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Carbonation of CH and C–S–H in composite cement pastes containing high amounts of BFS / Paulo H.R. Borges 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. 284-292 Titre : Carbonation of CH and C–S–H in composite cement pastes containing high amounts of BFS Type de document : texte imprimé Auteurs : Paulo H.R. Borges, Auteur ; Juliana O. Costa, Auteur ; Neil B. Milestone, Auteur Année de publication : 2010 Article en page(s) : pp. 284-292 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Calcium–silicate–hydrate  (C–S–H)  Thermal  analysis  Carbonation  Granulated  blast-furnace  slag Résumé : 3:1 BFS:OPC, 9:1 BFS:OPC and 9:1 alkali activated BFS:OPC pastes cured at 20 °C and 60 °C for 90 days were submitted to accelerated carbonation under 5% CO2, 60% relative humidity and 25 ± 5 °C for 21 days. TGA/DTG was used to quantify the amounts of carbonates formed from calcium hydroxide (CH) and calcium silicate hydrate (C–S–H), based on the CH and carbonate contents before and after carbonation. Apparent dry density, apparent porosity and gas permeability were measured before and after accelerated carbonation testing, and the phenolphthalein method used to determine the accelerated carbonation rate. The results showed that samples cured at elevated temperature, i.e. 60 °C, were initially less porous and, therefore, had decreased levels of both total carbonation and C–S–H carbonation. In addition, the carbonation of C–S–H was significantly higher in pastes that contained less CH before carbonation. In the activated 9:1 BFS:OPC, the carbonation of C–S–H was extensive, despite a lower carbonation rate than the analogous non-activated system. In the particular case of activated 9:1 BFS:OPC, a shift in the DTG decarbonation pattern was observed and XRD showed that aragonite was present as one of the calcium carbonate polymorphs. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TWG-4XRBH3Y-1&_user=6 [...] [article] Carbonation of CH and C–S–H in composite cement pastes containing high amounts of BFS [texte imprimé] / Paulo H.R. Borges, Auteur ; Juliana O. Costa, Auteur ; Neil B. Milestone, Auteur . - 2010 . - pp. 284-292. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 40 N° 2 (02 ex.) (Fevrier 2010) . - pp. 284-292 Mots-clés : Calcium–silicate–hydrate  (C–S–H)  Thermal  analysis  Carbonation  Granulated  blast-furnace  slag Résumé : 3:1 BFS:OPC, 9:1 BFS:OPC and 9:1 alkali activated BFS:OPC pastes cured at 20 °C and 60 °C for 90 days were submitted to accelerated carbonation under 5% CO2, 60% relative humidity and 25 ± 5 °C for 21 days. TGA/DTG was used to quantify the amounts of carbonates formed from calcium hydroxide (CH) and calcium silicate hydrate (C–S–H), based on the CH and carbonate contents before and after carbonation. Apparent dry density, apparent porosity and gas permeability were measured before and after accelerated carbonation testing, and the phenolphthalein method used to determine the accelerated carbonation rate. The results showed that samples cured at elevated temperature, i.e. 60 °C, were initially less porous and, therefore, had decreased levels of both total carbonation and C–S–H carbonation. In addition, the carbonation of C–S–H was significantly higher in pastes that contained less CH before carbonation. In the activated 9:1 BFS:OPC, the carbonation of C–S–H was extensive, despite a lower carbonation rate than the analogous non-activated system. In the particular case of activated 9:1 BFS:OPC, a shift in the DTG decarbonation pattern was observed and XRD showed that aragonite was present as one of the calcium carbonate polymorphs. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TWG-4XRBH3Y-1&_user=6 [...]