Rheology and setting of alkali-activated slag pastes and mortars: Effect of organic admixture

Marta Palacios, P. F G Banfill, Francisca Puertas

Research output: Contribution to journalArticle

70 Citations (Scopus)

Abstract

The rheology of waterglass-(Na2O·nSiO2· mH2O) and NaOH-activated slag pastes and mortars depends on the nature of the alkaline activator used: in waterglass-activated slag pastes and mortars, the extensive structural breakdown under shear makes the Herschel-Bulkley model a better fit to the down ramp of the flow curve, whereas NaOH-activated pastes and mortars, such as portland-cement pastes and mortars, behaved like Bingham fluids. Admixtures were unable to reduce the yield stress of waterglass-activated slag pastes, but the inclusion of a naphthalene derivative admixture in NaOH-activated slag pastes reduced the yield stress by 80%. The problem of undesirably short setting times for waterglass-activated slag mortars and concretes could be overcome by an extended mixing time, giving an initial set of nearly 3 hours. Copyright © 2008, American Concrete institute. All rights reserved.

Original languageEnglish
Pages (from-to)140-148
Number of pages9
JournalACI Materials Journal
Volume105
Issue number2
Publication statusPublished - Mar 2008

Keywords

  • Alkali-activated cement
  • Cement paste
  • Mortar
  • Rheology
  • Setting
  • Shrinkage

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    Palacios, M., Banfill, P. F. G., & Puertas, F. (2008). Rheology and setting of alkali-activated slag pastes and mortars: Effect of organic admixture. ACI Materials Journal, 105(2), 140-148.