The potentials of porous concrete for ballistic protection

A special porous concrete has been developed by the Delft University in collaboration with TNO. The concrete has a static compressive strength of 45 MPa. It fragments at impact into small size debris relative to reference concrete. The porous concrete was developed at laboratory scale and tested at small scale. In collaboration with the Military Science faculty of NLDA a procedure was developed to upscale the production. Panels of 0.5m x 0.5m x 0.10m were produced at slightly lower strength than realized at lab scale. These panels were used to investigate the ballistic performance of the porous concrete. The ballistic resistance proved to be comparable to that of reference concrete. The instant crushing feature of the concrete causes additional damage at the front side but the damage zone was still limited in size. Spalling at the rear side proved to be limited in comparison to the reference normal concrete. To further improve the ballistic resistance of the porous concrete, it was infiltrated with a polymer. Tests showed a considerable improvement of the penetration resistance, relative to the noninfiltrated porous concrete. The paper first summarizes the characteristics of the porous concrete developed at lab scale. The ballistic test data are presented and analyzed. The ballistic response mechanism of the porous concrete is compared with the mechanism in normal concrete. From this analysis the alternative of filling the pores emerges. Finally the paper presents the initial ballistic results for the infiltrated porous concrete.