Renovation of ASTRA Tunnel Taubenloch N16 - T3

Project

The measures in the Taubenloch Tunnel near Biel focus on the renovation of the retaining arch, as well as the north and south portals, and ensuring the tunnel’s traffic conditions.

The work includes reinforcement measures for the rock, arch renovation, bank repair with the integration of BSA facilities in the tunnel, installation of new piping and drainage systems, renovation of the north and south portals, as well as the restoration of the pavement box and pavement.

During the renovation work on the structure, the tunnel must remain open for traffic during the day. Therefore, the work is carried out at night to ensure that the road is restored with two lanes by morning.

Special concrete requirements

The Concretum^® Q-FLASH 2/20 self-compacting concrete was adjusted in preliminary tests to ensure that it distributes well throughout the entire tunnel formwork and can be easily pumped. Additionally, the setting process of the rapid-hardening concrete was set to three hours. The concrete sets quickly, even as SCC, and reaches a strength of about 20 N/mm² one hour after the start of the setting process.

Customer benefits

This pilot project initiated by ASTRA provides insights for the client into:

• Form stripping times with rapid-hardening concrete
• Advantages in time savings vs. additional costs
• Quality of rapid-hardening concrete vs. conventional concrete
• 24-hour shifts – formwork can be reused multiple times, and several stages of concreting can be completed

For the trial, Vigier Beton AG supplied 96 m³ of rapid-hardening concrete in three stages to the N16 – T3 tunnel construction site.