Experimental and numerical investigations of interfacial bond in self-compacting concrete-filled steel tubes made with waste steel slag aggregates

Abstract

New self-compacting concrete (SCC) mixtures were designed to improve the interfacial bond strength in concrete-filled steel tubes (CFST) at 30 days and one year. The proposed SCC mixtures involved the strengthening of bond strength by using waste steel slag aggregates (SSA). A total of thirty-six circular and squared tube specimens with different ratios (0%, 25% and 50%) of SSA as a replacement by weight of coarse and fine aggregates in SCC were initially prepared. The results revealed that the using of SSA in SCC enhanced the specimens' bond strength for both shapes of steel tubes and the bond strength was reduced with an increase of concrete's age. Additionally, the incorporating of SSA did not decrease the loss in bond strength at one year. A three-dimensional non-linear finite element (FE) analysis was further conducted to simulate the interfacial bond-slip mechanism between two surfaces of the infill concrete and inner steel tubes.

Keywords

• Concrete-filled steel tube (CFST)
• Self-compacting concrete
• Push-out test
• Load-slip behaviour
• Steel slag
• Finite element model