The section on runway 10/28 at Zürich Airport had several damaged slabs with an area of between 20 m2 and 90 m2. On account of the narrow repair window, it was important for concreting works to take place during the night. In a timeframe of approximately seven to eight hours, the concrete slabs were broken with heavy machinery and then reinforced and poured with rapid-hardening concrete. The objective was to be able to resume flights at the latest by 5:30am.
Solution and assessment
In this project, the rapid-hardening concrete, Concretum® Q-FLASH 2/20, was used which reaches a compressive strength of approximately 20 N/mm2 just two hours after the start of mixing. The concrete produced, in particular, the volume of concrete from the plant, was adapted to the extracted slabs so that it could then be placed and spread using a power shovel.
The open time of the concrete was modified at the plant in accordance with the contractor’s specifications. In this way, the window for installation and the time when the concrete starts to set could be specified precisely.
Finally, the concrete reached the required strength of > 16 N/mm2 by 5:30 am and the runway was opened to aircraft traffic.
Concretum® Q-FLASH 2/20
Implenia AG, Zürich