C. Jantzen—contributing editor
Evolution of Local Structure in Geopolymer Gels: An In Situ Neutron Pair Distribution Function Analysis
Article first published online: 6 APR 2011
© 2011 The American Ceramic Society
Journal of the American Ceramic Society
Volume 94, Issue 10, pages 3532–3539, October 2011
How to Cite
White, C. E., Provis, J. L., Llobet, A., Proffen, T. and van Deventer, J. S. J. (2011), Evolution of Local Structure in Geopolymer Gels: An In Situ Neutron Pair Distribution Function Analysis. Journal of the American Ceramic Society, 94: 3532–3539. doi: 10.1111/j.1551-2916.2011.04515.x
This work was funded in part by the Australian Research Council (ARC) (including some funding via the Particulate Fluids Processing Centre, a Special Research Centre of the ARC), and in part by a studentship paid to Claire White by the Centre for Sustainable Resource Processing via the Geopolymer Alliance. The HIPD instrument is located at Los Alamos Neutron Science Center, funded by DOE Office of Basic Energy Sciences. Los Alamos National Laboratory is operated by Los Alamos National Security LLC under DOE Contract DE-AC52-06NA25396.
- Issue published online: 4 OCT 2011
- Article first published online: 6 APR 2011
- Manuscript No. 28801. Received October 26, 2010; approved February 17, 2011.
Geopolymer cement is fast becoming a technologically important alternative to ceramics and traditional cement. However, the amorphous nature of the phases which participate in the molecular processes occurring during evolution of geopolymer gel has made nanoscale research challenging. Here, for the first time, the local structural correlations of metakaolin-based geopolymer gel have been elucidated using in situ neutron pair distribution function analysis, following the structural changes occurring due to dissolution and repolymerization molecular processes. Over the initial 17 h of reaction, the subtle structural changes observed predominantly relate to dissolution of the initial metakaolin precursor before formation of the gel. After 90 days the gel has formed and has transitioned from the initially formed geopolymer structure (gel 1) to a more stable and more ordered state (gel 2), via an increase in cross-linking within the geopolymer gel. Through analysis of precursor dissolution behavior in different activator solutions, the impact of morphology on the rate of dissolution has been postulated, with layered precursors (metakaolin) shown to behave differently than spherical precursors (fly ash) depending on the type of activator solution used. Hence, this investigation reveals the important structural changes occurring during synthesis of this new class of low-temperature ceramics.