Analysis of cubic and orthorhombic C(3)A hydration in presence of gypsum and lime

Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) have been used to study the microstructural changes and phase development that take place during the hydration of cubic (pure) and orthorhombic (Na-doped) tricalcium aluminate (C(3)A) and gypsum in the absence and presence of lime. The results demonstrate that important differences occur in the hydration of each C(3)A polymorph and gypsum when no lime is added; orthorhombic C(3)A reacts faster with gypsum than the cubic phase, forming longer ettringite needles; however, the presence of lime slows down the formation of ettringite in the orthorhombic sample. Additional rheometric tests showed the possible effects on the setting time in these cementitious mixes.


Published in:
Journal Of Materials Science, 44, 2038-2045
Year:
2009
Publisher:
Springer Verlag
ISSN:
0022-2461
Keywords:
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 Record created 2010-11-30, last modified 2018-03-17

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