Feldkirchen Graz/AT

Initial situation

On the A2 in Austria at Feldkirchen (Graz/AT) a 50m stretch of the right-hand lane had to be repaired. To minimise disruption of traffic on this important stretch the lane could only be closed at night.

Solution and assessment

For this project the rapid-hardening concrete Concretum^® Q-FLASH 2/20 was used. It reaches a compressive strength of approximately  20 N/mm² just 2 hours after the start of mixing. As the open time and consistency were adapted to the basic conditions (temperature, approach access, time and type of pouring) it was possible to lay the rapid-hardening concrete with a slipform paver in just the same way as conventional concrete. This is a real innovation. It was the first time in the world that rapid-hardening concrete was installed using a slipform paver. This increased degree of automation allows a stage performance which is far superior to manual pouring. Paving the 50m long and 3.5m surface took just 90 minutes and the entire construction process from the start of the closure until reopening in the morning took just 7.5 hours.

The knowledge acquired in this paving process represents a milestone in establishing the pouring of Concretum^® Q-FLASH 2/20 rapid-hardening concrete with slipform pavers for traffic surfaces.