Bridge superstructure SBB, Remisenstrasse Zurich

Situation

At Remisenstrasse in Zurich, a cast-in-place concrete trench had to be constructed to connect two bridge elements over the Swiss Federal Railways (SBB) tracks. To pour the joint closure and install the pipes under the bridge, the tracks were closed and the overhead lines were deactivated. The closure periods for SBB needed to be kept as short as possible. The fact that the project fell during a period when air temperatures were around freezing added further challenges for optimal concreting conditions.

Solution and Evaluation

To meet these challenging conditions, the engineer opted for the rapid-hardening concrete Concretum^® Q-FLASH 2/20. The concrete was produced directly on-site in a concrete mixer truck and poured using a crane bucket. Concretum's specialists were able to precisely control the open times of the rapid-hardening concrete by accurately adding the calculated amount of special retarders and plasticizers, ensuring that the setting process for the staggered concrete mixer productions began at exactly the same time.
Despite temperatures around 0°C, the hydration of the high-tech concrete proceeded as planned, and the pipes were installed after 2 hours. This allowed the tracks to be reopened for SBB in a very short time.