Understanding the roles of activators towards setting and hardening control of alkali-activated slag cement

Li, Ning and Shi, Caijun and Zhang, Zuhua (2019) Understanding the roles of activators towards setting and hardening control of alkali-activated slag cement. Composites Part B: Engineering, 171. pp. 34-45. ISSN 1359-8368


Abstract

Sodium silicate-activated slag often gives high early strength but sets too rapidly. Commercial retarders for Portland cement and partial replacement with other cementitious components in alkali-activated slag (AAS) system have been proven ineffective. This study investigated the approach of controlling setting by altering activator ion composition and silica polymer status. The roles of activators during the alkali-activation process were studied via pore solution chemistry analysis and microstructural analysis of hydration products. The addition of Na2CO3 does not, but NaOH does alter the polymerization of silicate ion groups in sodium silicate solution due to the increases in pH and Na2O concentration. The specific effects of Na2CO3 on the setting and hardening of AAS depend on the relative contents of NaOH and Na2O·2SiO2 in alkaline solution. The reaction degree of AAS is dependent on activator compositions, which govern the kinetics of formation and intrinsic characteristics of the reaction products calcium aluminosilicate hydrates. The setting and strength development of sodium silicate-activated slag can be controlled by manipulating the compositions of Na2CO3-NaOH-Na2O·2SiO2.


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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: 23 Jan 2020 23:59
Last Modified: 30 Jan 2020 02:48
Uncontrolled Keywords: Alkali-activated cements, Setting, Compressive strength , Hydration, Na2CO3
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.compositesb.2019.04.024
URI: http://eprints.usq.edu.au/id/eprint/37689

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