Concrete behaviour under ballistic impacts: Effects of materials parameters to penetration resistance and modeling with PRM model

To better evaluate the vulnerability of reinforced concrete infrastructures to rigid projectile penetration, CEA-Gramat has conducted for a few years a research program with the help of French universities. The different phases appearing during the penetration process, like tunneling, scabbing or cratering, are respectively associated to several loadings like compression under high confinement, dynamic tension or shear. Each mechanism has been studied independently in laboratory at the scale of concrete material, and some parameters like curing conditions, saturation ratio, water/cement ratio, paste volume have been specially analyzed to understand their influence on the concrete behaviour. To translate the experimental results from the material scale to the structure scale, penetration tests have been performed at CEA-Gramat. Using an ogival nose projectile embedding an accelerometer system recorder, about twenty impact experiments have been carried out for velocities ranging from 230 m/s to 450 m/s. Targets were cylindrical concrete slabs with different concrete compositions. The analysis of these penetration results coupled with material characterization experiments allow identifying the material parameters playing a major role in the different mechanisms occurring during penetration. This entire experimental database can be used to validate our numerical concrete model called PRM model (Pontiroli, Rouquand, Mazars).