Effect of basicity on cementitious activity of modified electric arc furnace steel slag

Electric arc furnace steel slag was modified by wastes in hot-stage process with the aim to improve the cementitious activity. Effect of basicity on cementitious activity of modified steel slag was investigated in this research. The modified slag was characterized by XRD, DTA and Raman spectra techniques to investigate the correlations between structural features and the cementitious activity. The results showed that modified steel slag with a basicity index of 1.67 possessed the highest activity index, 107%, due to the precipitation of Belite, high content of amorphous phase and low polymerization degree. The polymerization degree of modified slag was demonstrated by nonbridging oxygen per tetrahedrally coordinated cations value which was calculated through curve-fitted Raman spectra. The value of modified slag increased as the basicity promoted from 1.05 to 1.67, indicating a lower degree of polymerization. Modified slag with a basicity index of 1.86 possessed the poor cementitious activity mainly because of the significant decrease of glass phase content.