Effect of fly ash/alkaline activator ratio on fly ash geopolymer artificial aggregate

Abstract

This research was conducted to study the effect of fly ash on alkaline activator ratio to the fly ash geopolymer artificial aggregate. The raw material used is fly ash, sodium silicate and sodium hydroxide. This research involves four different ratio of mix design which is 2.0, 2.5, 3.0 and 3.5 while ratio of NaOH/NaSi2O3 is constant at 2.5. In this study, the molarity of NaOH is fix at 12M. The characterization of fly ash was done by X-Ray Fluorescence (XRF). The properties of fly ash geopolymer artificial aggregate then characterized by Aggregate Impact Value (AIV), and its microstructure been observed by Scanning Electron Microscope (SEM). Results show that, the sample with Fly Ash/Alkaline Activator 3.0 give the lowest percentage of AIV (19.6%) which denotes a high performance of aggregate in concrete field and also contribute to high performance of concrete while ratio 2.0 gives the highest percentage of AIV (25.19%). The tested results indicated that the significant potential of fly ash geopolymer aggregate as an alternative artificial aggregate in construction materials field.