Accurate determination of the 'time-zero' of autogenous shrinkage in alkali-activated fly ash/slag system

Ma, Y. and Yang, X. and Hu, J. and Zhang, Z. and Wang, H. (2019) Accurate determination of the 'time-zero' of autogenous shrinkage in alkali-activated fly ash/slag system. Composite Part B: Engineering, 177 (Article 107367). ISSN 1359-8368


Abstract

Autogenous shrinkage based on different 'time-zero' may result in underestimation/overestimation on the
cracking potential of alkali-activated fly ash/slag (AAFS). This study reports an experimental investigation on the
'time-zero' of AAFS pastes characterized by different techniques. It is found that the internal capillary pressure
in AAFS pastes significantly increased after 5–7.5 h, which is far beyond the final setting time that is normally
regarded as 'time-zero' for Portland cement. The transition time derived from capillary pressure method directly
captures the alteration of capillary stress in AAFS, which matches well with the change of the shrinkage slope.
Due to the moisture equilibrium between the specimens and humidity sensor, it is hard to use the measured
internal relative humidity to determine the real “time-zero” of AAFS. This research finds that the onset of
capillary pressure in AAFS paste provides a more scientific and accurate determination of “time-zero”.


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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, in accordance with the copyright policy of the publisher.
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: 19 Feb 2020 06:44
Last Modified: 24 Feb 2020 01:34
Uncontrolled Keywords: autogenous shrinkage, time-zero, capillary pressure, internal RH, alkali-activated fly ash/slag
Fields of Research : 09 Engineering > 0905 Civil Engineering > 090503 Construction Materials
Funding Details:
Identification Number or DOI: 10.1016/j.compositesb.2019.107367
URI: http://eprints.usq.edu.au/id/eprint/37888

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