EXPERIMENTAL STUDY ON BOND BEHAVIOUR OF EXPANSIVE CONCRETE-FILLED CIRCULAR STAINLESS STEEL TUBES
Zeyu. Cheng 1*, Yuner. Huang 1 and David. Rush 2
1 the University of Edinburgh, Edinburgh, United Kingdom
Concrete-filled stainless steel tubes have the benefits both composite action between the tube and concrete, and the durability of stainless steel. However, in normal applications the bond strength between the concrete and stainless steel is weak, reducing the effectiveness of the composite action particularly when axial forces are only applied to the steel tube. This paper presents a series of push-out experiments of self-compensating expansive concrete-filled circular stainless steel tube (ECFSST). These experiments aim to investigate the increased bond strength between the infilled concrete and outer stainless steel tube due to concrete expansion, and to identify the bond behaviour mechanism. This study also examined the impact of concrete material and geometrical properties on the bond behaviour, including dosage of expansive additives, concrete strength, diameter-to-thickness ratio of outer steel tube, and height-to-outer diameter ratio of test specimens. It was found that the bond strength can reach 0.55 MPa and decrease to an average value of 0.2 MPa. Chemical adhesion and microlocking lose full function after the first push-out cycle, and macrolocking mechanism is about 28% of bond strength.
Concrete-filled stainless steel tubes; Circular hollow section; Expansive additives; Push-out test; Bond strength.