Experimental Investigation of Projectile Impact Local Damage on Cementitious Composite Slabs

Abstract

This paper describes the projectile impact resistance of cement based composite slabs. The resistance is evaluated on the basis of the presented experimental program. In the experiment, local damage was inflicted by impact of defined projectiles on specimens made from normal strength concrete (NSC), steel fiber-reinforced concrete (FRC), ultra-high performance concrete (UHPC) and ultra-high performance fiber-reinforced concrete (UHPFRC) with different fiber content. Deformable ogive-nose projectiles with diameter of 7.92 mm and mass of 8.04 g with impact velocity about 700 m/s were in the experiment hitting center of the specimens. Data from the measured and visual evaluation of specimen damage were used for comparison of specimen projectile impact resistance in relation to the used material.

Influence of Different Mechanical Properties to the Concrete Penetration Resistance

“…UHPC and UHPFRC with low fiber content (0.5 and 1.0 % by volume) didn't prove any better penetration resistance. As was noted in former work [5], projectile impact on UHPC causes completely fragile failure of its samples. Absence of strain softening results in sudden material failure along path of shear and tension cracks.…”

“…Defining of sample mass loss by their weighting before and after projectile impact was also part of the experiment. Sample mass loss was very adequate indicator of projectile local damage magnitude in former work [5]. 1 Fiber ratio λ is defined as length/diameter.…”

The Influence of Different Fibres Ratio in the Cementitious Composite on Ballistic Resistance

“…The amount of microfibers is in volume percentages. The UHPFRC with 2, 3, 3.6, 4 and 4.7 % of steel fibers content in mixture volume was investigated, 2% fiber content mixture was tested in previous researches [4,5]. The amount of 4.7 % of fiber content was maximum which was able to be mixed and cast into the mould properly.…”

“…Each specimen was placed into the special mount with simulation of point supports by two screws in each corner. With regard to the safety of the shooter, some non-standardized distances of the shooter and target were also selected [3,4,5]. Projectiles were fired from the distance 6 meter for handguns and 20 meters to center of specimen for rifles.…”

Effect of Placement Method on Projectile Impact Resistance of UHPFRC

“…6). The appointed projectile has ogival nose, diameter of 7.92 mm, mass of 8.04 g and initial energy 2030 J [5,6].…”