Documents disponibles écrits par cet auteur

Early hydration of clinker–slag–metakaolin combination in steam curing conditions, relation with mechanical properties / F. Cassagnabèrea in Cement and concrete research, Vol. 39 N° 12 (Décembre 2009) 

Public ISBD [article]  in Cement and concrete research > Vol. 39 N° 12 (Décembre 2009) . - pp. 1164-1173 Titre : Early hydration of clinker–slag–metakaolin combination in steam curing conditions, relation with mechanical properties Type de document : texte imprimé Auteurs : F. Cassagnabèrea, Auteur ; M. Mouret, Auteur ; G. Escadeillas, Auteur Année de publication : 2010 Article en page(s) : pp. 1164-1173 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Cement/slag/MK  binder  ;  Steam  curing  ;  Early  age;  Hydration  product Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : High strength can be obtained at early ages for precast concrete elements by the use of CEMI 52.5R cement (OPC) and thermal treatment (steam curing). To compensate for the announced withdrawal of CEM I cements because of high CO2 emissions during their production and the ecotax that this will imply, one attractive alternative is the use of composed cements resulting from the combination of clinker with mineral admixtures. In steam curing conditions, previous studies have shown an increase in the compressive strength at one day of age for mortars incorporating an OPC/blast furnace slag (GGBS)/metakaolin (MK) combination, in comparison with mortars incorporating OPC only. The present study investigates the connection between the compressive strength, at one day of age, of steam cured mortars made with various binders and the hydration of these binders. The progress of the hydration was characterised by means of XRD, thermal and microprobe analyses. The results indicate that the increase in compressive strength when MK is incorporated (OPC/MK or OPC/MK/GGBS) can be explained by an increase in the amount of C-S-H, C-A-H, C-A-S-H phases, a decrease in the amount of CH and a change in the chemical nature of the matrix (decrease in C/S ratio). The decrease in compressive strength of OPC/slag-based material can be explained by a reduction in the amount of hydrated phases (particularly C-S-H) and compactness. These are promising results for precast concrete manufacturers who are concerned about preserving the environment. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609001859 [article] Early hydration of clinker–slag–metakaolin combination in steam curing conditions, relation with mechanical properties [texte imprimé] / F. Cassagnabèrea, Auteur ; M. Mouret, Auteur ; G. Escadeillas, Auteur . - 2010 . - pp. 1164-1173. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 12 (Décembre 2009) . - pp. 1164-1173 Mots-clés : Cement/slag/MK  binder  ;  Steam  curing  ;  Early  age;  Hydration  product Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : High strength can be obtained at early ages for precast concrete elements by the use of CEMI 52.5R cement (OPC) and thermal treatment (steam curing). To compensate for the announced withdrawal of CEM I cements because of high CO2 emissions during their production and the ecotax that this will imply, one attractive alternative is the use of composed cements resulting from the combination of clinker with mineral admixtures. In steam curing conditions, previous studies have shown an increase in the compressive strength at one day of age for mortars incorporating an OPC/blast furnace slag (GGBS)/metakaolin (MK) combination, in comparison with mortars incorporating OPC only. The present study investigates the connection between the compressive strength, at one day of age, of steam cured mortars made with various binders and the hydration of these binders. The progress of the hydration was characterised by means of XRD, thermal and microprobe analyses. The results indicate that the increase in compressive strength when MK is incorporated (OPC/MK or OPC/MK/GGBS) can be explained by an increase in the amount of C-S-H, C-A-H, C-A-S-H phases, a decrease in the amount of CH and a change in the chemical nature of the matrix (decrease in C/S ratio). The decrease in compressive strength of OPC/slag-based material can be explained by a reduction in the amount of hydrated phases (particularly C-S-H) and compactness. These are promising results for precast concrete manufacturers who are concerned about preserving the environment. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609001859

