Dynamic mechanical properties of concrete materials subjected to passive confining pressure produced by a steel sleeve

The 75-mm-diameter split Hopkinson pressure bar (SHPB) technique was applied to experimentally obtain axial or radial stress and strain peaks,average strain rates of different concrete specimens laterally confined by steel sleeves under different impact loads.The damage values of concrete materials were calculated,the damage situations of concrete materials under impact load were described,and the experimental results were analyzed.It is indicated that ductibility and damage resistance of concrete materials increase under passive confining pressure.The failure strains of concrete materials under passive confining pressure is 1.8～2.8 times as large as that in the conventional SHPB experiments.Failure stress is above 150 MPa,which is 2～5 times as large as the static failure stress without passive confining pressure.The result is helpful for the investigation on security protection and failure law of concrete under the lateral confining conditions.