Toward an indexing approach to evaluate fly ashes for geopolymer manufacture. (July 2016)

• Record Type: Journal Article
• Authors: Zhang, Zuhua; Provis, John L.; Zou, Jin; Reid, Andrew; Wang, Hao
• Is Part Of: Cement and concrete research. Volume 85(2016)
• Page Start: 163
• Page End: 173
• Publication Date: 2016-07
• Subjects: Alkali activated cement -- Fly ash -- X-ray diffraction -- Compressive strength; Cement -- Periodicals; Cement -- Research -- Periodicals; Concrete -- Periodicals; Concrete -- Research -- Periodicals; Ciment -- Périodiques; Béton -- Périodiques; Cement; Concrete; Periodicals; 620.135
• DOI: 10.1016/j.cemconres.2016.04.007
• Languages: English
• ISSNs: 0008-8846

Abstract

Abstract: Variations between fly ashes can lead to significant differences in the geopolymers derived from them, in both microstructural and mechanical properties. This study assesses the effect of physical, crystallographic and chemical characteristics of fly ash on geopolymerisation performance and the strength of the resulting binders. Physical and glass chemistry factors are combined to develop a comprehensive index to evaluate the suitability of fly ashes for the production of high-strength geopolymers. An equation for this index is proposed, developed using five typical low-calcium fly ashes and then validated against a further eight literature datasets, showing a good relationship between the ranking order of the calculated index and the compressive strengths of geopolymer pastes produced with comparable activator and paste workability. This index can be used to screen the source materials, which is of significant value in moving alkali activated cements towards acceptance in practice. Highlights: Reactivity index (RI) is proposed to assess fly ash for geopolymer manufacturing. RI combines ash particle of physical, crystallographic and chemical characteristics. The development of RI is a big step towards standardisation of geopolymer. RI will be powerful in predicting the strength range of geopolymer in industry.