Early hydration of C3A–gypsum pastes with Ca- and Na-lignosulfonate. (January 2016)

• Record Type: Journal Article
• Authors: Danner, Tobias; Justnes, Harald; Geiker, Mette; Lauten, Rolf Andreas
• Is Part Of: Cement and concrete research. Volume 79(2016)
• Page Start: 333
• Page End: 343
• Publication Date: 2016-01
• Subjects: Admixture (D) -- Ca3Al2O6 (D) -- Ettringite (D) -- Hydration (A) -- X-ray diffraction (B); Cement -- Periodicals; Cement -- Research -- Periodicals; Concrete -- Periodicals; Concrete -- Research -- Periodicals; Ciment -- Périodiques; Béton -- Périodiques; Cement; Concrete; Periodicals; 620.135
• DOI: 10.1016/j.cemconres.2015.10.008
• Languages: English
• ISSNs: 0008-8846

Abstract

Abstract: The early age phase development during the hydration of C3 A–gypsum pastes with 1 and 4% Ca- or Na-lignosulfonate (CLS and NLS) was investigated using isothermal calorimetry, in-situ XRD, thermogravimetry, mass spectroscopy, and SEM analysis. With 1% CLS or NLS neither retardation of C3 A dissolution nor retardation of ettringite formation was observed. When LS was added in a concentration of 4%, C3 A and gypsum dissolution were slightly retarded. Gypsum depletion was delayed in all pastes containing CLS or NLS. 1% CLS or NLS increased the amount of AFm-phases formed within 24 h, while the amount of AFm was reduced with 4% CLS or NLS. The initial heat flow increased and the heat flow in the gypsum depletion peak was reduced with 1 and 4% CLS. With 4% NLS no initial heat flow was measured and the heat developed slowly within the first 15 min of hydration in the C3 A–gypsum paste.