Recycled aggregate concrete (RAC) is a type of sustainable concrete that is produced using coarse aggregates recycled from construction and demolition wastes. Owing to its inferior mechanical properties, e.g., low strength and ductility, the application of RAC is only limited to non-structural (non-load bearing) components in buildings and bridges, where loading is little if any.
To address this shortcoming, a novel composite structural system – recycled aggregate concrete-filled stainless steel tube (RACFSST) is proposed, where the outer stainless steel tube could provide efficient lateral confinement to the inner RAC and lead to a great improvement in material strength and ductility of RAC, thus bringing the possibility of extending the application scope of RAC to general load-bearing structural components and promoting the use of sustainable RAC in construction.
This research project aims at investigating the material and buckling behaviour of RACFSST under the fire condition. A comprehensive experimental study will firstly be conducted to develop a deep understanding of the material response of confined RAC and local and global buckling behaviour of different types of RACFSST structural members in fire. The influence of various key geometric and material parameters on the fire buckling behaviour of RACFSST members will be investigated. Finally, upon verification of the residual resistances of RACFSST members in fire, design guidelines will be proposed.