Experimental and numerical study of the cyclic behavior of exterior RC beam-column joints made with recycled concrete

An experimental and numerical investigation about exterior reinforced beam-column joints made with recycled concrete, and subject to horizontal reversed cyclic loading, is shown in this paper. Three real scale RC joints were casted with electric arc furnace slag as recycled coarse aggregate, and then tested under quasi-static cyclic loading, to study the influence of this kind of “green concrete” on the global behavior of the specimens. Particularly, ultimate load, hysteresis response and dissipated energy were analyzed. The joints exhibited the same failure mode, which involved the shear failure of panel joint and yielding of beam steel longitudinal bars: this kind of failure is indeed the most influenced by concrete properties. Then a numerical investigation was carried out, consisting of three- dimensional nonlinear finite element (FE) models, which were validated with the experimental results. Lastly, a parametric study was carried out to understand the effects of column axial load, beam longitudinal reinforcement bar amount and column transverse reinforcement ratio. Results indicate that, in all the analyzed cases, the seismic performance of the joints made with EAF slag concrete at least comparable than with conventional material.