Comportement et simulation des matériaux cimentaires en environnement agressifs

Comportement et simulation des matériaux cimentaires en environnement agressifs PDF Author: Siham Kamali
Publisher:
ISBN: 9782110940643
Category :
Languages : fr
Pages : 214

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Comportement et simulation des matériaux cimentaires en environnement agressifs

Comportement et simulation des matériaux cimentaires en environnement agressifs PDF Author: Siham Kamali
Publisher:
ISBN: 9782110940643
Category :
Languages : fr
Pages : 214

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Book Description


Comportement des matériaux cimentaires dans un coffrage

Comportement des matériaux cimentaires dans un coffrage PDF Author: Ny Riana Andriamanantsilavo
Publisher:
ISBN:
Category :
Languages : fr
Pages : 131

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Book Description
Une campagne expérimentale axée sur l'étude du comportement hydrodynamique des pâtes de ciment et des bétons au jeune âge en fonction de la hauteur de matériau mis en oeuvre dans un coffrage est présentée et constitue la première phase de ce travail de recherche. Les expérimentations ont nécessité le développement de capteurs de mesure de la pression interstitielle et de la pression latérale totale. Les paramètres suivants sont analysés : teneur en eau du mélange, concentration granulaire dans un mélange, présence de la vibration, hauteur de matériau mis en oeuvre. Dans une deuxième phase, nous nous intéressons à la simulation de l'évolution des pressions dans un coffrage. La démarche adoptée repose sur une modélisation de la cinétique d'évolution de l'état de l'eau dans un milieu poreux non saturé. Nos investigations nous ont conduits à adapter l'équation de Richards à notre problématique.

Modélisation par éléments discrets du comportement des matériaux cimentaires sous impact sévère

Modélisation par éléments discrets du comportement des matériaux cimentaires sous impact sévère PDF Author: Hicham Benniou
Publisher:
ISBN:
Category :
Languages : fr
Pages : 0

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Book Description
Ce travail de thèse concerne la modélisation du béton et des ouvrages en béton soumis à des sollicitations allant du quasi statique à la dynamique rapide, tout en prenant en compte de la présence d'eau libre dans les pores du béton. L'objectif est la mise au point d'un outil prévisionnel de simulation capable de décrire le comportement du béton et des structures en béton, en tenant compte des effets du taux de saturation. Le choix des Éléments Discrets pour cette modélisation est justifié par les phénomènes discontinus qui apparaissent dans le béton, tel que la fissuration, la fragmentation ou l'écaillage. Les Éléments Discrets permettent de reproduire de manière fiable et efficace le comportement discontinu local ainsi que la réponse globale de la structure.La première partie de ce travail concerne la simulation d'essais quasi-statiques sous sollicitations uniaxiales et triaxiales fortement confinées, avec la prise en compte du phénomène de compaction. Les effets de l'eau libre contenue dans les porosités sont pris en compte par l'introduction d'une dépendance entre le taux de saturation en eau et la déformation inélastique. La procédure d'identification des paramètres du modèle est présentée. Enfin, le modèle est validé en reproduisant le comportement quasi-statique du béton par différents essais. La deuxième partie de ce travail est consacrée au comportement dynamique du béton. L'objectif est d'étendre la validation du modèle en simulant des essais d'impacts. Les effets de vitesse sont pris en comptes et des simulations d'impact sur des dalles en béton de différentes épaisseurs sont effectuées. Les résultats obtenus sont en bonne concordance avec les résultats expérimentaux.

Performance of Cement-Based Materials in Aggressive Aqueous Environments

Performance of Cement-Based Materials in Aggressive Aqueous Environments PDF Author: Mark Alexander
Publisher: Springer Science & Business Media
ISBN: 9400754132
Category : Technology & Engineering
Languages : en
Pages : 471

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Book Description
Concrete and cement-based materials must operate in increasingly aggressive aqueous environments, which may be either natural or industrial. These materials may suffer degradation in which ion addition and/or ion exchange reactions occur, leading to a breakdown of the matrix microstructure and consequent weakening. Sometimes this degradation can be extremely rapid and serious such as in acidic environments, while in other cases degradation occurs over long periods. Consequences of material failure are usually severe – adversely affecting the health and well-being of human communities and disturbing ecological balances. There are also large direct costs of maintaining and replacing deteriorated infrastructure and indirect costs from loss of production during maintenance work, which place a great burden on society. The focus of this book is on addressing issues concerning performance of cement-based materials in aggressive aqueous environments , by way of this State-of-the-Art Report. The book represents the work of many well-known and respected authors who contributed chapters or parts of chapters. Four main themes were addressed: I. Nature and kinetics of degradation and deterioration mechanisms of cement-based materials in aggressive aqueous environments, II. Modelling of deterioration in such environments, III. Test methods to assess performance of cement-based materials in such environments, and which can be used to characterise and rate relative performance and inform long term predictions, IV. Engineering implications and consequences of deterioration in aggressive aqueous environments, and engineering approaches to the problem.

