Influence of lignosulfonate on the early age rheology and hydration characteristics of cement pastes

Abstract

Four different cements made from gypsum mixed with clinkers possessing varying amounts of clinker phases were employed to investigate the influence of lignosulfonate on the early age rheological and hydration properties of cement pastes. Two test methods were employed; the parallel plate rheometry and isothermal calorimetry. Here, lignosulfonate was quantitatively shown to impact the early age hydration of cement pastes depending on the C₃A and C₃S compositions, in the respective order. A threshold amount of ~4.6% C₃A is needed to sufficiently impair the performance of lignosulfonate at normal working dosages (0.4% bwoc). When high amounts of C₃A was present (~10%), flash set of the cement paste occurred even at the low dosage of 0.2% bwoc of lignosulfonate. When cement possessed low amount of C₃A, lignosulfonate mainly retarded the hydration of C₃S, but this effect decreased when the C₃S was doped with Al.

Keywords:

• lignosulfonate
• cement
• C₃A
• retardation
• hydration
• rheology

Acknowledgments

This work is funded as part of the Project ‘Lignosulfonate for use in concrete with reduced clinker factor and in geopolymer concrete’ sponsored by the Research Council of Norway.