Impermeable concrete is being used by contractor Meier & Jaggi to save on waterproofing on an 8.75m double bore cut and cover railway tunnel in the Swiss Emmethal valley.
Concrete for the new 890m Thunsetten tunnel is produced using the 'whitetank' method which uses warm water, anti-freeze additives and insulated curing covers. Crack inducers at 6m centres minimise random cracking. Acrylic resin is injected into the induced cracks to form a final seal.
The Thunsetten tunnel is one of four stretches of tunnels on a 46km section of new line for national Swiss rail operator Schweizer Bundesbahn's (SBB) Bundesbahn 2000 project.
The project should cut journey times from many of the major rail routes in Switzerland, particularly between, Geneva, Bern, Basel and Zurich.