Effects of halloysite in kaolin on the formation and properties of geopolymers

Zhang, Z. and Wang, H. and Yao, X. and Zhu, Y. (2012) Effects of halloysite in kaolin on the formation and properties of geopolymers. Cement and Concrete Composites, 34 (5). pp. 709-715. ISSN 0958-9465

Abstract

A kaolin containing 31 wt.% halloysite and a relatively pure kaolin were selected to study the effects of halloysite on the dissolution behavior of precursors and the formation of geopolymers. The Al and Si concentrations in the leached solutions were studied by inductively coupled plasma-optical emission spectrometry (ICP-OES). The reaction process of metakaolin–activator mixtures was monitored by isothermal conduction calorimetry (ICC) while the reaction products were examined by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and mercury intrusion porosity (MIP). Results showed that the hal- loysite containing kaolin and its metakaolin possessed higher Si and Al dissolution rate than the purer kaolin and its metakaolin. When mixed with sodium silicate activator at 20 C, the presence of halloysite in kaolin led to a higher geopolymerization rate of metakaolin as reflected by the heat evolution rate. The presence of halloysite improved the reactivity of metakaolin but did not change the geopolymerization pathway under 20 C air curing and 80 C steam curing conditions. The products from the two metaka- olins had a similar XRD characteristic (i.e. a typically amorphous diffraction). Only a minor difference in the pore distribution and the porosity was found between those products from the two sources of metakaolins.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to published version due to publisher copyright policy (Elsevier)
Depositing User: Mr Zuhua Zhang
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Mechanical and Mechatronic Engineering
Date Deposited: 01 Oct 2012 05:11
Last Modified: 14 Oct 2013 05:26
Uncontrolled Keywords: geopolymer; halloysite; kaolin; secondary mineral; dissolution
Fields of Research (FOR2008): 09 Engineering > 0905 Civil Engineering > 090503 Construction Materials
09 Engineering > 0912 Materials Engineering > 091201 Ceramics
12 Built Environment and Design > 1204 Engineering Design > 120404 Engineering Systems Design
Socio-Economic Objective (SEO2008): B Economic Development > 87 Construction > 8798 Environmentally Sustainable Construction > 879899 Environmentally Sustainable Construction not elsewhere classified
Identification Number or DOI: doi: 10.1016/j.cemconcomp.2012.02.003
URI: http://eprints.usq.edu.au/id/eprint/21380

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