Effect of Superplasticizer and Shrinkage-Reducing Admixtures on Alkali-Activated Slag Pastes and Mortars

Superplasticizers added to Portland cement concrete yield concrete with high rheological requirements, while maintaining a low water/cement ratio (w/c) to provide good mechanical properties and durability. This article reports on a study investigating how several superplasticizers (polycarboxylates, vinyl copolymers, melamine and naphthalene-based) and shrinkage-reducing (polypropylenglycol derivatives) admixtures affect the mechanical and rheological properties and setting times of alkali-activated slag pastes and mortars. The study included two activator solutions, waterglass and NaOH, were used, along with two concentrations (4% and 5% of Na2O by mass of slag). The results showed that all admixtures, with the exception of the naphthalene-based product, lost their fluidifying properties in mortars activated with NaOH as a result of the changes in their chemical structures in high alkaline media. The authors also discuss the difference in the behavior of these admixtures when ordinary Portland cement is used as a binder.

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  • English

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  • Accession Number: 01002281
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 22 2005 1:24PM