Team of Four Paves "Hot to Hot"
VÖGELE pavers on the job at Frankfurt-Hahn Airport, Germany.
The former German military airbase Frankfurt-Hahn has been used as a civilian airport since 1993. Now coping with an immense traffic volume, the runway urgently needed rehabilitating. Six VÖGELE pavers and numerous other machines from the WIRTGEN Group completed this task flawlessly in an impressive round-the-clock operation.
In just a few years, Frankfurt-Hahn has become an important international commercial airport and the fifth-largest cargo hub in Germany. However, some 40,000 flights per year and last year’s harsh winter have left their mark on the runway. An initial section of the runway was thus rehabilitated back in April while the Icelandic ash cloud held air traffic in check. In September, no less than six VÖGELE pavers were deployed in order to finish the rest of the runway. The airport company itself also set its sights high: during the break in air operations, the company planned to replace the navigation beacons, carry out work on the drainage system and repair the edges of the runway. And all of this had to be completed more or less simultaneously.
Precision work at maximum speed
High-precision work at maximum speed was the order of the day, as the plan was to minimize disruptions to flight operations despite the many construction projects. The contract for rehabilitating 65,000m² of runway was awarded to a consortium comprising the contractors Bopparder Asphaltbau, Thomas Bau, Faber GmbH and Asphaltbau Hunsrück. They had no more than three days, or exactly 67.5 hours, in which to complete the job. This called for more than just working around the clock in shift operation. Numerous operations also had to be carried out simultaneously. Maximum concentration by everyone involved and perfect logistics were absolutely imperative, as some 150 to 160 people were working on the job site during peak times.
Impressive fleet with six pavers
The fleet of machines deployed for the project was impressive. Seven milling machines, six pavers and a host of rollers were used for asphalt paving alone. Furthermore, there were numerous feed lorries for the supply of mix, plus the vehicles from those companies tasked with the other construction projects. The first to get going were the seven WIRTGEN milling machines, which removed the wearing course and binder course to a depth of 14cm. The milling machines were given a four-hour head start in order to prepare enough of the runway for asphalt paving. This allowed the first four pavers to set to work while the milling machines were still busy on other sections. Two SUPER 2100-2 worked hand-in-hand with two SUPER 1800-2.
High Compaction Technology
All four machines came with Extending Screeds in TP2 version, equipped with tamper and two pressure bars. The pressure bars are the systems installed to achieve highest precompaction. High precompaction of base course and wearing course is essential for a perfect pavement structure and, as a result, for a paving result true to line and level. At Frankfurt-Hahn Airport, a special advantage of the VÖGELE technology paid off: the high compaction systems can be switched on and off at the push of a button. This means that wearing course can be paved all without high compaction. As an alternative, the pressure for the pressure bars is infinitely variable between a maximum of 120 and a minimum of 50 bar.
Grade and slope control with VÖGELE multi-cell sonic sensors
Grade and slope control was a particular challenge as the runway had to be absolutely even and free of irregularities. Here the paver operators could rely on NIVELTRONIC Plus®, the VÖGELE System for Grade and Slope Control, which was combined with multi-cell sonic sensors. On this job site, these sensors referenced from the edges of the previously paved strips. The VÖGELE multi-cell sonic sensors are in a position to perfectly level out even short irregularities in the base. Equipped with high compaction screeds and multi-cell sonic sensors, the team of four pavers placed the new binder course and wearing course in strips, 5 to 6m wide, “hot to hot”. As work progressed, even six VÖGELE pavers were in operation in alternating teams. All told, they laid roughly 14,400 tonnes of mix for 9cm binder course and 8,400 tonnes of mix for 5cm wearing course.
Highest evenness even in the areas of joints
The permissible tight tolerance of ± 2mm over a distance of 4m could easily be met. The result was a pavement of impeccable evenness also in the areas of the joints, which were made to perfection. A great performance by the contractor’s team was completion of the job within the short period of time considering an amount of almost 23,000 tonnes of mix paved. “To lay such a large quantity of mix in just three days, everyone in the team must know exactly what they are doing,” commented Thomas Mayer, Site Manager of Bopparder Asphaltbau GmbH & Co. KG.
Work finished ahead of schedule
Of course, none of this would have been possible without sterling work by the fleet of all machines involved. Every minute, the feed lorries supplied fresh mix to the job site that was laid immediately. Two additional VÖGELE pavers and a number of HAMM rollers were on standby in case a machine failed, but were ultimately not needed as every machine worked excellently. “That’s why we were able to hand over the job site to the contracting authority one hour earlier than scheduled, despite the narrow time slot of just 67.5 hours,” added Thomas Mayer.
Job Site Details
Pavement rehabilitation of runway at Frankfurt-Hahn Airport, Germany
Length of section: 2.3km
Width of section: 45m
Pave width: 5–6m
binder course 9cm
wearing course 5cm
Binder course: AC 16 B S, PmB 25/55–55
Wearing course: AC 11 D S, PmB 25/55–55
6 WIRTGEN W 2200 Milling Machines
WIRTGEN W 100 Milling Machine
2 SUPER 2100-2 with AB 600-2 Extending Screed in TP2 Version
3 SUPER 1800-2 with AB 500-2 Extending Screed in TP2 Version
1 SUPER 1900-2 with AB 500-2 Extending Screed in TP2 Version
HAMM DV 90, DV 85, DV 70 and HD 14 VV Rollers