Determination of the Reactivity Degree of Various Alkaline Solutions: A Chemometric Investigation

Abstract

Knowledge of alkaline silicate solutions is crucial in order to optimize geopolymer properties. Geopolymers are new binders resulting from the activation of an aluminosilicate by an alkaline solution. It is well established that the solution reactivity strongly affects the geopolymerization and therefore the geopolymer working properties. As a consequence, an evaluation of the reactivity degree of alkaline silicate solutions prior synthesis is of the utmost interest. However, the determination of the solution reactivity is currently tedious, and for geopolymer commercialization, it would be necessary to find an easy way to determine it. Therefore, Raman spectroscopy, combined with chemometric techniques, is proposed as a solution to easily determine the alkaline silicate solution reactivity. To conduct this investigation, 65 silicate solutions were characterized by Raman spectroscopy, and reference values of their reactivity degree were determined. Finally, principal component analysis and partial least squares regression were performed to build a statistical model able to predict the alkaline silicate solution reactivity from Raman spectra.

Why geopolymers and alkali‐activated materials are key components of a sustainable world: A perspective contribution

“…When mixed under high shear with water glass solution (e.g. of composition M 2 O•2SiO 2 •11H 2 O), it undergoes dissolution, polycondensation, and precipitation to form a geopolymer solid where the silicate and aluminate tetrahedra are corner shared [8][9][10][11][12][13][14][15][16][17] with very recent 18 evidence of a few percentages of nonframework Al species acting in charge-balancing roles and, finally, that not all tetrahedra have four common corners.…”

Structural study of the effect of mineral additives on the transparency, stability, and aging of silicate gels

“…Raman spectroscopy allows highlighting the depolymerization of the different species as a function of the content of alkaline ions [20,21] . Raman spectroscopy was also combined to chemometric techniques to easily determine the alkaline silicate solution depolymerization degree and therefore reactivity through the chains to rings ratio [22] . It was also used to study the Q n speciation in binary potassium silicate melts [23] .…”