Experimental study and numerical simulation on bond performance of reinforced coal gangue concrete

Abstract:

To investigate the bond-slip behavior between ribbed steel bar and coal gangue concrete, 36 cubic specimens were designed and prepared, in which coal gangue replacement ratio, concrete strength grade and rebar diameter were selected as variables, and the center pull-out tests were conducted. The results show that the bond strength of the specimen gradually decreases with the increase of coal gangue replacement ratio and the failure mode changes from pull-out failure to splitting failure. With the increase of rebar diameter, the bond strength of the specimen shows a decreasing trend, and the degree of decline of coal gangue concrete is more significant than that of ordinary concrete. As the concrete strength grade increases, the bond strength of the specimen increases significantly and the failure mode of the specimen changes from the pre-yield failure of steel bar to the post-yield failure of steel bar when the strength grade reaches C55. Based on the experimental data, a bond strength prediction model and a 3D meso-scale finite element model of reinforced coal gangue concrete members were established. The finite element model, the accuracy of which was verified, was utilized to further reveal the damage evolution and bond failure mechanism of coal gangue concrete and ribbed steel bar under pull-out force.