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High‐Resolution X ‐ray Diffraction and Fluorescence Microscopy Characterization of Alkali‐Activated Slag‐Metakaolin Binders
Author(s) -
Bernal Susan A.,
Provis John L.,
Rose Volker,
Gutiérrez Ruby Mejía
Publication year - 2013
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/jace.12247
Subject(s) - metakaolin , aluminosilicate , calcium silicate hydrate , sodium aluminosilicate , chemical engineering , calcium aluminosilicate , sodalite , alkali metal , materials science , hydrate , zeolite , sodium silicate , mineralogy , chemistry , metallurgy , organic chemistry , cement , catalysis , engineering
The effect of the activator concentration on the structure of alkali silicate‐activated slag/metakaolin pastes is assessed through synchrotron radiation‐based X ‐ray techniques. As main reaction products, both calcium aluminosilicate hydrate ( C – A – S – H ) and sodium/calcium aluminosilicate hydrate [( C , N )– A – S – H ] type gels are formed in activated binders solely based on slag, along with the zeolitic products gismondine and garronite. In activated blended pastes, the inclusion of metakaolin in the binder hinders the formation of zeolite products, instead favoring the formation of a ( C , N )– A – S – H type gel consistent with the activation of metakaolin in the presence of high concentrations of Ca . The formation of the two distinct binding products is confirmed by high‐resolution X ‐ray fluorescence microscopy, where the “inner” products and the “outer” products have compositions consistent with ( C , N )– A – S – H and C – A – S – H type gels, respectively. These results provide important new insights into the gel chemistry and micro/nanostructure of blended alkali‐activated binder systems.