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Early hydration and setting of Portland cement monitored by IR, SEM and Vicat techniques / Rikard Ylmén 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. 433–439 Titre : Early hydration and setting of Portland cement monitored by IR, SEM and Vicat techniques Type de document : texte imprimé Auteurs : Rikard Ylmén, Auteur ; Ulf Jäglid, Auteur ; Britt-Marie Steenari, Auteur Année de publication : 2009 Article en page(s) : pp. 433–439 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Hydration;  Calcium-silicate-hydrate  (C-S-H);Spectroscopy;  Cement  paste;  Portland  cement Résumé : Diffuse Reflectance Infrared DR-FTIR spectroscopy is employed to monitor chemical transformations in pastes of Portland limestone cement. To obtain a sufficient time resolution a freeze-dry procedure is used to instantaneously ceasing the hydration process. Rapid re-crystallization of sulphates is observed during the first 15 s, and appears to be complete after ~ 30 min. After ~ 60 min, spectroscopic signatures of polymerizing silica start to emerge. A hump at 970–1100 cm− 1 in conjunction with increasing intensity in the water bending mode region at 1500–1700 cm− 1 is indicative of the formation of Calcium Silicate Hydrate, C-S-H. Simultaneously with the development of the C-S-H signatures, a dip feature develops at 800–970 cm− 1, reflecting the dissolution of Alite, C3S. Setting times, 180 (initial) and 240 (final) minutes, are determined by the Vicat technique. Combining DR-FTIR, SEM and Vicat measurements it is concluded that the setting is caused by inter-particle coalescence of C-S-H. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609000465 [article] Early hydration and setting of Portland cement monitored by IR, SEM and Vicat techniques [texte imprimé] / Rikard Ylmén, Auteur ; Ulf Jäglid, Auteur ; Britt-Marie Steenari, Auteur . - 2009 . - pp. 433–439. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 5 (Mai 2009) . - pp. 433–439 Mots-clés : Hydration;  Calcium-silicate-hydrate  (C-S-H);Spectroscopy;  Cement  paste;  Portland  cement Résumé : Diffuse Reflectance Infrared DR-FTIR spectroscopy is employed to monitor chemical transformations in pastes of Portland limestone cement. To obtain a sufficient time resolution a freeze-dry procedure is used to instantaneously ceasing the hydration process. Rapid re-crystallization of sulphates is observed during the first 15 s, and appears to be complete after ~ 30 min. After ~ 60 min, spectroscopic signatures of polymerizing silica start to emerge. A hump at 970–1100 cm− 1 in conjunction with increasing intensity in the water bending mode region at 1500–1700 cm− 1 is indicative of the formation of Calcium Silicate Hydrate, C-S-H. Simultaneously with the development of the C-S-H signatures, a dip feature develops at 800–970 cm− 1, reflecting the dissolution of Alite, C3S. Setting times, 180 (initial) and 240 (final) minutes, are determined by the Vicat technique. Combining DR-FTIR, SEM and Vicat measurements it is concluded that the setting is caused by inter-particle coalescence of C-S-H. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609000465