Compressive behaviour of steel columns filled with cold-bonded lightweight aggregate concrete

![CDATA[Lightweight concrete is of prime importance to reduce the dead weight of structures and to reduce transportation cost of aggregates and precast concrete members. Different types of lightweight aggregates (LWA) have been used in practice to make lightweight concrete, in which cold-bonded LWA is one of the alternative manufactured lightweight aggregates. This paper investigates the compressive behaviour of steel columns filled with cold-bonded LWA concrete. The cold-bonded LWA mainly contained fly ash, bottom ash and a small amount of binder (3-5%). A total of 10 stub columns were fabricated and tested accordingly. The main parameters considered in the investigation were water-to-cement ratio (0.3 and 0.5), and replacement level of limestone coarse aggregate with cold-bonded LWA (0, 25, 50, 75 and 100%). It is found that the axial stiffness and strength of the composite column decrease with increasing amount of LWA in the concrete. However, the ductility has a tendency to increase. The load-deformation curves are predicted using an existing finite element model and mechanical properties are also predicted using equations developed for normal composite columns. The prediction accuracy is reasonable. This research proves the feasibility of using cold-bonded LWA concrete to fabricate composite columns.]]