Effect of wetting-drying cycles on mortar samples affected by DEF / N. Leklou in European journal of environmental and civil engineering, Vol. 16 N° 5 (Mai 2012) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 16 N° 5 (Mai 2012) . - pp. 582-588 Titre : Effect of wetting-drying cycles on mortar samples affected by DEF Type de document : texte imprimé Auteurs : N. Leklou, Auteur ; J.-E. Aubert, Auteur ; G. Escadeillas, Auteur Année de publication : 2012 Article en page(s) : pp. 582-588 Note générale : Génie Civil Langues : Français (fre) Mots-clés : Wetting-drying  cycles  Microcracks  Scanning  electron  microscopy  (SEM)  Replica  Delayed  ettringite  formation  (DEF)  Expansion Résumé : This article, which deals with the effect of wetting–drying (W-D) cycles on materials affected by delayed ettringite formation (DEF), has two main objectives. The first is to observe whether W-D cycles pre-damage samples, by using the replica technique. Scanning electron microscopy (SEM) observations of replicas show that W-D cycles lead to microcracks in the samples. The second objective of the study is to observe whether the cycles are necessary for development of DEF or if they only accelerate DEF. A study of the expansion of the samples shows that cycles accelerate the appearance of expansion but they are not a prerequisite for triggering DEF. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.668017 [article] Effect of wetting-drying cycles on mortar samples affected by DEF [texte imprimé] / N. Leklou, Auteur ; J.-E. Aubert, Auteur ; G. Escadeillas, Auteur . - 2012 . - pp. 582-588. Génie Civil Langues : Français (fre) in European journal of environmental and civil engineering > Vol. 16 N° 5 (Mai 2012) . - pp. 582-588 Mots-clés : Wetting-drying  cycles  Microcracks  Scanning  electron  microscopy  (SEM)  Replica  Delayed  ettringite  formation  (DEF)  Expansion Résumé : This article, which deals with the effect of wetting–drying (W-D) cycles on materials affected by delayed ettringite formation (DEF), has two main objectives. The first is to observe whether W-D cycles pre-damage samples, by using the replica technique. Scanning electron microscopy (SEM) observations of replicas show that W-D cycles lead to microcracks in the samples. The second objective of the study is to observe whether the cycles are necessary for development of DEF or if they only accelerate DEF. A study of the expansion of the samples shows that cycles accelerate the appearance of expansion but they are not a prerequisite for triggering DEF. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.668017

Processing of electron microprobe data from the analysis of altered cementitious materials / A. Bertron in Cement and concrete research, Vol. 39 N° 10 (Octobre 2009) 

Public ISBD [article]  in Cement and concrete research > Vol. 39 N° 10 (Octobre 2009) . - pp. 929–935 Titre : Processing of electron microprobe data from the analysis of altered cementitious materials Type de document : texte imprimé Auteurs : A. Bertron, Auteur ; G. Escadeillas, Auteur ; P. de Parseval, Auteur Année de publication : 2009 Article en page(s) : pp. 929–935 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Cement  paste;  Degradation;  Electron  microprobe Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : The purpose of this paper is to present a method for processing electron microprobe data coming from the analysis of degraded cementitious materials. The application domain is that of cement matrices exposed to attack by aggressive media inducing the leaching of one or more chemical elements from the cement paste — typically attacked by neutral or acid aqueous environments. As raw data obtained from electron probe microanalysis (EPMA) come in the form of relative quantities of elements, the aim of the processing is to obtain the absolute variation of the specimen's chemical composition in the degraded zone and consequently to allow a better understanding of the degradation mechanisms by the aggressive environment under consideration. This method was designed for degraded specimens in which the porosity was not filled with resin before the EPMA. The method uses the titanium content of the cement matrix as a control, this element being stable during attack by neutral or acidic media. The method is described in detail using the example of the attack of cement pastes by a mix of several organic acids (notably acetic acid) at pH 4. The use of EPMA for sound and altered cement pastes is also validated. The application domain of the correction method is discussed. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609001410 [article] Processing of electron microprobe data from the analysis of altered cementitious materials [texte imprimé] / A. Bertron, Auteur ; G. Escadeillas, Auteur ; P. de Parseval, Auteur . - 2009 . - pp. 929–935. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 10 (Octobre 2009) . - pp. 929–935 Mots-clés : Cement  paste;  Degradation;  Electron  microprobe Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : The purpose of this paper is to present a method for processing electron microprobe data coming from the analysis of degraded cementitious materials. The application domain is that of cement matrices exposed to attack by aggressive media inducing the leaching of one or more chemical elements from the cement paste — typically attacked by neutral or acid aqueous environments. As raw data obtained from electron probe microanalysis (EPMA) come in the form of relative quantities of elements, the aim of the processing is to obtain the absolute variation of the specimen's chemical composition in the degraded zone and consequently to allow a better understanding of the degradation mechanisms by the aggressive environment under consideration. This method was designed for degraded specimens in which the porosity was not filled with resin before the EPMA. The method uses the titanium content of the cement matrix as a control, this element being stable during attack by neutral or acidic media. The method is described in detail using the example of the attack of cement pastes by a mix of several organic acids (notably acetic acid) at pH 4. The use of EPMA for sound and altered cement pastes is also validated. The application domain of the correction method is discussed. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609001410