Air void morphology in fresh cement pastes

D. J. Corr, J. Lebourgeois, P. J M Monteiro*, S. J. Bastacky, E. M. Gartner

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Two different procedures are used in conjunction with low-temperature scanning electron microscopy to image the air voids in cement pastes at very early ages. The first procedure isolates the air voids from cement paste after less than 30 min of hydration, and allows them to be imaged apart from the paste. The second procedure involves quenching the fresh cement paste specimens in liquid nitrogen after 5 min of hydration. In both cases, a distinct air void shell is apparent even at these short hydration times. The shell appears to be made up of small (1-5 μm) mineral particles. The second method confirms the presence of a water-rich transition zone around the air voids in the quenched pastes, consistent with earlier studies. Foam stability studies show that sodium oleate gives more stable foams than sodium dodecyl benzene sulfonate, but is more sensitive to the presence of calcium ions.

Original languageEnglish (US)
Pages (from-to)1025-1031
Number of pages7
JournalCement and Concrete Research
Volume32
Issue number7
DOIs
StatePublished - Jul 2002

Keywords

  • Admixture
  • Cement paste
  • Freeze and thawing
  • Microstructure
  • SEM

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

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