Geopolymer depolymerization index

Glass-like behavior of the geopolymer samples have been investigated by determination of the influence of the geopolymerization reaction equilibrium on the types of SiO4 tetrahedra polymerization present. In order to manipulate geopolymerization reaction equilibrium, aluminum and sodium content in the samples was varied. Micro Raman spectroscopy has been used in order to analyze the dominant structure of the samples by evaluating the results against corresponding analysis of a related silicate material, both crystalline and amorphous, in order to determine the types and intensity of the SiO4 polymerization present. The obtained results suggest silicate glass-like behavior of investigated material concerning SiO4 tetrahedra depolymerization. The results also suggest the possibility of aluminum free geopolymerization what implies behavior other than that proposed by definition of geopolymers. Based on the obtained results, concept and calculation of the Geopolymer Depolymerization Index as an approximate measure of the content of the depolymerized SiO4 tetrahedra in the fly ash geopolymers using Raman spectroscopy have been proposed. (C) 2016 Elsevier B.V. All rights reserved.