By Steve Skinner27 January 2009
A fleet of Bomag asphalt rollers including ten pivot steered BW174 and BW184 models have compacted 81000 tonnes of asphalt at Zurich airport in Switzerland over the past six months in a CHF 56 million (€ 37 million) project to reconstruction the airport’s ‘16/34’ runway – the longest of its three.
Strict operating hours and conditions were imposed on contractors so the airport could operate normally between the hours of 05.30 and 23.30, which left just six hours each night to remove sections of the runway, lay pipes and install a new asphalt surface.
“The aim was to completely remove a 23 m wide 3700 m long central concrete strip during night time hours, taking it up and relaying it in 70 m sections,” said Ueli Stalder, construction engineer for contractors Walo Group.
“The specification was extremely high, but such was the experience of the team and the quality of the equipment, we were able to reduce the original three layers of asphalt base down to a single 250 mm layer, while maintaining a 98% compaction as specified,” said Mr Stalder.
“Many tonnes of low temperature asphalt (stipulated by the airport not to exceed 800 C), held in temporary storage at the airport, were spread using dozers and then compacted in eight passes by the Bomag rollers. Compaction was then followed by a 100 mm asphalt binder layer.
“Bomag Asphalt Manager completely won us over in the tough conditions,” said Mr Stalder. “With growing experience, the crew was regularly able to complete section lengths of 70 m, whereas when we first moved on site we were laying 30 m,” said Mr Stalder.
“The preparations alone for this construction site took months,” said Mr Stalder. “Consequently, the coordination of multiple, closely interlinked work phases were tried out on a test site before we even arrived at the airport.”