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

• Published in: Construction & building materials 2017-02, Vol.132, p.543-555
• Main Authors: Naggar, Mohamed R. El, Dessouky, Mohamed I. El
• Format: Article
• Language: English
• Subjects: Analysis; Fusion processing; Geopolymer; Mechanical properties; Metakaolin; Microstructure-final; Nuclear energy; Portland cement; Radioactive wastes; Silicates; Waste glass; Waste management
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2016.12.023

[Display omitted] •Alkali fusion processed waste glass greatly affected on MK-based geopolymers.•Different alkaline activators were almost entirely prepared from waste glass.•Size of MK and WG particles, Si-modulus and curing temperature were governor factors.•FT-IR spectra of fused WG/MK-based matrices were deconvoluted and interpreted.•Quality gauges were approved microstructurally with limited disadvantages. 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 35.36MPa. Mechanical properties were improved via four consequential stages by lowering MK particle size to less than 38μm, loading of 3% undissolved waste glass, loading of 7% fused waste glass at SiO2/Na2O of 1.55, and early age curing at 40°C recording 80.75, 82.36, 93.08 and 97.41MPa, 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°C.