C. Frey’s scientific contributions

Military facilities, buildings such as embassies or nuclear power plants must be protected against effects and impacts from terrorist attacks or accidents. In the course of new building or upgrading existing structures the protective function against gun fire or debris due to explosions should be fulfilled with small dimensions. The main material property influencing the resistance against these threats is the tensile strength. By adding steel fibers post-cracking behaviour and ductility of components can be improved. A new type of steel fiber has been tested for application in construction elements under high loading rates. Protection shields have been produced and the effect of small caliber gun fire has been investigated. The tests on concrete shields showed a considerably reduced crater dimension and reduced raptures. By using steel fibers the endangerment of persons and facilities by debris can be reduced. With the tests the positive influence and the fundamental suitability of the new long fibers could be confirmed. A possible application would be the usage for barriers or modular systems made of precast concrete or hardening of existing structures. Keywords: steel fiber, protection shield, small calibre gun fire.