Early hydration and setting of Portland cement monitored by IR, SEM and Vicat techniques
2009; Elsevier BV; Volume: 39; Issue: 5 Linguagem: Inglês
10.1016/j.cemconres.2009.01.017
ISSN1873-3948
AutoresRikard Ylmén, Ulf Jäglid, Britt‐Marie Steenari, Itai Panas,
Tópico(s)CO2 Sequestration and Geologic Interactions
ResumoDiffuse 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.
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