An airport was doing maintenance work on its runway. The work could only be during the night because the track had to be operational in the morning. It was necessary to remove damaged slabs, reposition a new concrete slab respecting the flatness with others, then grout under it and the morning after the planes were able to land safely. Dimension of each slab was 16m x 7m + 0.60m and weight 300 tons.
We ensured leveling slabs with pneumatic jacks. These lifting bags were positioned under the new slab and allowed, according to the inflation pressure, to level the new slab. Furthermore, the air jacks were used in order to obtain a tigh space where grout could be injected. They were then removed and could be reused.
The materials of the inflatable jacks were carefully selected based on environmental constraints (anti-puncture, side inflation, strength..)
Their design allows over 50 uses. The installation tolerances are about 1 mm.