2025/05/12 by Ning Li, Cise Unluer · 1 voice
Engineering · Environmental Science · #CO2 Sequestration and Geologic Interactions #Concrete and Cement Materials Research #Innovations in Concrete and Construction Materials
paper · doi:10.1016/j.cemconcomp.2025.106121
openalex publication_date 2025/05/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
With the growing interest in utilizing metallurgical slag for mineral carbonation, there is an urgent need to explore the application of flue gas-carbonated slag. This study investigated the microstructure of steel slag powder (SSP) carbonated under 10% CO 2 concentration and its impact on the hydration, rheological behavior and compressive strength of cement pastes. The primary carbonation products of SSP were nano-CaCO 3 and amorphous aluminosilicate gel, with aragonite and calcite forming as the main calcium carbonate crystals. Nano-CaCO 3 and amorphous gel actively participated in cement hydration, forming monocarboaluminate and C-S-H gel, respectively. These reactions enhanced the degree of hydration and strengthened the interface between SSP and the hydrated cement matrix. In addition, the incorporation of moderately carbonated SSP (3 h) improved flow stability and reduced thixotropy due to better particle dispersion, while extended carbonation increased viscosity and structural recovery. The compressive strength of cement pastes containing 20 wt.% SSP carbonated for 3 hours was 21.6% higher than those with uncarbonated SSP, along with a 4.5% CO 2 uptake in SSP. However, a higher degree of carbonation reduced the reactivity of SSP as a supplementary cementitious material (SCM). This study provides scientific insights and a practical method for preparing a high-quality SCM by utilizing flue gas and SSP as a cement substitute.