propriétés hydrauliques et changements morphologiques by Xiao-Ting Chen( Book )

1 edition published in 2009 in French and held by 1 WorldCat member library worldwide

This work investigates the effects of morphological changes of a cement-based material subjected to heat treatment (up to 400°C). For a model W/C=0.5 mortar, we have characterized experimentally hydraulic behaviour (gas permeability), mechanical behaviour (in uniaxial compression, hydrostatic compression with or without deviatoric stress) and poro-mechanical behaviour (incompressibility moduli Kb, Ks and Biot's coefficient b) after a heating/cooling cycle. We have also developed an original experiment aimed at quantifying the accessible pore space volume under hydrostatic compression. The creation of occluded porosity under high confinement is confirmed, which justifies the observed decrease of solid matrix rigidity Ks under high confinement. A gas retention phenomenon was identified under simultaneous thermal and hydrostatic loadings for mortar, and industrial concretes (provided by CERIB and ANDRA). A predictive thermo-elasto-plastic model with isotropic damage and a micro-mechanical approach, which represents micro-cracking, are coupled in order to analyze or predict the evolution of mechanical and poro-elastic properties after heat cycling
Etanchéité de l'interface argilite-bentonite re-saturée et soumise à une pression de gaz, dans le contexte du stockage profond de déchets radioactifs by JiangFeng Liu( Book )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

In France, the deep underground nuclear waste repository consists of a natural barrier (in an argillaceous rock named argillite), associated to artificial barriers, including plugs of swelling clay (bentonite)-sand for tunnel sealing purposes. The main objective of this thesis is to assess the sealing efficiency of the bentonite-sand plug in contact with argillite, in presence of both water and gas pressures. To assess the sealing ability of partially water-saturated bentonite/sand plugs, their gas permeability is measured under varying confining pressure (up to 12MPa). It is observed that tightness to gas is achieved under confinement greater than 9MPafor saturation levels of at least 86-91%. We than assess the sealing efficiency of the bentonite-sand plug placed in a tube of argillite or of Plexiglas-aluminium (with a smooth or a rough interface). The presence of pressurized gas affects the effective swelling pressure at values Pgas from 4MPa. Continuous gas breakthrough of fully water-saturated bentonite-sand plugs is obtained for gas pressures on the order of full swelling pressure (7-8MPa), whenever the plug is applied along a smooth interface. Whenever a rough interface is used in contact with the bentonite-sand plug, a gas pressure significantly greater than its swelling pressure is needed for gas to pass continuously. Gas breakthrough tests show that the interface between plug/argillite or the argillite itself are two preferential pathways for gas migration, when the assembly is fully saturated
Experimental and numerical study on thermo-mechanical behaviour of carbon fibre reinforced polymer and structures reinforced with CFRP by Phi Long Nguyen( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

