Influences on the Characteristics of Concrete through the Application of Polypropylene Fibres to increase the Heat-Resistance of water-impermeable Inner Shells

By adding 2 kg/m3 polypropylene fibres a spelling of the concrete for inner lining can be avoided reliably in tunnels even under the extreme condition of a fire. The fibres change the characteristics of concrete. The characteristics for an installation of reinforced inner shells especially are negatively influenced. In the article at hand the conclusions of lab experiments are explained. After a practical testing the concrete has been successfully employed at a construction site in Vienna. In addition, details for influencing factors that have to be observed are given.