Research Of Mechanical Behavior On Eccentric Compressive Short Columns And Axial Compressive Long Columns With Recycled Aggregate Concrete Filled Circular Steel Tube

Since the reform and opening up, the infrastructure and urbanization of China develop fast, but it also generate a lot of waste concrete which is the main component of the construction waste, it not only occupies the land but also pollutes the environment. Waste concrete can be made up into recycled aggregate concrete (RAC) after treatment then used in construction, which is accepted as one of the important measures to realize the sustainable of building resources currently. However, considering the mechanical properties of RAC declines relative to natural concrete (NC) and the increase of variability, now the RAC is used mostly in non-structural system such as roads. In order to make better use of the RAC, some scholars generate a idea of filling the RAC into the steel tube to make up the recycled aggregate concrete filled steel tube (RACFST), which not only improves the mechanical properties of the RAC, but also plays their respective advantages both steel tube and the RAC, this provides a new way for the utilization of waste concrete.So far, domestic and foreign scholars has carried out some research for the recycled aggregate concrete filled circular steel tube (RACFCST) columns, this paper will link some research which has been carried out nowadays, focusing to analyse the impact of confinement index and eccentricity for short columns and also the impact of confinement index and slenderness ratio for long columns on mechanical properties. In this paper, eight short columns of RACFCST and six long columns of RACFCST were test by using eccentricity, confinement index and slenderness ratio as the basic parameters, the main work includes:the failure process and mode of specimens were analysed; the curves of load-deformation and load-strain were study; the factors which affecting the ultimate bearing capacity of specimens were analysed, the applicability of domestic and foreign specification of concrete filled steel tube for calculating the capacity of recycled aggregate concrete filled circular steel tube eccentric compressive short column and axial compressive long column were study; finally, the simulation of the finite element were analysed, providing reference for the application of the recycled aggregate concrete filled circular steel tube structures.