Effect of free water content on the penetration of concrete

Abstract

A numerical study is presented herein on the effect of free water content on the penetration of concrete targets subjected to projectile impact. The paper consists of two parts: the first part proposes a material law that considers the influence of free water content by modifying a recently developed computational constitutive model for concrete; the second part performs the numerical simulations of the penetration of plain concrete targets struck by an ogival-nosed projectile using the material law. The present material law takes into account pressure dependency, strain rate sensitivity, shear damage and tensile softening, loading path dependency (Lode angle) and free water content. Various equations are obtained and the values of relevant parameters are estimated. It is demonstrated that the modified constitutive model correlates well with available test data for concrete. It is also demonstrated that the present model predictions are in good agreement with the experimental observations for wet plain concrete targets struck transversely by an ogival-nosed projectile in terms of sizes of both impact and scabbing craters, time-histories of load, penetration and velocity and that the impact resistance increases with increasing free water content which results in smaller penetration depth in wet concrete target than that in dry one in the case of penetration and smaller residual velocity for wet concrete slab than that for dry one in the case of perforation.