Abstract
This study evaluates the reaction kinetics, phase assemblage, and microstructure evolution of Na2SO4-activated slag cements produced with three commercial slags. The main reaction products identified are ettringite and calcium aluminosilicate hydrates, alongside a poorly crystalline SO42- intercalated Mg-Al-layered double hydroxide (LDH) phase. Results revealed that the Al2O3 slag content alone does not correlate with the cement performance. While pastes made with a higher Al2O3 content slag exhibit faster reaction kinetics, those made with a slag with a higher Mg/Al ratio developed superior compressive strength and reduced porosity over extended curing periods. Thermodynamic modelling simulations indicate that sulfate consumption occurs via ettringite and LDH phase formation, influencing the slag reaction degree, pH value, and porosity reduction in these cements. This research highlights the critical role of slag composition in controlling microstructure and, consequently, performance of sodium sulfate activated slag cement pastes.
| Original language | English |
|---|---|
| Article number | 100117 |
| Journal | CEMENT |
| Early online date | 20 Sept 2024 |
| DOIs | |
| Publication status | Published - 1 Dec 2024 |
Data Availability Statement
The data associated with this paper are openly available from the University of Leeds Data Repository, at https://doi.org/10.5518/1542.Acknowledgements
Stuart King and Duncan Hedges are greatly acknowledged for their training in SEM sample preparation.Funding
This research is sponsored by the Engineering and Physics Science Research Council (EPSRC) via an early career fellowship EP/R001642/1. Z. Yue is grateful to the University of Leeds for his PhD studentship. The SEM analysis was conducted at the UKCRIC National Centre for Infrastructure Materials at the University of Leeds grant EP/P017169/1.