Utilization of red mud with high radiation for preparation of autoclaved aerated concrete (AAC): Performances and microstructural analysis

Millions of tons of red mud need to be disposed of in China, which caused environmental pollution. This study utilized red mud with high radiation to replace fly ash (up to 30%) to prepare autoclaved aerated concrete (AAC), and their durabilities, pore structures and microstructures were investigated correspondingly. The results indicate that the introduction of red mud led to a more viscous AAC slurry as well as the inferior post-freezing strength, which could be explained by the pores' interconnectivity and shapes. However, red mud could lead to the formation of a higher amount of tobermorite and reduce the pore size so that drying shrinkage of red mud-based AAC could be alleviated. Overall, the utilization of red mud in AAC could be an effective way to dispose of red mud in terms of intrinsic radiation reduction, facilitating its valorization and application on a large scale in practice.