Abstract

Tunnels and underpasses are indispensable for the infrastructure and represent significant structures for the individual road traffic and the economy. An appropriate illumination of the traffic area (e.g. road surface and tunnel wall) is the most efficient contribution, not only to the safety, but also to the running costs of the tunnel. Brightness and light distribution in tunnels are not only influenced by the type and the performance of lighting, but also to a large extent by the optical properties of the road surface and the tunnel walls (i.g. brightness, reflectivity and degree of contamination). Therefore an appropriate choice of the building materials in terms of their optical properties is, beside the traditional material characteristics, essential

The goal of the research project was the examination of the effect of different materials for the road surface (e.g. concrete, asphalt) and the tunnel walls (e.g. different tunnel coatings) considering different levels of surface soiling on the lighting quality and the energy consumption of tunnel constructions. For realistic values of the lighting coefficients different and currently used tunnel constructions were examined. Three soiled tunnel constructions of different ages were chosen and their photometrical characteristics were determined before and after the tunnel cleaning.

Using concrete pavement in tunnels leads to better illumination of the road surface as well as the tunnel walls. The good photometrical characteristics of concrete, especially when using the additive titanium oxide, results in an increase in brightness of the road-surface and the tunnel walls. This improves the individual sense of security and decreases the energy input for lighting.

Keywords: Concrete roads; Pavement; Tunnel safety; Energy-saving; Illumination; Brightness; Shotcrete; Company Junger; Broll