Cat paver chosen for Swedish runway project
AP600D asphalt paver selected by Peab Asfalt for airport resurfacing work
Peab Asfalt of Sweden primarily handle major road and highway projects in the inland portion of the country. But the company was willing and able to take on a new challenge when the runway at Jonkoping airport needed to be paved.
Reijo Seppanen, project superintendent for Peab Asfalt, said: ‘When you’re working on a project like this, anything can happen. You can have problems with the weather and there are always time pressures, deadlines to meet. We have to get off the runway one hour before the next airplane is arriving.’
Jonkoping is a relatively small airport but still crucial to the inland area of Sweden. Flights typically were rerouted during the project, with the exception of two per day in the late afternoon or evening. That allowed Peab Asfalt to make progress almost daily, and also kept outbound and inbound passengers and freight connecting to key hubs in Stockholm and Copenhagen.
Even with limited flights, paving schedules had to be adjusted. Paving often started in the middle of the night and extended into the late afternoon of the following day.
Another contractor handled the first phase of the project, which consisted of milling about 50mm off the existing surface. The paving portion of the project took about three weeks.
Segregation is always on the mind of Seppanen and others at Peab Asfalt. The efforts start at the plant, with proper loading of trucks. The trucks themselves have rounded-, not flat-, bed bottoms. This prevents sticking when the material is end-dumped into the Cat AP600D later in the process.
The trucks travelled about 70km (43 miles) from the plant to the airport. Traffic was light given the area and the fact much of the paving was done at night. Shorter truck cycle times, combined with other segregation efforts, paid off.
‘Our trucks are insulated, so the asphalt stays hot,’ said Mr Seppanen. ‘The asphalt is covered as well. There was no problem keeping the asphalt in the trucks hot because the job took place in the middle of the summer.’
The mix left the plant at 170-180oC and was dumped into the hopper at about 160-165oC. Plant production, paving speed and trucking were all calculated to keep the paver moving at a consistent pace.
Another segregation technique is allowing mix to collect in the sides of the hopper throughout the shift. Paeb Asfalt don’t close the (hopper) sides between lifts to loosen material. The asphalt on the sides is cold, and so they don’t want to shake it loose and mix it with the hotter material. When the work is done for the day, then the sides are cleaned.
The AP600D was a newcomer to the site, with the company previously using a different manufacturer’s product.
The paver worked at a pace of about 4-5m per minute, placing a single lift of 40mm. The Cat paver worked at a width of 4.5m and 10 passes were required to cover the entire width of the 45m runway.
The width of the project led to a number of longitudinal joints. Peab Asfalt crews placed the new, hot mat slightly higher than the adjacent cold mat. A breakdown compactor was used with a small side roller to compact the joint.
Three heavy 11-tonne rollers handled compaction.
The first roller made six to seven passes, with a movement up being one pass, and the movement back counted as a second pass. The second roller worked about 50m from the paver. The number of passes varied based on that day’s conditions. The compactor was vibrating while making its passes. The third roller had no set distance between it and the rest of the paving train and was used to take the tracks out of the mat and make it smooth.
Core samples were taken along the way to ensure adequate compaction was being achieved.