the hydration products of a refractory calcium aluminate cement at intermediate temperatures
نویسندگان
چکیده
the major hydraulic phase in all the calcium aluminate cements including ciment fondue is ca (caal2o4). once hydrated, it starts to form the hexagonal crystals of cah10 and c2ah8 that depending on the time and temperature of hydration convert to the cubic crystals of c3ah6 and ah3. the nature, sequence, crystallinity and microstructure of hydrated phases of commercial refractory calcium aluminate cement were analyzed using differential scanning calorimetry (dsc), differential thermal analysis (dta), x-ray diffraction (xrd) and scanning electron microscopy (sem). the results showed that the formation of different hydrated phases was temperature dependent. at 28 oc, the hydration products at the beginning of hydration were a gel phase, c2ah8 and gibbsite, while cah10 also formed after four days of hydration, both c2ah8 and cah10 were converted to c3ah6 at latter ages. the rate of conversion of c2ah8 is dependent on the temperature and time of hydration at temperatures higher than 28 ºc and accelerates with increasing temperature, but still takes several weeks for completion at 36 ºc.
منابع مشابه
The Hydration Products of a Refractory Calcium Aluminate Cement at Intermediate Temperatures
The major hydraulic phase in all the calcium aluminate cements including ciment fondue is CA (CaAl2O4). Once hydrated, it starts to form the hexagonal crystals of CAH10 and C2AH8 that depending on the time and temperature of hydration convert to the cubic crystals of C3AH6 and AH3. The nature, sequence, ...
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calcium aluminates (ca) are the most important hydraulically setting cements used for preparing refractory castables, because they develop high strength at very early ages after placements. the anhydrous phases of this kind of cements are ca, ca2 and traces of c12a7 and alpha-alumina. the major hydraulic phase in all of the ca cements including ciment fondue is ca. once hydrated, it starts to ...
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Article history: Received 18 June 2014 Accepted 7 May 2015 Available online xxxx
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عنوان ژورنال:
iranian journal of chemistry and chemical engineering (ijcce)ناشر: iranian institute of research and development in chemical industries (irdci)-acecr
ISSN 1021-9986
دوره 26
شماره 3 2007
میزبانی شده توسط پلتفرم ابری doprax.com
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