Recycling of Fly Ash into Geopolymer Concrete: Creation of a Database

Geopolymer concrete manufactured from several fly ash sources was evaluated. The analysis presented herein is based on the elemental chemical analysis, X-ray diffraction (XRD) and particle size distribution (PSD) of fly ash samples collected from 16 different coal-fired power generation units. Geopolymer paste and concrete specimens were prepared for each fly ash sample. Paste specimens were subjected to XRD while concrete was evaluated for setting time, compressive and flexural strengths, elastic modulus and Poisson´s ratio. A first order statistical analysis was undertaken to establish the ranges of values given by the chemical analysis, XRD and PSD of the various fly ash samples, and how they impact the behavior of the fresh mix as well as the mechanical characteristics of the resulting geopolymer concrete. This research is expected to serve as foundation for a more comprehensive analysis of fly ash-based geopolymer, including more fly ash samples and a thorough statistical analysis to determine correlations between fly ash characteristics and geopolymer concrete.