A Raman spectroscopic study of the evolution of sulfates and hydroxides in cement-fly ash pastes

Nishant Garg, Kejin Wang, Steve W. Martin

Research output: Contribution to journalArticle

Abstract

Raman spectroscopy has been employed to study the evolution of sulfo-aluminate and hydroxyl phases in pastes made with ordinary Portland cement (OPC) and fly ash (FA). Three fly ashes with different CaO contents were used as a cement replacement at the level of 0 and 50% by weight. The pastes were analyzed at 0, 0.2, 2, 4, 8, 12, 16, 20, 24, 48, 72 h, and 7, 14, 21, 28, and 56 days after mixing. The wavenumber ranges used for Raman spectroscopic analysis are 950-1050 cm- 1 for evolution of sulfates and 3600-3700 cm - 1 for evolution of hydroxides. Gradual disappearances of gypsum in parallel with the formation of ettringite (AFt) are clearly observed in most paste mixes. Evolution of hydroxides showed the gradual spatial growth of portlandite. In addition to the potential benefits, the limitations of using Raman spectroscopy in study of cement-based materials are also noted in this paper.

Original languageEnglish (US)
Pages (from-to)91-103
Number of pages13
JournalCement and Concrete Research
Volume53
DOIs
StatePublished - Jul 16 2013
Externally publishedYes

Keywords

  • Ca(OH)2 (D)
  • Cement (D)
  • Fly ash (D)
  • Raman spectroscopy (nominated)
  • Sulfo-aluminate (D)

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

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