Protective components made of steel fiber reinforced concrete under contact detonation

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As a part of a research project at the University of the German Armed Forces we investigate steel fiber concrete for use in protective structures.At the chair for concrete construction of the University of German Armed Forces a literature study on protective concrete components under gunfire and contact detonation was conducted. In a first short experimental study tests were performed in order to obtain data for numerical modeling and for supplementary test setups.In the main research project different mixtures of steel fiber concrete were produced and investigated under gunfire and contact detonation. For the concrete local raw material from the area of mission was used as aggregates and cement. Plates for the contact detonation with different thicknesses, varying fiber geometries and reinforcement systems were produced. The plates for contact detonation were loaded with 850 g PETN explosive at the test facility of the German Armed Forces Technical Center for Protective and Special Technologies.During the contact detonation a pressure wave runs through the plate and is reflected as a tensile wave at the free surface, opposite to the loaded surface. This tensile wave generates a damage crater on the rear side of the plate. The volume as well as the surface of the crater is determined by Impact-Echo tests, by 3D-scans and by measurements of the crater geometry.One target of this project is to work out a semi empirical formula for the determination of the crater volume and its surface in dependence on the main input parameters in order to provide a mobile application for the soldiers in charge of the infrastructure during a mission. The input parameters for this formula include amongst others the compressive strength fck, the bending tensile strength fct, the fiber geometry and the fiber content.This publication focuses on the conduction of the contact detonation tests. Furthermore, a mathematical approach for numerical analysis is presented.