Performance optimization and hydration characteristics of BOF slag-based autoclaved aerated concrete (AAC)

Basic oxygen furnace (BOF) slag, a by-product of the steelmaking process, has never been effectively utilised owing to its various drawbacks. In this study, BOF slag was used as the calcareous raw material of autoclaved aerated concrete (AAC) to successfully and completely replace lime with BOF slag. Moreover, the slurry was regulated with NaOH and a thickening agent, successfully reducing bulk density from the B07 level to the B05 level without reducing mechanical performance. The reaction products of AAC were analysed using X-ray diffraction and scanning electron microscopy. The results demonstrate that the addition of BOF slag can hinder the formation of xonotlite which offsets the other negative effects of BOF slag to a certain extent. In addition, kirschsteinite and part of C2F were involved in generating tobermorite during the autoclaving process.