Recycling and reuse of construction and demolition waste in concrete-filled steel tubes: A review

- Bond behavior between recycled aggregate concrete and steel tubes was reviewed and discussed.
- Static behavior and long-term performance of RACFT members were summarized.
- Performance of recycled aggregate concrete-filled steel tube members and frames under cyclic loads were described.
- Strength prediction model of recycled aggregate concrete-filled steel tubes was proposed.

This paper presents a summary review of research performed on the mechanical behavior of concrete-filled steel tube members and frames made from recycled aggregate concrete (RAC). The paper begins with an introduction of some research progress made on the bond behavior between RAC and steel tubes. Discussion is then turned to the static behavior of recycled aggregate concrete-filled steel tube (RACFST) members, including the flexural performance of beams, concentric and eccentric load carrying capacities of stub columns and long-term performance of columns. Research findings on the performance of RACFST columns and RACFST plane frame under cyclic loads are then presented. The paper concludes with a presentation of a prediction model for the strength of RACFST by considering whether the recycled coarse aggregates have been pre-wetted or not before fabrication of the structural members. Based on these research results, it can be concluded that with proper design and construction, the application of RAC as a structural material in concrete-filled steel tube structures is feasible and safe.