Carbon fibre reinforced polymer (CFRP) is one of common solutions in repairing / reinforcing/strengthening/ retrofitting structures in civil engineering due to its advantages in mechanicalproperties, durability and workability. However, recent issues have raised concerns for fireperformance of CFRP and CFRP reinforced structures. Throughout the literature, there are severalinvestigations on the evolution of mechanical performance of CFRP and CFRP reinforced structuresduring or after exposing to different levels of temperature which are close to temperatures obtainedduring a fire. However, the results are scatter due to the diversity of materials used, the difference intest protocols, and limitation in test facility for elevated temperature use. Analytical and numericalstudies are also conducted with parametric investigation to observe, improve, and proposerecommendations for design guideline. Additionally, missing gap in experimental data has asignificant influence on the applicability of the available results.This research characterizes the behaviours of CFRPs and of concrete structure reinforced with CFRPmaterial under three separated conditions concerning elevated temperature and mechanical loadingthat are close to different cases of fire application. The experimental and numerical methods used inthis research are to further investigate the status of each material during the case studies. Particularly,residual test is used to study the mechanical performance of specimens cooled after exposing toelevated temperature respecting the evaluation of the remained behaviour of CFRP reinforcedstructures at post-fire situation for repairing/ retrofitting purpose. Two thermo-mechanical tests areused to study the mechanical performance of specimens at different elevated temperatures and theirthermal performance at different mechanical statuses respecting the fire situation for predicting anddesigning purpose. The two final cases focus on the influence of loading order on the results toconfirm the validity of experimental mechanical data obtained at different temperatures whenapplying for evaluating the fire performance of CFRP reinforced structure where mechanical effectsand then temperature effects are combined.In the first experimental part, 86 tests on two types of CFRP (one pre-fabricated in factory and onemanually fabricated in laboratory) were studied in the temperature range from 20°C to 712°C. Theperformance of CFRP material is generally reduced as the temperature increases. The thermomechanicaland residual ultimate strengths of P-CFRP gradually decrease from 20°C to 700°C, whileits Young's modulus varies less than 10% from 20°C to 400°C and then significantly decreases at600°C. The identified thermo-mechanical performance of CFRP was lower than its residualperformance, especially at temperature beyond 400°C. Furthermore, the elevated temperature andmechanical load are experimentally shown to be relevant and thus the loading order has a small effecton the material performance under thermo-mechanical conditions. A new analytical model, proposedfor the evolution of thermo-mechanical ultimate strength in function of temperature, has shown theability to fit with two studied CFRPs and with those tested under similar thermo-mechanical conditionin the literature [etc...]
Social isolation and the elderly by Catherine Davy( Book )

1 edition published in 1979 in English and held by 1 WorldCat member library worldwide

Contribution à la biomécanique de la régénération osseuse : modélisation, simulation et applications by Camille Spingarn( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

Cette thèse traite de la modélisation du remodelage osseux. Nous présentons tout d'abord un modèle général continu tenant compte de la réponse cellulaire à un stimulus mécanique. Ce modèle est appliqué à des géométries 2D et 3D macroscopiques afin de se rapprocher des problématiques réelles, ainsi que sur des géométries mésoscopiques d'os trabécullaires en 2D. Cependant la complexité du remodelage osseux ne permet pas d'avoir une approche unique de modélisation. Ainsi, dans un second temps, le cas particulier du remodelage osseux orthodontique est étudié. Un nouveau modèle spécifique est développé tenant compte de l'influence du ligament parodontal sur le remodelage osseux, et intégrant l'influence du taux d'oxygène qui contrôle les évolutions de densités cellulaires. Des données expérimentales in vitro sont extraites de la littérature et servent de données d'entrées du modèle développé afin d'obtenir l'évolution de la densité osseuse alentours d'une racine dentaire cylindrique en 3D
The elusive ettringite under the high-vacuum SEM - a reflection based on natural samples, the use of Monte Carlo modelling of EDS analyses and an extension to the ettringite group minerals( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

Ettringite, Ca6 Al2 (SO4)3 (OH)12 .26H2 O, or C6 A S ¯ 3 H32 as it is known in cement chemistry notation, is a major phase of interest in cement science as an hydration product and in polluted soil treatment since its structure can accommodate with many hazardous cations. Beyond those anthropogenic features, ettringite is first of all a naturally occurring mineral (although rare). An example of its behaviour under the scanning electron microscope and during energy dispersive spectroscopy (EDS) qualitative analysis is presented, based on the study of natural ettringite crystals from the N'Chwaning mine in South Africa. Monte Carlo modelling of the electron-matter interaction zone at various voltages is presented and confronted with actual, observed beam damage on crystals, which burst at the analysis spot. Finally, theoretical energy dispersive spectroscopy spectra for all the ettringite group minerals have been computed as well as Monte Carlo modelling of the electron-matter interaction zone. The knowledge of the estimation of the size of this zone may thus be helpful for the understanding of energy dispersive spectroscopy analysis in cement pastes or ettringite-remediated soils
The collapse behaviour of sugar aggregate by Catherine A Davy( Book )

1 edition published in 2002 in English and held by 1 WorldCat member library worldwide

Effet du chauffage sur le comportement mécanique et poro-mécanique de matériaux cimentaires : propriétés hydrauliques et changements morphologiques by Xiao-Ting Chen( )

