In the absence of daylight, subway stations quickly become dark and spooky places. The planners of the new Karlsruhe Metro, the Munich office of Allmann Sattler Wappner Architects, wanted to counter this effect by the choice of suitable materials: façades and floors will be executed in light architectural concrete based on white cement. Both the façades and the platforms in all seven newly erected stations will be implemented in large-dimensioned cast-stone panels, manufactured by the company Schwab-Stein of Horb, Germany. The panels for the façades were manufactured based on Dyckerhoff Flowstone. Dyckerhoff Weiss Zement was used as binder for manufacture of the floor panels and platform edges; for the rest, the mix design was nearly identical to the wall panels. Most panels have a width of approx. 100 cm and a height of 50 cm.
For the flooring on the intermediate levels of five of the seven stations, the Dyckerhoff Terraplan concrete floor system was chosen. The concrete for this system is produced on the basis of Dyckerhoff Weiss in a ready-made concrete plant and is delivered to the construction site on a truck mixer. For the optical impression of a Terraplan floor, the individually selectable aggregate is very important; in Karlsruhe, the planners decided on Rhine gravel, which is typical for that region. The works were executed by the company R. Bayer Betonsteinwerk from Blaubeuren, Germany. On the cast stone used for this infrastructure project, maximum requirements are placed in several regards. The color shade of the concretes and the constancy, the abrasion resistance, the skidding resistance, the dimensional stability and the fire protection of the wall cladding are the criteria that must be satisfied and consistently implemented. Prerequisite for this are the superior basic qualities of the concretes cast with the binder Dyckerhoff Flowstone on the one hand, and the pressed large-dimensioned panels made with Dyckerhoff Weiss as binder, on the other. The unfinished products made in this manner, in combination with state-of-the-art processing of cast stone, meet the architectural demands of this project with all its planning requirements.