Phase-Transition Conductometry to Study Pore Structure Evolution in Fly-Ash Mortar

Benny Suryanto, Jaehwan Kim, William John McCarter

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The durability of cement-based materials depends primarily on the environmental exposure conditions and micro-porous nature of the cementitious binder. In this paper, electrical impedance spectroscopy is exploited to study pore structure evolution in fly-ash mortars. To this end, mortar samples were exposed to a cyclic temperature regime over the temperature range 20oC ⇄ -60oC to establish the relation between pore size and the freezing/melting point of pore-water. It is shown that when the bulk resistivity and thermal response of the mortars were presented in an Arrhenius format, hysteresis was evident over a significant portion of the plots. Depression in both the freezing and thawing temperatures was evident and used to estimate the radii of capillary pore necks and cavities. It is also shown that due to on-going hydration and pozzolanic activity, and resulting pore structure refinement, the bulk resistivity above the freezing point increases with curing time, while that below the freezing point exhibits an opposite trend and attributed to the reduction in pore-neck radius which has a governing role on ice formation.
Original languageEnglish
Title of host publicationEuroCoalAsh 2019 : Proceedings
EditorsMichael J. McCarthy, Moray D. Newlands, M. Roderick Jones, Thomas D. Dyer, Laszlo J. Csetenyi, Li Zheng
Place of PublicationDundee
ISBN (Electronic)978-0-9573262-2-3
Publication statusPublished - 10 Jun 2019
EventEuroCoalAsh 2019 - Dundee and Angus Convention Bureau, Dundee, United Kingdom
Duration: 10 Jun 201912 Jun 2019

Conference

ConferenceEuroCoalAsh 2019
Country/TerritoryUnited Kingdom
CityDundee
Period10/06/1912/06/19

Keywords

  • Mortar
  • Freezing and thawing
  • Impedance
  • Arrhenius
  • Hysteresis
  • Pore radius
  • Ice formation

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