Electrical conductivity based characterization of plain and coarse glass powder modified cement pastes

Nathan Schwarz, Matthew DuBois, Narayanan Neithalath

Research output: Contribution to journalArticle

56 Citations (Scopus)

Abstract

This paper describes the use of electrical conductivity to characterize plain and coarse glass powder modified cement pastes. It is observed that the glass powder addition facilitates improved hydration of the cement grains. For the proportions investigated in this study, and the particle size of glass powder, this advantage is negated by the reduced amount of hydration products, i.e., the dilution effect. The variation of electrical conductivity and its derivative with time can be related to the various phases in the microstructural development of the paste. It is observed from the time derivative of conductivity plots that the addition of glass powder results only in minor changes in the setting time of the pastes. Higher the glass powder content, higher the normalized conductivity (ratio of conductivity at a certain glass powder content to that of plain paste) at very early times, and then it falls to a value closer to or less than 1.0 at later times. A parallel model is used to represent effective conductivity as a function of the pore solution conductivity, porosity, and pore connectivity factor. The pore solution conductivity increases with increase in glass powder content. The porosity of the pastes reduces with increase in glass powder content at early ages and increases at later ages. A reduced pore connectivity factor is observed for pastes with higher glass powder content at later times. However, this does not imply increased volume of hydration products as is commonly interpreted for normal pastes, but the electrical conduction pathways are made more tortuous by the relatively large volume of un-reacted filler material in the pore structure.

Original languageEnglish (US)
Pages (from-to)656-666
Number of pages11
JournalCement and Concrete Composites
Volume29
Issue number9
DOIs
StatePublished - Oct 2007
Externally publishedYes

Fingerprint

Ointments
Powders
Cements
Glass
Hydration
Porosity
Derivatives
Electric Conductivity
Pore structure
Dilution
Fillers
Particle size

Keywords

  • Cement paste
  • Characterization
  • Electrical properties
  • Glass powder
  • Hydration
  • Microstructure
  • Pore connectivity factor
  • Porosity

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering
  • Ceramics and Composites

Cite this

Electrical conductivity based characterization of plain and coarse glass powder modified cement pastes. / Schwarz, Nathan; DuBois, Matthew; Neithalath, Narayanan.

In: Cement and Concrete Composites, Vol. 29, No. 9, 10.2007, p. 656-666.

Research output: Contribution to journalArticle

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