Experimental study on autoclaved aerated concrete from coal gangue and iron ore tailings.

For comprehensive utilization of coal gangue and iron ore tailings, XRD, FE-SEM and EDX were used to analyze hydration products and microstructure of autoclaved aerated concrete (AAC) mainly from coal gangue and iron ore tailings. Furthermore, it was studied that the influence of raw materials and the optimal thermal activation temperature of coal gangue to physical and mechanical prosperities. The results show that 600 °C is the optimal calcination temperature AAC with bulk density of 608 kg/m³ and strength of 3.64 MPa, which can reach the requirements of A3.5, B06 level of AAC product regulated by "autoclaved aerated concrete block" GB 11968-2006. There exists ettringite before autoclaved and the main hydration products are tobermorite, C-S-H gel and hibschite, which is globular and botryoidalis. [ABSTRACT FROM AUTHOR]