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Mechanical Property Evolution during Autoclaving Process of Aerated Concrete Using Slag: I, Tobermorite Formation and Reaction Behavior of Slag
Author(s) -
Isu Norifumi,
Sasaki Kaori,
Ishida Hideki,
Mitsuda Takeshi
Publication year - 1994
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.1151-2916.1994.tb07101.x
Subject(s) - tobermorite , materials science , slag (welding) , crystallinity , ground granulated blast furnace slag , metallurgy , diffusion , solubility , gehlenite , chemical engineering , mineralogy , composite material , chemistry , phase (matter) , physics , organic chemistry , cement , engineering , thermodynamics
The chemical reactions in the formation of autoclaved aerated concrete (AAC) block were investigated. The samples were prepared using blast furnace slag at 180°C under saturated steam pressures for various times from 1 to 128 h. Autoclaving for 1 h yielded 1.1‐nm tobermorite with higher Al substitution and lower Ca/(Al + Si) ratio than that made without slag, due to the high solubility of the slag during the initial stage of reaction. This suggests that the utilization of slag has an advantage of reducing processing time. On further reaction, the crystallinity of the tobermorite increases and its Ca/(Al + Si) ratio decreases, becoming constant after 64 h. After a long period of autoclaving. thick reaction rims are formed around unreacted slag particles, interrupting the diffusion of Ca from slag to matrix.