Documents disponibles écrits par cet auteur

Accelerated leaching of cementitious materials using ammonium nitrate (6M) / Stéphane Poyet in European journal of environmental and civil engineering, Vol. 16 N° 3-4 (Mars/Avril 2012) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 16 N° 3-4 (Mars/Avril 2012) . - pp. 336-351 Titre : Accelerated leaching of cementitious materials using ammonium nitrate (6M) : Influence of test conditions Type de document : texte imprimé Auteurs : Stéphane Poyet, Auteur ; Patrick Le Bescop, Auteur ; Magalie Pierre, Auteur Année de publication : 2012 Article en page(s) : pp. 336-351 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Cementitious  materials  Accelerated  degradation  Ammonium  nitrate  Protocol  influence Résumé : We have focused on the test conditions influence on accelerated degradation of cementitious materials using ammonium nitrate. PH-buffering and renewal of the leaching solution were studied. PH-buffering appeared not to be very important when the renewal pH remains under eight. Renewal appeared to be the most influential feature. Its absence leads to calcium accumulation in the leaching solution inducing aggressiveness fall. Degradation is then less marked in terms of depth, flux and mineralogy. The resulting porosity increase is also smaller. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667712 [article] Accelerated leaching of cementitious materials using ammonium nitrate (6M) : Influence of test conditions [texte imprimé] / Stéphane Poyet, Auteur ; Patrick Le Bescop, Auteur ; Magalie Pierre, Auteur . - 2012 . - pp. 336-351. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 16 N° 3-4 (Mars/Avril 2012) . - pp. 336-351 Mots-clés : Cementitious  materials  Accelerated  degradation  Ammonium  nitrate  Protocol  influence Résumé : We have focused on the test conditions influence on accelerated degradation of cementitious materials using ammonium nitrate. PH-buffering and renewal of the leaching solution were studied. PH-buffering appeared not to be very important when the renewal pH remains under eight. Renewal appeared to be the most influential feature. Its absence leads to calcium accumulation in the leaching solution inducing aggressiveness fall. Degradation is then less marked in terms of depth, flux and mineralogy. The resulting porosity increase is also smaller. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667712

Hydration of calcium sulfoaluminate cement by a ZnCl2 solution: Investigation at early age / Stéphane Bergera 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. 1180-1187 Titre : Hydration of calcium sulfoaluminate cement by a ZnCl2 solution: Investigation at early age Type de document : texte imprimé Auteurs : Stéphane Bergera, Auteur ; Céline Cau Dit Coumes, Auteur ; Patrick Le Bescop, Auteur Année de publication : 2010 Article en page(s) : pp. 1180-1187 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Sulfialuminate;  Hydration;  Zinc;  Waste  management;  Calorimetry Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : Hydration of calcium sulfoaluminate cement at early age was investigated as a function of the gypsum content of the binder, the thermal history of the material, and the ZnCl2 concentration in the mixing solution. Early hydration was strongly accelerated by the presence of gypsum, but lower percentages of reaction were reached after 24 h. The slowing down effect induced by ZnCl2, even at a concentration as high as 0.5 mol/L, was moderated compared to OPC but had a greater intensity in the absence of gypsum. Unlike what would have been expected for Portland cement, it was shown that the delay of a gypsum-free calcium sulfoaluminate cement resulted from the strong retardation caused by chloride anions, which was partly compensated by the accelerating effect of Zn2+ cations. The mineralogical observations revealed the precipitation of chloro–AFm phases such as Friedel's and Kuzel's salts, but no crystallized zinc-containing phases could be identified by XRD. The thermal history of the samples proved to be a key parameter. Applying a thermal cycle which reproduced the temperature rise and decrease occurring in a massive mortar block accelerated the rate of hydration and mainly modified the proportion of AFt versus AFm hydrates, especially when the binder had a gypsum content below 20%. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S000888460900204X [article] Hydration of calcium sulfoaluminate cement by a ZnCl2 solution: Investigation at early age [texte imprimé] / Stéphane Bergera, Auteur ; Céline Cau Dit Coumes, Auteur ; Patrick Le Bescop, Auteur . - 2010 . - pp. 1180-1187. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 12 (Décembre 2009) . - pp. 1180-1187 Mots-clés : Sulfialuminate;  Hydration;  Zinc;  Waste  management;  Calorimetry Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : Hydration of calcium sulfoaluminate cement at early age was investigated as a function of the gypsum content of the binder, the thermal history of the material, and the ZnCl2 concentration in the mixing solution. Early hydration was strongly accelerated by the presence of gypsum, but lower percentages of reaction were reached after 24 h. The slowing down effect induced by ZnCl2, even at a concentration as high as 0.5 mol/L, was moderated compared to OPC but had a greater intensity in the absence of gypsum. Unlike what would have been expected for Portland cement, it was shown that the delay of a gypsum-free calcium sulfoaluminate cement resulted from the strong retardation caused by chloride anions, which was partly compensated by the accelerating effect of Zn2+ cations. The mineralogical observations revealed the precipitation of chloro–AFm phases such as Friedel's and Kuzel's salts, but no crystallized zinc-containing phases could be identified by XRD. The thermal history of the samples proved to be a key parameter. Applying a thermal cycle which reproduced the temperature rise and decrease occurring in a massive mortar block accelerated the rate of hydration and mainly modified the proportion of AFt versus AFm hydrates, especially when the binder had a gypsum content below 20%. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S000888460900204X