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The Effects of Prehydration on the Liquid Hydration of 3CaO·Al 2 O 3 with CaSO 4 ·2H 2 O
Author(s) -
BREVAL ELSE
Publication year - 1979
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1979.tb19087.x
Subject(s) - water vapor , ettringite , chemistry , relative humidity , hydration reaction , mineralogy , gypsum , liquid water , vapour pressure of water , dehydration , scanning electron microscope , inorganic chemistry , analytical chemistry (journal) , cement , materials science , organic chemistry , metallurgy , thermodynamics , portland cement , composite material , biochemistry , physics
Liquid hydration and water‐vapor hydration of 3CaO·Al 2 O 3 , were studied. Variable parameters were hydration time, temperature, relative humidity, and amount of gypsum. The hydration products (gel, ettringite, hexagonal hydrates, and 3CaO·Al 2 O 3 ·6H 2 O) were studied by electron microscopy, X‐ray diffractometry, and thermal analysis. A reaction scheme is proposed. The degree of water‐vapor hydration influenced the sequence of the subsequent liquid hydration which, however, was independent of the composition of the water‐vapor hydration products. Below a critical degree of water‐vapor hydration (≊3% combined water) the reaction with liquid water occurred as if no water‐vapor hydration had taken place. Above this value the reaction gave hydration products suggesting a change of the 3CaO·Al 2 O 3 reactivity. A possible correlation with the retardation of strength development of prehydrated cement is suggested.