Mechanochemical Properties and Microstructural Framework of Fly Ash Based Geopolymer Concrete Containing Slag Additives

International Journal of Chemistry | Vol. 4, No. 6, June 2013 | pp. 41–48

DOI: 10.46882/2013/IJC/000057

Article Type: Original Research Paper

Title: Mechanochemical Properties and Microstructural Framework of Fly Ash Based Geopolymer Concrete Containing Slag Additives

Names of Authors: T. S. Ani¹, M. F. Montemor²*

Authors’ Affiliations:
¹Department of Electronic and Chemical Engineering, Enugu State University of Science and Technology, Enugu, Nigeria.
²Department of Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal.

Abstract: The replacement of conventional cement with fly ash-based geopolymer binders helps lower industrial greenhouse gas footprints, though curing parameters require mechanical optimization via supplementary calcium sources. This research tracks the structural development and mechanical profiles of binary geopolymer cements synthesized from class F fly ash integrated with ground granulated blast furnace slag (GGBS) at replacement levels from 0% to 40%. Alkaline activation was executed utilizing structural mixtures of sodium silicate and 12 M sodium hydroxide solutions. Hardening kinetics and microstructural phases were analyzed using X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, and Scanning Electron Microscopy (SEM). FT-IR spectra demonstrated the formation of a rigid aluminosilicate network, indicated by the prominent framework stretching bands at 995 cm⁻¹. Compressive strength experiments showed that concrete cubes prepared with 30% GGBS substitution reached a maximum compressive value of 52.4 MPa after 28 days of curing at room temperature, outperforming pure fly ash controls. SEM characterization revealed a highly dense matrix featuring co-existing sodium aluminosilicate gel (N-A-S-H) and calcium silicate hydrate (C-S-H) gel structures, which significantly reduces structural porosity.

Keywords: Geopolymer; Fly ash; Ground granulated blast furnace slag; Compressive strength; Microstructure; C-S-H gel

Manuscript Timeline: Received: September 10, 2012; Revised: October 22, 2012; Accepted: November 15, 2012; Published: June 08, 2013.

Citation: Ani, T. S., & Montemor, M. F. (2013). Mechanochemical Properties and Microstructural Framework of Fly Ash Based Geopolymer Concrete Containing Slag Additives. International Journal of Chemistry, 4(6), 41–48.

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