Durabilité des matériaux cimentaires

Durabilité des matériaux cimentaires PDF Author: Emmanuel Guillon
Publisher:
ISBN: 9782110951007
Category :
Languages : fr
Pages : 154

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Book Description
Les performances des matériaux de construction à matrice cimentaire proviennent principalement du ciment hydraté. Grâce à l'expérimentation et à la modélisation ces matériaux ont pu être adaptés à certains environnements chimiquement agressifs. Nous proposons une nouvelle approche basée sur les transports réactifs, applicable à tout solution agressive externe. L'évolution des minéraux de la matrice cimentaire, par dissolutions ou précipitations, est mise en relation avec celle de la solution interstitielle, elle même reliée aux échanges ioniques avec l'extérieur. Les dégradations chimiques modifient la microstructure du matériau, qui est modélisée par des images digitalisées. Notre approche a été validée sur trois matériaux différents, dans trois environnements distincts. Un modèle mécanique aux éléments-finis, complémentaire, caractérise l'évolution du module de Young résiduel du matériau dégradé en utilisant la représentation digitalisée de la microstructure.

Autogenous Shrinkage of Concrete

Autogenous Shrinkage of Concrete PDF Author: Ei-ichi Tazawa
Publisher: CRC Press
ISBN: 9780419238904
Category : Architecture
Languages : en
Pages : 432

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Book Description
This book forms the proceedings of a workshop held in Hiroshima in June 1998 and derive from the work of a Technical Committee of the Japan Concrete Institute. Topics include test and prediction methods, the science of autogenous shrinkage, strain and stress, and consequent design concerns.

Self-Compacting Concrete

Self-Compacting Concrete PDF Author: Ahmed Loukili
Publisher: John Wiley & Sons
ISBN: 1118601963
Category : Technology & Engineering
Languages : en
Pages : 251

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Book Description
Self-Compacting Concrete (SCC) is a relatively new building material. Nowadays, its use is progressively changing the method of concrete placement on building sites. However, the successful use of SCC requires a good understanding of the behavior of this material, which is vastly different from traditional concrete. For this purpose, a lot of research has been conducted on this area all over the world since 10 years. Intended for both practitioners and scientists, this book provides research results from the rheological behavior of fresh concrete to durability.

Practical Residual Stress Measurement Methods

Practical Residual Stress Measurement Methods PDF Author: Gary S. Schajer
Publisher: John Wiley & Sons
ISBN: 1118342372
Category : Technology & Engineering
Languages : en
Pages : 328

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Book Description
An introductory and intermediate level handbook written in pragmatic style to explain residual stresses and to provide straightforward guidance about practical measurement methods. Residual stresses play major roles in engineering structures, with highly beneficial effects when designed well, and catastrophic effects when ignored. With ever-increasing concern for product performance and reliability, there is an urgent need for a renewed assessment of traditional and modern measurement techniques. Success critically depends on being able to make the most practical and effective choice of measurement method for a given application. Practical Residual Stress Measurement Methods provides the reader with the information needed to understand key residual stress concepts and to make informed technical decisions about optimal choice of measurement technique. Each chapter, written by invited specialists, follows a focused and pragmatic format, with subsections describing the measurement principle, residual stress evaluation, practical measurement procedures, example applications, references and further reading. The chapter authors represent both international academia and industry. Each of them brings to their writing substantial hands-on experience and expertise in their chosen field. Fully illustrated throughout, the book provides a much-needed practical approach to residual stress measurements. The material presented is essential reading for industrial practitioners, academic researchers and interested students. Key features: • Presents an overview of the principal residual stress measurement methods, both destructive and non-destructive, with coverage of new techniques and modern enhancements of established techniques • Includes stand-alone chapters, each with its own figures, tables and list of references, and written by an invited team of international specialists

Pore Structure of Cement-Based Materials

Pore Structure of Cement-Based Materials PDF Author: Kalliopi K. Aligizaki
Publisher: CRC Press
ISBN: 9780419228004
Category : Science
Languages : en
Pages : 442

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Book Description
Pore Structure of Cement-Based Materials provides a thorough treatment of the experimental techniques used to characterize the pore structure of materials. The text presents the principles and practical applications of the techniques used, organized in an easy-to-follow and uncomplicated manner, providing the theoretical background, the way to analyze experimental data, and the factors affecting the results. The book is the single comprehensive source of the techniques most commonly used for pore structure analysis, covering simple techniques like mercury intrusion porosimetry and water absorption, to the more sophisticated small-angle scattering and nuclear magnetic resonance. The book is an essential reference text for researchers, users, and students in materials science, applied physics, and civil engineering, who seek a deep understanding of the principles and limitations of the techniques used for pore structure analysis of cement-based materials.

Microporomechanics

Microporomechanics PDF Author: Luc Dormieux
Publisher: John Wiley & Sons
ISBN: 0470031999
Category : Science
Languages : en
Pages : 344

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Book Description
Intended as a first introduction to the micromechanics of porous media, this book entitled “Microporomechanics” deals with the mechanics and physics of multiphase porous materials at nano and micro scales. It is composed of a logical and didactic build up from fundamental concepts to state-of-the-art theories. It features four parts: following a brief introduction to the mathematical rules for upscaling operations, the first part deals with the homogenization of transport properties of porous media within the context of asymptotic expansion techniques. The second part deals with linear microporomechanics, and introduces linear mean-field theories based on the concept of a representative elementary volume for the homogenization of poroelastic properties of porous materials. The third part is devoted to Eshelby’s problem of ellipsoidal inclusions, on which much of the micromechanics techniques are based, and illustrates its application to linear diffusion and microporoelasticity. Finally, the fourth part extends the analysis to microporo-in-elasticity, that is the nonlinear homogenization of a large range of frequently encountered porous material behaviors, namely, strength homogenization, nonsaturated microporomechanics, microporoplasticity and microporofracture and microporodamage theory.