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Strength Development in Phosphate‐Bonded Calcium Aluminate Cements
Author(s) -
Sugama Toshifumi,
Carciello Neal R.
Publication year - 1991
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.1151-2916.1991.tb04338.x
Subject(s) - anorthite , microstructure , aluminate , materials science , cement , phase (matter) , calcium pyrophosphate , cementitious , calcium , chemical engineering , amorphous solid , sintering , ammonium phosphate , mineralogy , composite material , metallurgy , chemistry , crystallography , fertilizer , organic chemistry , engineering
The chemical reaction at room temperature between calcium aluminate cement (CAC) and NH 4 H 2 PO 4 ‐based fertilizer solution causes the formation of ammonium calcium pyrophosphate (AmCPP) as an amorphous cementitious phase. This phase was responsible for the development of strength in rapid‐setting phosphate‐bonded cement (PBC) specimens. Hydrothermal treatment of PBC at 200°C led to phase transformations of AmCPP and CAC into crystalline hydroxyapatite as the major phase and anorthite as the minor one. The moderate growth of these interlocked crystals in the interspaces of amorphous phases played an important role in creating a dense microstructure, thereby conferring a very high strength to the PBC. In contrast, an excessive crystal growth, which caused the formation of porous microstructure, resulted in a reduction in strength.