Influence of fly ash on the pore structure and shrinkage characteristics of metakaolin-based geopolymer pastes and mortars

Yang, Tao and Zhu, Huajun and Zhang, Zuhua (2017) Influence of fly ash on the pore structure and shrinkage characteristics of metakaolin-based geopolymer pastes and mortars. Construction and Building Materials, 153. pp. 284-293. ISSN 0950-0618


Abstract

This study investigates the pore structure and shrinkage behavior of metakaolin-based geopolymer pastes and mortars containing 0–30% fly ash. Fly ash substitution decreases average reactivity of the solid precursors, resulting in a lower reaction rate and accompanying longer reaction time. Composition of the sodium aluminosilicate (N-A-S-H) gel formed in the geopolymers has been changed, and the continued reaction after hardening of the pastes generates a more compact binding gel phase with lower Al/Si ratio. Refinement of the pore structure entails a higher capillary tension developed in the binders to increase the autogenous shrinkage, but also restricts the water evaporation from the pore networks, resulting in a decreased drying shrinkage. The geopolymer mortars provide higher compressive strength and lower total shrinkage when compared with the pastes.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -)
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -)
Date Deposited: 31 Jan 2020 06:07
Last Modified: 13 Feb 2020 22:52
Uncontrolled Keywords: Geopolymer cement; Metakaolin; Fly ash; Shrinkage; Pore structure
Fields of Research : 09 Engineering > 0905 Civil Engineering > 090503 Construction Materials
Socio-Economic Objective: B Economic Development > 87 Construction > 8703 Construction Materials Performance and Processes > 870301 Cement and Concrete Materials
Identification Number or DOI: 10.1016/j.conbuildmat.2017.05.067
URI: http://eprints.usq.edu.au/id/eprint/37705

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