Microstructure and phase evolution of alkali-activated steel slag during early age

This work aims to investigate the early age evolution of alkali-activated steel slag under curing condition of 60 °C. Microstructural characterization and reaction degree of alkali-activated steel slag (Isothermal calorimetric, scanning electron microscope, Transmission electron microscopy, Fourier Transform Infrared Spectrometer, and 29Si nuclear magnetic resonance) were carried out. The results showed that the densifying microstructure of aluminosilicate gel significantly increases, attributing to the increasing of reaction degree due to the formation of Si-O-T, in the early evolution of alkali-activated steel slag at 60 °C curing condition. The 29Si structure of Q0 in steel slag gradually converted into Q1 and Q2 in the intermediate products which represented the formation of aluminosilicate gels. The evidence indicated that the steel slag can be an alternative raw material in alkali activated application.