The effects of phase changes on the bonding property of geopolymer to hydrated cement

Zhu, Huajun and Zhang, Zuhua and Deng, Fenggan and Cao, Yalong (2013) The effects of phase changes on the bonding property of geopolymer to hydrated cement. Construction and Building Materials, 48. pp. 124-130. ISSN 0950-0618

Abstract

Using geopolymers as bonding materials could be an alternative solution to the concrete repair. This study reports the effects of phase changes on the bonding property of geopolymer to hydrated cement. A geopolymer binder was prepared by activation of heated kaolin with sodium silicate solution, bonded with 28 days aged cement paste and cured under different conditions. The experimental results demonstrated that under the 20C air curing conditions, the bond strength achieved 1.3 MPa at 7 days and increased to 1.5 MPa at 28 days. While under the 80C steam and water curing conditions, the bond strength decreased by 31% and 37% respectively. The XRD, FTIR and SEM analysis of the geopolymers and hydrated cement pastes show that the strength loss is due to two factors: (1) the increased porosity in cement paste due to the water loss and/or crystallization of C-S-Hs; and (2) the mineralogical change (crystallization) in geopolymer binder which becomes more ordered structures. The increased porosity and the crystallization either in cement or geopolymer generate local stress and weak regions at the interface. This study suggests that the stability of metakaolin-based geopolymers should be taken into consideration when they are used as bonding or coating materials for concrete repair, particularly at the conditions with elevated temperatures.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2013 Elsevier Ltd. All rights reserved. Published version deposited in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Date Deposited: 15 Aug 2013 00:12
Last Modified: 30 Jul 2014 23:08
Uncontrolled Keywords: bond strength; bonding materials; concrete repair; crystallization; geopolymer; interface
Fields of Research : 09 Engineering > 0905 Civil Engineering > 090501 Civil Geotechnical Engineering
09 Engineering > 0905 Civil Engineering > 090505 Infrastructure Engineering and Asset Management
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.2013.06.095
URI: http://eprints.usq.edu.au/id/eprint/23898

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