High performance fiber reinforced concretes presents an effective solution for providing impact resistance to different impact loading. An experimental investigation of resistance of high performance fiber reinforced concrete against deformable and non-deformable projectile impact at high velocities was conducted in the framework of this master’s thesis. High performance concrete matrix with compressive strengths over 110 MPa was reinforced with discrete steel fibers in five different volumetric fractions from 0,125% to 2,0%. Impact resistance of the composite was evaluated through three main damage degrees: depth of penetration and area and volume of the impact crater.
It was confirmed, that the increment of fiber volumetric fraction does not have significant influence on the depth of penetration, but is very effective in reducing the crater area and volume, since the fibers are activated after the cracking occurs and are thus providing the residual strength to the material.
A large number of empirical and semi-analytical material models for predicting penetration depth and mass ejection were tested and evaluated through comparison to the experimental results. The best correlation to experimental results was provided by newest models, which were developed on the basics of more accurate physical assumptions.
The hypothesis, that unconfined compressive strength does not have the main influence on impact resistance, was tested as an antithesis to the basic assumption from which the majority of the material models are derived, that the depth of penetration is in inverse correlation to the square root of unconfined compressive strength. It was proven, that the depth of penetration is more influenced by concrete tensile and flexural strength, while crater volume and area are in majority controlled by unconfined compressive strength. Shear crack analysis showed, that the increment in fiber volumetric fraction provides higher impact crack resistance.
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