Experimental study on seismic behavior of gangue concrete frame middle joints with different gangue aggregate replacement rates

The low-cycled repeated loading experiment was carried out for gangue aggregate concrete middle joints with coal gangue aggregate replacement rates 0, 30%, 50%, 70%, 100%. The experiment was designed to investigate the joint failure modes, hysteretic characteristics, joint deformation and energy dissipation behavior of coal gangue aggregate concrete joints with different gangue aggregate replacement rates. Results show that the mechanical and failure process of coal gangue aggregate concrete frame joints, which is the same as that of normal concrete joint, may be composed of four stages: the initial cracking, the thorough cracking, the ultimate stage and the failure stage. It is found that the gangue concrete joints, with the increase of coal gangue aggregate replacement rate, are inferior to the normal concrete joint in the terms of hysteretic characteristics, joint deformation and energy dissipation behavior. (paper)