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Alkaline Activation of Fly Ashes: NMR Study of the Reaction Products
Author(s) -
Palomo Ángel,
Alonso Santiago,
FernandezJiménez Ana,
Sobrados Isabel,
Sanz Jesús
Publication year - 2004
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.1551-2916.2004.01141.x
Subject(s) - magic angle spinning , curing (chemistry) , materials science , amorphous solid , fly ash , nuclear magnetic resonance spectroscopy , zeolite , magic angle , chemical engineering , nuclear chemistry , chemistry , polymer chemistry , composite material , organic chemistry , catalysis , engineering
Reaction products formed during alkaline activation, with 8 M N a OH solutions, of fly ashes have been characterized with 29 Si and 27 Al magic‐angle spinning nuclear magnetic resonance (MASNMR) spectroscopy. In particular, the influence of curing conditions (time and temperature of reaction) has been analyzed. NMR results show the formation of amorphous tecto‐silicates in which the amount of aluminum decreases in the two consecutive formed phases. The Si/Al ratio of zeolite precursor obtained at 85°C changes from 0.95 to 1.86 when curing time is increased from 5 h to 1 week. The evolution of the mechanical properties of prepared cements has also been discussed in terms of the phases formed and texture and morphology of samples.