When closing the gap on the German A26 motorway by new construction of a section near Stade in the Hamburg area, NAVITRONIC® Plus, the 3D Machine Control System offered by VÖGELE, performed excellently from all points of view. Papenburg-based German contractor Bunte was on the scene with a SUPER 2100-2 to pave asphalt base. Working without tensioned wires, the SUPER paver cut costs considerably and boosted productivity.

On this job site, contractor Bunte was faced with challenges which even for a large road building company were out of the ordinary. Not only was the asphalt base to be placed in a width of 10m without joint and a layer thickness of 18cm, in terms of evenness highest accuracy was specified, too. The demands were high as the project required a perfect base onto which to place binder and wearing courses “hot on hot” without any further grade and slope control. For the people responsible at Bunte, it was quite clear right from the start: for construction of the 10km section on the A26 motorway, NAVITRONIC® Plus, the 3D Machine Control System from VÖGELE, should be used.

SUPER 2100-2 with Fixed-Width Screed paves 10m wide asphalt base

As far as machine technology was concerned, Bunte opted for their large VÖGELE paver, a SUPER 2100-2. With its laydown rate up to 1,100 tonnes/h and a maximum pave width of 13m, this machine was the ideal candidate for the prestigious task. The SUPER 2100-2 was combined with a SB 250 Fixed-Width Screed in TP1 version, which is ideally suited to paving jobs in large, fixed widths and produces excellent pavement results in terms of evenness.

Due to the fact, however, that NAVITRONIC® Plus is a real 3D System for control not only of grade and slope but also of the screed’s position and the paver’s direction of motion, a certain flexibility is required for the screed to allow adjustment in width. For the SB 250 Fixed-Width Screed, this requirement was met by mounting a hydraulic bolt-on extension on either side. This way, a variation of screed width by 0.75m was easily possible on the left and on the right. Configuring NAVITRONIC® Plus with a Fixed-Width Screed and paving in 10m width received a premiere on this job site. As everybody had expected, both contractor Bunte and NAVITRONIC® Plus mastered the challenging task with distinction.

Cost-efficiency is the target

As earthworks and the water-bound base had been carried out using 3D machine control systems, meanwhile common practice on large-scale projects, it was a logical step for contractor Bunte to further benefit from their capital investment and use the existing survey data for asphalt paving as well. NAVITRONIC® Plus eliminates the need for time and cost-consuming tensioning of wires, thus saving contractors lots of money.

NAVITRONIC® Plus equipped for flexible use

NAVITRONIC® Plus comes with an open interface, so that positioning systems of different makes can be connected. As for earthworks on the A26 motorway project equipment made by Topcon had been used, it suggested itself to also dock a Topcon mmGPS+ positioning unit with the paver’s NAVITRONIC® Plus system. The Topcon unit combines satellite-based and laser-based measurements, allowing to calculate the machine’s location with the high millimetre accuracy required in road construction. The results are transmitted from the Topcon unit‘s computer to VÖGELE’s NAVITRONIC® Plus.

Fully automatic control of the screed’s position and the paver’s direction of motion

At this point, NAVITRONIC® Plus takes over full control of the machine. In the event of deviations in terms of layer thickness or slope, signals are emitted to NIVELTRONIC® Plus, the System for Automated Grade and Slope Control, and corrections are initiated automatically. Minor deviations in terms of screed position are corrected by NAVITRONIC® Plus through the screed’s hydraulic bolt-on extensions. In the event of major deviations and in bends, NAVITRONIC® Plus intervenes in the paver’s steering, thus locating both tractor and screed in compliance with the specified course of the route. It is this fully automatic control of both the screed’s position and the paver’s direction of motion that makes VÖGELE NAVITRONIC® Plus unique in the market.

Continuous paving thanks to VÖGELE Mobile Feeder

To ensure a sufficient supply of the large SUPER 2100-2 with mix at all times, a VÖGELE MT 1000-1 Mobile Feeder was on the scene, too. This way, continuous paving was guaranteed throughout the project with laydown rates between 3,500 and 4,000 tonnes a day. Due to HAMM’s excellent compacting technology, represented on this job by rubber-tyred rollers and DV 90 rollers with oscillation, the final density of the asphalt base was achieved in just a few passes.

Fewer working operations + less time = lower costs

Thanks to the team work of all factors involved on the A26 motorway, an asphalt base of high perfection was built. The roadbase fully meet the specified accuracy. As to the period of time needed for construction, the job was brought to completion far ahead of schedule. Compared to the specified duration of 6 to 8 weeks, it took the paving team no more than roughly 5 weeks to get the task done. A gain of time which Bunte could invest in other paving jobs.

Much impressed by the overall result, contractor Bunte made an immediate decision to buy NAVITRONIC® Plus for their equipment pool. According to Jan Hakenes, mechanical engineer at Bunte, the saving of costs was crucial. “Using NAVITRONIC® Plus eliminated the installation of reference wires over 10km, in other words, one less working operation. What is more, NAVITRONIC® Plus in conjunction with mmGPS+ resulted in increased productivity. All that was an improvement on the credit side”, engineer Jan Hakenes said. And he sums it up: Fewer working operations + less time = lower costs.

New A26 motorway between Drochtersen and Hamburg

The new 50km long motorway is designed as a four-lane link between Drochtersen and Hamburg via Stade and Horneburg. The motorway will replace part of the B73 Federal highway.

Construction work on Section 1 from Stade to Horneburg began in 2002 and will be completed in 2008. A decision on construction of Section 2 between Horneburg and Buxtehude was made in 2004.

In the south, in the Hamburg area, the new motorway meets the A7. In the north, it will later on be linked with the A20 also planned for the region.