Influence of sodium chloride on the hydration of C3S blended paste. (10th March 2023)

• Record Type: Journal Article
• Authors: Sui, Shiyu; Wang, Fengjuan; Wu, Meng; Li, Shaochun; Liu, Zhiyong; Gao, Song; Jiang, Jinyang
• Is Part Of: Construction & building materials. Volume 369(2023)
• Publication Date: 2023-03-10
• Subjects: C3S -- Metakaolin -- Chloride -- AFm -- Hydration; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2023.130543
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: MK+LS showed little acceleration but high enhancement effect on C3 S hydration. Chloride could accelerate and enhance the precipitation of AFm phase. Friedel's salt formed and then changed to solid solution in system with carbonate. Abstract: Understanding the chloride influence mechanism on the hydration kinetic of cementitious materials is meaningful for the application of chloride rich raw materials. This paper explored the main hydration peak and AFm peak evolution for various chloride content in C3 S systems blended with metakaolin and limestone. Calorimetry test was applied to reveal the hydration process under chloride condition. Phase assemblage evolution was analyzed through X-Ray powder diffraction (XRD)/Rietveld analysis. It was observed that the hydration rate was accelerated and enhanced for both silicate and aluminate peaks when chloride was present. Silicate peak change comes from the ions effect of the pore solution owing to chloride. AFm peak heat release presents linear relation with chloride content. In addition, MK and LS shows little effect at the beginning and then some chemical reaction effect after the main peak. Therefore, pure Friedel's salt is formed at the beginning of hydration in all systems, while solid solution of Friedel's salt would be produced after the silicate peak in systems with limestone, which is controlled by the carbonate in the system.