Physical-chemical performance of coal gasification slag with calcination activation utilized as supplementary cementitious material

The utilization of coal gasification slag to prepare supplementary cementitious materials has garnered considerable interest due to environmental friendliness. In this study, a calcination activation was carried out to enhance the pozzolanic activity of coal gasification slag, and serial sintering temperatures were conducted to activate coal gasification slag in this study. The coal gasification slags were characterized by particle size analyzer, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Furthermore, the pozzolanic activity of coal gasification slag was identified through dilution test and application in blended paste. Results showed that the calcination pretreatment effectively affected the particle size distribution and mineral composition. The setting time and hydration rate were prolonged by incorporating coal gasification slag. It was crucial that the coal gasification slag calcined under 400 degrees C performed the highest reactivity and its blend presented a 4.75% higher compressive strength than neat cement at 28 d curing. AFt and AFm were mainly generated by pozzolanic reaction, and a denser microstructure that porosity decreased by 26.76 % was gained. The achievement of this study proved the feasibility of this treated coal gasification slag in building materials.