Experimental investigation of the confined behavior of concrete under shear loading at high strain rates

A new experimental technique has been developed to investigate the confined shear behavior of concrete under dynamic conditions. The technique is based on the ‘Punch through shear test’ and consists in pre-stressing a concrete sample prior to testing it under shear. The pre-confinement is applied by means of a metallic cell instrumented with gages to register the stresses during the test; it consists in deforming the cell with a compressive load and then inserting the specimen into the cell. When the load is released, the cell applies a confinement to the sample. Two notches are performed from each side of the specimen and a displacement is applied to the central part in order to produce shear inside the vertical ligament. Dynamics tests are done with the Split Hopkinson Bar setup where a striker, an incident and two output bars are used. Two sets of specimens have been tested, saturated and dry concrete.