1 edition published in 2009 in French and held by 1 WorldCat member library worldwide

This work investigates the effects of morphological changes of a cement-based material subjected to heat treatment (up to 400°C). For a model W/C=0.5 mortar, we have characterized experimentally hydraulic behaviour (gas permeability), mechanical behaviour (in uniaxial compression, hydrostatic compression with or without deviatoric stress) and poro-mechanical behaviour (incompressibility moduli Kb, Ks and Biot's coefficient b) after a heating/cooling cycle. We have also developed an original experiment aimed at quantifying the accessible pore space volume under hydrostatic compression. The creation of occluded porosity under high confinement is confirmed, which justifies the observed decrease of solid matrix rigidity Ks under high confinement. A gas retention phenomenon was identified under simultaneous thermal and hydrostatic loadings for mortar, and industrial concretes (provided by CERIB and ANDRA). A predictive thermo-elasto-plastic model with isotropic damage and a micro-mechanical approach, which represents micro-cracking, are coupled in order to analyze or predict the evolution of mechanical and poro-elastic properties after heat cycling
The collapse behaviour of a sugar aggregate by Catherine A Davy( Book )

1 edition published in 2002 in English and held by 1 WorldCat member library worldwide

Influences de la microstructure sur les propriétés mécaniques et hydrauliques des matériaux poreux cohérents by Catherine A Davy( Book )

1 edition published in 2010 in French and held by 1 WorldCat member library worldwide

Mes principaux travaux concernent les performances mécaniques et la durabilité des matériaux poreux cohérents, en relation avec leur microstructure. L'approche, qui s'intéresse aux phénomènes physiques responsables de l'état microstructural, est essentiellement expérimentale, et en lien avec différents contextes industriels. Les milieux poreux sont caractérisés par un couplage entre le squelette solide et le (ou les) fluide(s) présents dans leur réseau poreux, ce qui justifie l'évaluation de leurs performances par l'approche poro-mécanique [Coussy-2004]. La durabilité est évaluée par les capacités de transport advectif au travers du réseau poreux capillaire, c'est-à-dire par la perméabilité, dont la mesure au laboratoire peut aller jusqu'à des valeurs très faibles (10-21m2). Dans le contexte du stockage à long terme des déchets nucléaires radioactifs (confié à l'ANDRA par l'Etat français), la problématique est d'assurer une barrière étanche au sein de tunnels creusés dans une roche argileuse très peu perméable (l'argilite), consolidés par des bétons spécifiques et bouchés par des matériaux reconstitués (en particulier, l'argile gonflante qu'est la bentonite). J'ai contribué à la mise en évidence de la recicatrisation de l'argilite macro-fissurée (après excavation) sous l'effet d'une circulation d'eau (telle que celle présente in situ). Le transport advectif de gaz diminue également fortement sous l'effet d'un chargement mécanique de confinement (pression hydrostatique). Une cicatrisation similaire a été observée à l'interface entre argilite et bentonite, à partir d'une maquette reconstituée. Les pressions d'entrée de gaz au travers de l'argilite intacte ou recicatrisée, ou encore à l'interface argilite/bentonite recicatrisée, ont également été identifiées. Suite à cela, un modèle numérique thermo-hydro-poro-mécanique couplé a montré que le passage de gaz au travers de l'argilite intacte ne se fait pas de façon homogène, mais a plus à voir avec un phénomène de capillary fingering (digitation capillaire) au travers de passages potentiellement instables dans le réseau poreux. Certains grès sont des réservoirs de gaz naturel. Dans le cadre d'un partenariat GDF/Suez, il s'est agi de caractériser l'évolution des propriétés de transport advectif (perméabilité) de ces grès en fonction du confinement, du degré de saturation en eau et de la morphologie du réseau poreux, dans le but d'aider à améliorer l'extraction de gaz
 
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Audience level: 0.89 (from 0.43 for Social iso ... to 0.98 for Étude cri ...)

Alternative Names
Crestia, Catherine

Languages
French (16)

English (7)