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The Effects of Temperature on the Local Structure of Metakaolin‐Based Geopolymer Binder: A Neutron Pair Distribution Function Investigation
Author(s) -
White Claire E.,
Provis John L.,
Proffen Thomas,
Van Deventer Jannie S. J.
Publication year - 2010
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.1551-2916.2010.03906.x
Subject(s) - metakaolin , geopolymer , leucite , aluminosilicate , materials science , sodium aluminosilicate , mullite , amorphous solid , neutron scattering , pair distribution function , chemical engineering , crystallization , composite material , mineralogy , neutron , crystallography , chemistry , fly ash , organic chemistry , ceramic , nuclear physics , mathematical analysis , physics , mathematics , engineering , catalysis
Neutron pair distribution function (PDF) analysis is utilized to advance the understanding of the local atomic structural characteristics of geopolymer binders derived from metakaolin, specifically the nature and amount of the water associated with these materials. Samples were heated in air to temperatures up to 1200°C, then analyzed ex situ by high momentum transfer neutron total scattering and PDF analysis. Water contained in large pores, along with water associated with hydration of potassium cations in the geopolymer framework structure, comprise the majority of water in this material. The remaining water is situated in small pores and as terminal hydroxyl groups attached to the Si–Al framework. The Si–Al framework structure undergoes only subtle rearrangement upon heating, but maintains a tetrahedral aluminosilicate framework environment. After crystallization with heating beyond 1000°C, the geopolymer gel is predominantly converted to leucite, with small amounts of amorphous mullite and glassy silica, which have never before been observed in heated geopolymers. This demonstrates the value of neutron PDF analysis to probe the local structure of these important geopolymeric materials.