Documents disponibles écrits par cet auteur

Rheology of fiber reinforced cementitious materials / Laetitia Martinie in Cement and concrete research, Vol. 40 N° 2 (02 ex.) (Fevrier 2010) 

Public ISBD [article]  in Cement and concrete research > Vol. 40 N° 2 (02 ex.) (Fevrier 2010) . - pp. 226-234 Titre : Rheology of fiber reinforced cementitious materials : classification and prediction Type de document : texte imprimé Auteurs : Laetitia Martinie, Auteur ; Pierre Rossi, Auteur ; Nicolas Roussel, Auteur Année de publication : 2010 Article en page(s) : pp. 226-234 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Rheology  Mixture  proportioning  Fresh  concrete  Aggregate  Fiber  reinforcement Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : In this paper, the effect of rigid straight fibers on the yield stress of cementitious materials is studied. A simple model describing the contact network between rigid fibers inside the material is first derived from the physical phenomena involved in the case of spherical inclusions. As soon as this contact network becomes percolated, the yield stress of the mixture increases by several orders of magnitude. A prediction of the critical fiber amount leading to a very strong increase of the yield stress of any cement paste, mortar or concrete is then derived. A simple and helpful mix design criterion for Ultra High Performance Fiber Reinforced Concretes is finally proposed and applied to several mix proportions from literature. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TWG-4XDKCDW-1&_user=6 [...] [article] Rheology of fiber reinforced cementitious materials : classification and prediction [texte imprimé] / Laetitia Martinie, Auteur ; Pierre Rossi, Auteur ; Nicolas Roussel, Auteur . - 2010 . - pp. 226-234. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 40 N° 2 (02 ex.) (Fevrier 2010) . - pp. 226-234 Mots-clés : Rheology  Mixture  proportioning  Fresh  concrete  Aggregate  Fiber  reinforcement Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : In this paper, the effect of rigid straight fibers on the yield stress of cementitious materials is studied. A simple model describing the contact network between rigid fibers inside the material is first derived from the physical phenomena involved in the case of spherical inclusions. As soon as this contact network becomes percolated, the yield stress of the mixture increases by several orders of magnitude. A prediction of the critical fiber amount leading to a very strong increase of the yield stress of any cement paste, mortar or concrete is then derived. A simple and helpful mix design criterion for Ultra High Performance Fiber Reinforced Concretes is finally proposed and applied to several mix proportions from literature. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TWG-4XDKCDW-1&_user=6 [...]

Yield stress during setting of cement pastes from penetration tests / D. Lootens in Cement and concrete research, Vol. 39 N° 5 (Mai 2009) 

Public ISBD [article]  in Cement and concrete research > Vol. 39 N° 5 (Mai 2009) . - pp. 401–408 Titre : Yield stress during setting of cement pastes from penetration tests Type de document : texte imprimé Auteurs : D. Lootens, Auteur ; P. Jousset, Auteur ; Laetitia Martinie, Auteur Année de publication : 2009 Article en page(s) : pp. 401–408 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Rheology;  Yield  stress;  Penetration  tests Résumé : Measurements of highly visco-elastic media such as cementitious materials during hardening and setting are difficult with standard rheometers. That is why the transition between liquid and solid state of cement based materials is currently measured with standardized penetration tools such as Vicat needles, ball indentation, penetrometers and Hilti nail guns. The obtained results however depend on the measuring device and only give information in arbitrary units. Moreover, no existing theory correlates these tests together although empirical correlations between the Vicat, the Proctor or the Hilti nail gun measurements and more classical rheology can be found in literature. In the present paper, an overview of this type of test is presented. By examining in detail experimental results, elasto-plastic finite elements simulations and visco-plastic fluid dynamic simulations in the specific case of penetrometer test, it is demonstrated that there exists a systematic correlation between these test results and the yield stress of the tested material. Finally more general analytical relations for several penetration tests between yield stress of the tested material and experimental data are proposed. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609000271 [article] Yield stress during setting of cement pastes from penetration tests [texte imprimé] / D. Lootens, Auteur ; P. Jousset, Auteur ; Laetitia Martinie, Auteur . - 2009 . - pp. 401–408. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 5 (Mai 2009) . - pp. 401–408 Mots-clés : Rheology;  Yield  stress;  Penetration  tests Résumé : Measurements of highly visco-elastic media such as cementitious materials during hardening and setting are difficult with standard rheometers. That is why the transition between liquid and solid state of cement based materials is currently measured with standardized penetration tools such as Vicat needles, ball indentation, penetrometers and Hilti nail guns. The obtained results however depend on the measuring device and only give information in arbitrary units. Moreover, no existing theory correlates these tests together although empirical correlations between the Vicat, the Proctor or the Hilti nail gun measurements and more classical rheology can be found in literature. In the present paper, an overview of this type of test is presented. By examining in detail experimental results, elasto-plastic finite elements simulations and visco-plastic fluid dynamic simulations in the specific case of penetrometer test, it is demonstrated that there exists a systematic correlation between these test results and the yield stress of the tested material. Finally more general analytical relations for several penetration tests between yield stress of the tested material and experimental data are proposed. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609000271