Geopolymers, a class of largely X-ray amorphous aluminosilicate binder materials, have been studied extensively over the past several decades, but largely from an empirical standpoint. The primary aim of this investigation has been to apply a more science-based approach to the study of geopolymers, including introducing a variety of mathematical modelling techniques to the field. The nanostructure of geopolymers is analysed via an extensive literature review, and conclusions regarding the presence and role of crystallinity within the geopolymer structure are drawn. Si/Al ordering within the tetrahedral aluminosilicate gel framework is described by a statistical thermodynamic model, which provides an accurate representation of the distribution of Si and Al sites within the framework as well as physically reasonable values for the energy penalty associated with ordering violation. Framework and extraframework structure within the geopolymer binder are also described by the pair distribution function (PDF) technique, whereby synchrotron X-ray scattering data are converted via a Fourier transform-based method into real-space structural data on an Ångstrom length scale. Real-space Rietveld analysis of geopolymers crystallised at high temperature is used to back-calculate and analyse the original geopolymer structure, and the primary change in very short-range structure from the as-synthesised geopolymer to the high-temperature crystalline product is observed to be a shift in the location of the extraframework charge-balancing cation.
| Identifer | oai:union.ndltd.org:ADTP/245153 |
| Creators | Provis, John Lloyd |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
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