Perforation of concrete slabs with 48 MPa (7 ksi) and 140 MPa (20 ksi) unconfined compressive strengths

We conducted perforation experiments with 25.4-mm diameter, 0.50-kg, 3.0-caliber-radius-head, ogival-nose rods and 178-mm-thick concrete slabs with 48 MPa (7 ksi) and 140 MPa (20 ksi) unconfined compressive strengths. For impact velocities between 300 and 1100 m/s, our data showed that residual velocities for the 140 MPa concrete were less than 20% lower than that for the 48 MPa concrete. Thus, for a factor of three increase in unconfined compressive strength, we measured relatively minor changes in ballistic perforation performance. We explained these results qualitatively with post-test observations and triaxial material experiments with the 48 and 140 MPa concrete materials.