Alkali-activation potential of biomass-coal co-fired fly ash. (October 2016)

• Record Type: Journal Article
• Authors: Shearer, Christopher R.; Provis, John L.; Bernal, Susan A.; Kurtis, Kimberly E.
• Is Part Of: Cement & concrete composites. Volume 73(2016)
• Page Start: 62
• Page End: 74
• Publication Date: 2016-10
• Subjects: Fly ash -- Biomass -- Geopolymer -- Strength -- Characterization -- Microscopy; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2016.06.014
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: Co-fired fly ash, derived from the co-combustion of coal and biomass, is examined as a potential precursor for geopolymers. Compared to a coal fly ash, two co-fired fly ashes have a lower vitreous content and higher carbon content, primarily due to differing combustion processing variables. As a result, binders produced with these co-fired fly ashes have reduced reaction potential. Nevertheless, compressive strengths are generally highest for all ashes activated with solutions with a molar ratio of SiO2 /(Na2 O + K2 O) = 1, and these mixes reach the highest extent of reaction among those studied. Activation with sodium hydroxide solution forms zeolitic phases for all ashes. The thermal and dilatometric behavior of the coal and co-fired fly ash geopolymers is similar between equivalent mix designs. These results indicate that co-fired fly ashes can be viably used to form alkali-activated geopolymers, which is a new beneficial end-use for these emerging waste materials.