Time-dependent behaviour of recycled concrete filled steel tubes using RCA from different parent waste material

This paper intends to investigate how the creep behaviour of recycled aggregate concrete filled steel tubes (RACFST) is affected by the strength of the parent waste concrete that used to produce the recycled coarse aggregates (RCAs). Long-term tests were performed on ten RACFST members. A creep model was suggested to account for the influence of the strength of the parent waste concrete. Based on an extensive parametric study, it was found that with the strength of the parent waste concrete varying between 35 MPa and 70 MPa, a maximum of 37% difference can be achieved in the long-term deformations of the RACFST members.