Material Properties of Cement Doped with Carbonated Steel Slag Through the Slurry Carbonation Process: Effect and Quantitative Model

The preparation of concrete materials using carbonated steel slag through the slurry carbonation process is an effective method to overcome environmental problems caused by steel slag stacking and CO2 emissions. However, the relationship between material properties and CO2 sequestration efficiency has not been extensively investigated. In this study, we thoroughly investigated the property-intensifying mechanism of cement-based materials after doping with carbonated steel slag. The compressive strength, water adsorption, and soundness changes were analyzed under different conditions. Moreover, a quantitative model of the relationship between the material properties and influencing factors was analyzed by the response surface methodology (RSM). The block compressive strength and water absorption increased as the steel slag carbonation degree and curing duration increased. In addition, the soundness increased as the steel slag carbonation degree and L/S ratio increased. The compressive strength increased from 47.51 to 69.24 MPa, the water absorption increased from 0.15 to 0.27 g H2O/g solid, and the soundness decreased from +/- 4 to +/- 1 mm when the steel slag carbonation degree increased from 3 to 7 pct to 23 to 27 pct and the S/C ratio, L/S ratio, and curing duration were 0.11, 0.20 L/kg, and 28 days, respectively. The response surface methodology (RSM) results show that the theoretical maximum compressive strength was 75.85 MPa at a steel slag carbonation degree of 34.53 pct, L/S ratio of 0.15 L/kg, S/C ratio of 0.04, and curing duration of 70 days. The strategy of improving cement material properties by doping carbonate steel slag through the slurry carbonation process is demonstrated to be feasible, which broadens the collaborative horizon of CO2 sequestration and resourceful steel slag disposal.