Abstract: In order to find a new method of utilizing steel slag, the steel slag aggregate from Jinan Iron and Steel Plant was placed in an airtight container and carbonated with 100 % CO₂. Experimental results showed that steel slag could absorb CO₂ under a certain pressure, and the strength of steel slag specimen after carbonation was greatly improved compared with that without carbonation. When the water-cement ratio of steel slag powder was 14.5 % by gravimetric method, the weight gain rate of carbonation of steel slag brick was 15.05 %, and the corresponding compressive strength and flexure strength were 36.88 MPa and 9.69 MPa respectively. According to XRD and FE-SEM microscopic test methods, the reason for the improvement of mechanical properties of specimens was that the Ca²⁺ in steel slag, the water added with CO₂ carbonated to generate CaCO₃, resulting in a denser microstructure and reducing pore diameter.

Key words: steel slag, carbonation, CO₂ absorption, mechanical properties, steel slag products