Deep insight into mechanical behavior and microstructure mechanism of quicklime-activated ground granulated blast-furnace slag pastes

Guang Hua Cai, Yi Fan Zhou, Jiang Shan Li, Li Jun Han, Chi Sun Poon

Research output: Journal article publicationJournal articleAcademic researchpeer-review

24 Citations (Scopus)

Abstract

Ground granulated blast-furnace slag (GGBS) could be used as a potential low-carbon binder when activated by a moderate activator. The use of seawater in producing construction materials has increasingly attracted attention in some coastal engineering with scarce freshwater. This study aims at studying the impact of quicklime proportions on the mechanical behavior and microstructure of the binder. The mechanical behaviors were investigated through unconfined compression tests. The hydration kinetics and microstructure characteristics were examined using XRD, TGA, FTIR, and SEM-EDX. The results indicated that the hydration heat and exothermic peaks enhanced with the quicklime proportion. The exothermic peaks were observed in the first few minutes and 4–18 h. The quicklime-GGBS pastes generated the highest UCS (>18 MPa) occurred at a quicklime proportion of 0.15. The platy-like portlandite, fibrous calcium silicate hydrate (CSH), needle-like ettringite (AFt), and Friedel's salt (Fs) were detected in XRD and SEM. The Cl in seawater promoted the formation of Fs. The XRD peaks of CSH and AFt/Fs raised and then descended with the quicklime proportion, and reached the maximum at the quicklime content of 0.15. The mass percentage of CSH and AFt/Fs from TGA first increased and then became stable when the quicklime content was 0.1–0.15. The number of amorphous GGBS particles and pores decreased under the quicklime proportion of 0.05–0.15, while the portlandite increased as the quicklime content changed from 0.15 to 0.3. Overall, the quicklime-GGBS binder could provide a potential sustainable construction material in waste recycling and freshwater saving.

Original languageEnglish
Article number104767
JournalCement and Concrete Composites
Volume134
DOIs
Publication statusPublished - Nov 2022

Keywords

  • Ground granulated blast-furnace slag
  • Mechanical behavior
  • Microstructure
  • Mix design
  • Slag activator

ASJC Scopus subject areas

  • Building and Construction
  • General Materials Science

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