Night-time construction project: what passengers don't know
The BOMAG BF 800 C finisher gave an impressive performance on the redevelopment of the runway at the airport in Nuremberg. At night with impressive site lighting, the surface was renewed along a 2.8 km long and 15 metre wide section. The work was carried out from 11:00 p.m. to 7:00 a.m. on three weekends between the end of April and the beginning of July 2013. For this the contractor, the highly respected construction company W. Markgraf GmbH & Co KG from Bayreuth, used two BF 800 C finishers with an S 500 screed extended to 8 metres. For compaction the company used the tandem roller models BW 100 AC and BW 154 AP with ASPHALT MANAGER.
11:00 p.m.: the Nuremberg airport is an important hub for air traffic to and from the South of Germany. It is also one of the few airports without a ban on night flights. The airport's runway has a total length of 2.8 km. Since July 2009 the runway is being renewed and the width is being extended from 45 to 60 metres. This means that existing surfaces must be renewed, as well as the shoulder area expanded, including cable installations and beacons. To reduce the effects for air traffic as much as possible, the airport was completely closed for flight operations on six weekends between 11:00 p.m. and 7:00 a.m.
1:00 a.m.: After the concrete surfaces of the runway had been removed, the laying of low temperature asphalt started. Compared to other types of asphalt, low temperature asphalt can be mixed and applied at much lower temperatures. Additives in form of waxes or zeolites are added to the standard asphalt mixture, which allows it to be mixed and laid without compromising processing or performance. After laying the asphalt can be driven on at a temperature of 70 °C and for the work at Nuremberg this was the best solution to ensure fast release for traffic.
With this method, which is fast and economical for the airport operator, the time pressure on the construction company is high. At night Markgraf only had six hours when the flight operations were interrupted to lay the new surface, wait for the sections to cool and hand them over to the airport company ready for operation. Any delays were ruled out from the beginning, as a late hand-over would result in expensive penalties. “The specifications for this site were, of course, very high”, recalls site manager Andreas Völkl. “Renovating a runway is an tough project. It must be meticulously planned and everything must work perfectly. It goes without saying that it is always our aim to do a perfect job, but here we had absolutely no room for error. Planes had to be able to land safely on the runway again.”
2:00 a.m.: Surprisingly, despite the time pressure you could feel a relaxed atmosphere at the airport – unusual for such construction projects. The reason for this was – besides the experienced team working together in harmony – a paver they could rely on. Thanks to the generous dimensioned levelling plates made of high wear resistant steel and the optimum weight distribution, the high performance screeds on both BF 800 C finishers created a uniform surface structure and evenness – with no waves or indentations. On this site, too, the finishers ensured the usual high level of operational reliability, which was vital considering the high time pressure. A decisive feature in this was the MAGMALIFE heating system where the screeds have electric heating as standard. The heating elements are cast in an aluminium block making them highly durable. “The heat distribution is very good. The screed plates heat up fast – this was vital and we had no delays”, was Andreas Völkl's verdict. An contribution which helped the Bayreuth company to meet the high quality targets and tight schedule.
3:00 a.m.: Like clockwork, the base, binder and surface layers were laid at a speed of 5 metres per minute. Important for the operators on the night shift: the BF 800 C is extremely quiet and can be operated easily and intuitively. No stressed operatives, hectic activity or delays in Nuremberg. During the project, site manager Andreas Völkl, always kept the asphalt surface temperature required by the airport in mind. This was not allowed to exceed 70 degrees Celcius. “We needed absolute reliability for this project and thanks to both BF 800 C finishers and the following compaction work with the tandem rollers everything went without a hitch”, concluded Völkl.
7:00 a.m.: At 7:00 a.m. sharp, the quality inspection was carried out by the construction safety experts at the Nuremberg airport. Thanks to the BF 800 C finishers, Andreas Völkl knew what the tests of the airport construction safety inspectors would show: compaction levels, quality and evenness were all to specification. A few minutes after seven in the morning Völkl finishes a good night's work. “At 7:30 you see the first passengers streaming into the airport looking forward to a summer vacation and having no idea what we did here during the night. You can feel satisfied at your work.”