Effects of activator characteristics on the reaction product formation in slag binders activated using alkali silicate powder and NaOH

Deepak Ravikumar, Narayanan Neithalath

Research output: Contribution to journalArticle

82 Scopus citations

Abstract

The influence of different levels of alkalinity, expressed using the Na 2O-to-source material ratio (n) and activator SiO 2-to-Na 2O ratio (M s), on the compressive strength development of, and reaction product formation in sodium silicate and NaOH powder activated slag binder systems is discussed. Higher n value mixtures are found to exhibit higher early and later age compressive strengths. An increase in M s results in reduced early age and slightly increased later age strengths. Compositional coefficients, which are functions of n and M s are proposed, that relate to the early and later age strengths of the activated slag binders as well as to the shift in the FTIR spectra. The reaction product formation in these systems as a function of the total alkalinity is explained using the shifts of the dominant peak in the FTIR spectra. Fundamental changes in reaction products of powder activated binders as a function of alkalinity is observed. The deductions from the peak shifts are substantiated using the FTIR spectra of the pastes before and after salicylic acid-methanol (SAM) attack.

Original languageEnglish (US)
Pages (from-to)809-818
Number of pages10
JournalCement and Concrete Composites
Volume34
Issue number7
DOIs
StatePublished - Aug 1 2012

Keywords

  • Alkali-activated slag
  • C-S-H
  • Compressive strength
  • FTIR
  • Salicylic acid-methanol attack
  • Silica-rich gel
  • Silicate polymerization

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

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