Re-use of waste glass in improving properties of metakaolin-based geopolymers: Mechanical and microstructure examinations

Alkaline fusion processed waste glass was re-used as a supplementary Si-source to improve the mechanical properties of Egyptian metakaolin-based geopolymers. Different alkaline silicate solutions having different SiO2/Na2O ratios were almost entirely prepared from waste glass fusion filtrates. Size of metakaolin and waste glass particles as well as early age curing temperature were governor factors on compressive strength. Structures were examined using XRD and FT-IR techniques, while microstructure was examined using SEM. Geopolymerization of as-received MK, at ambient temperature, recorded 28-day compressive strength of 35.36 MPa. Mechanical properties were improved via four consequential stages by lowering MK particle size to less than 38 mu m, loading of 3% undissolved waste glass, loading of 7% fused waste glass at SiO2/Na2O of 1.55, and early age curing at 40 degrees C recording 80.75, 82.36, 93.08 and 97.41 MPa, respectively. Geopolymerization reactions were evaluated spectroscopically. FT-IRs were deconvoluted by Gaussian equations. Quality evaluations of products were examined using SEM whence homogeneity, continuity and amount of un-reacted species. Na-geopolymers were observed along all studies temperatures with quality favorability to early age curing at 40 degrees C. (C) 2016 Elsevier Ltd. All rights reserved.