Repeated Projectile Impact Tests on Multi-Layered Fibrous Cementitious Composites

This research aims to experimentally evaluate the behaviour of multi-layered fibrous cementitious composites with intermediate Glass Fibre Meshes (GFM) under repeated projectile load. The impact load was subjected through a convex edge projectile needle at a low velocity on cylindrical specimens of three-layered fibrous cementitious composites, which have two different steel fibre distributions. In series A mixtures, a constant steel fibre dosage of 2.5% by volume was used. On the other hand, the fibre dosage of the outer layers was 3.0%; while it was 1.5% in the middle layer of series B mixtures. The number of intermediate GFM was the variable that distinguishes the mixtures of each series. The resistance to projectile impacts was evaluated on the basis of penetration depth, near surface distortion, weight loss, damage ratio and failure pattern. The test results showed that due to the combined effect of steel fibre and GFM, significantly lower weight losses were recorded for series A and B specimens compared with reference specimens. However, the different fibre distributions (series B) led to lower penetration depths and weight losses with less surface distortion compared with the fixed fibre distribution (series A). The reduction in the destroyed front surface area of series A specimens compared with reference specimens ranged from 27.8 to 38.1%; while that of series B specimens ranged from 34.8 to 53.4%. In addition, a simplified analytical model was introduced to predict the ejected composite mass. The model predictions were found to be in good agreement with the experimental masses.