Preparation of geopolymer precursors by sol–gel method and their characterization

The effects of SiO2/Na2O molar ratio on the characteristics of alkali-activated waste catalyst–metakaolin based geopolymers

“…Geopolymers exhibit 3D aluminosilicate gel structures and are formed through the alkaline activation of solid aluminosilicate-containing precursors, and the CO 2 footprint of geopolymers is lower than that of traditional Portland cement [2][3][4][5]. Fernández-Jiménez et al and Rees et al investigated the geopolymerization mechanism during the NaOH activation of fly ash by using scanning and transmission electron microscopy (SEM and TEM) and attenuated total reflectance-Fourier transform infrared spectroscopy, respectively.…”

Thermally treated clay sediments as geopolymer source material

“…10b), but the spectrum still showed a remarkable resonance at 3 ppm. Spectra of heat-treated sample exhibit a very small peak around 35 ppm that reflects penta-coordinated Al (AlV) of metakaolin: this intermediate is common when kaolinite transforms to metakaolinite (Rocha and Klinowski, 1990;Zheng et al, 2009). However, the Al IV /Al VI increased significantly with the addition of the activating solutions (Fig.…”

Effect of synthesis parameters on the performance of alkali-activated non-conformant EN 450 pulverised fuel ash

“…This class of binders are obtained from the reaction between alumina-silicate feedstock and concentrated solutions of alkali hydroxides [2,3], silicates [4], sulphates [5], carbonates [6] or combinations thereof [7,8]. An overview of the mechanism responsible for the transformation of the initial constituent materials into a binder has been extensively reported [9,10].…”