Use of analytical techniques for the identification of the geopolymer reactions

Abstract

Geopolymers are systems of inorganic binders that can be used as eco-friendly sustainable binder alternate to Portland cement and thereby causing significant reduction of Green house gas emission in construction activities. Geopolymer is often produced by the reaction of alumino-Silicate precursor with alkaline solutions. Geopolymer has shown many excellent properties such as high early strength, good resistance against acid and sulfate attacks, and good performance in high temperature.The key mechanical strength giving components of geopolymeric binders are chemically complex and of multiphase nature since most of the precursor materials used are also structurally disordered, being either glassy or thermally disrupted layer structure. Hence, geopolymers pose the most significant outstanding problem of micro structural characterization. In the present study, industrial by products such as fly ash and GGBS are used as geopolymeric precursor materials and activated by combined solution of sodium silicate.The reactivity of fly ash, GGBS, development of strength and structure of Geopolymer under optimized reaction conditions were examined using different techniques such as X-Ray Fluorescence, X-Ray Diffraction, Scanning Electron Microscopy, 29Si and 27Al MAS -NMR spectroscopy and FT-IR Spectroscopy.The thermal stability of Geopolymer formed studied through thermal analysis TGA/DTA. The average mass loss was found to be of 8% after 1000 0C exposure which was significantly lower than Metakaolin 750 based Geopolymer reported in literature.