InLine Pave® Train Widens Highway While Open to Traffic
Paving asphalt “hot on hot” on the B 50 federal highway in Germany
The innovative VÖGELE technology permitting the paving of binder and surface courses in a single pass is becoming the method of choice on ever more job sites when it comes to cost-efficiency and quality. An InLine Pave® train from VÖGELE was also used to widen the B 50 federal highway from two lanes to four – giving the system a perfect opportunity to demonstrate its strengths to a delegation of reputed experts in the field of asphalt paving.
The B 50 federal highway is an important arterial road for the Hunsrück region. “This east-west axis is of tremendous importance to the economy and the traffic infrastructure, especially for the southern Rhein-Hunsrück district and as a link with Frankfurt-Hahn airport. It also serves as an internal link to the ports at Antwerp and Rotterdam”, said Achim Großmann, Undersecretary to the Federal Minister of Transport. “I’m very pleased that we’re upgrading the B 50 to a four-lane highway and that the work is progressing so well.” Roadworks on the B 50 between the A 61 motorway and Frankfurt-Hahn airport are scheduled to be fully completed by the end of 2011.
High-quality paving thanks to “hot on hot” process
One section of the roadworks was located between the Büchenbeuren and Nieder Kostenz junctions. On this 7.3km stretch, contractor Wilhelm Faber GmbH & Co. Bauunternehmung KG, tasked with the job, used the InLine Pave® train, an economical option for compact asphalt paving in a single pass. The innovative VÖGELE concept for “hot on hot” paving involves three machines: the MT 1000-1 Mobile Feeder, a SUPER 2100-2 IP for paving binder course and a conventional machine for paving surface course – in this case a SUPER 1600-2. The SUPER 2100-2 IP, a slightly modified standard paver with a special transfer module for the surface course mix, is the InLine Pave® train’s central element. The paver’s AB 600-2 IP High Compaction Screed already produces outstanding precompaction results with the binder course. This means that even a surface course paver weighing some 40 tonnes, such as SUPER 1600-2, can travel on the binder course, while still hot, without damaging it. And measurements taken on the Hunsrück job site proved that this is not merely theory: the inspection record showed that, for the binder course, the average degree of final density was exceptionally high at 101.6%.
Asphalt experts observe the roadworks
The use of the InLine Pave® process in the Hunsrück region was a matter of keen interest among asphalt experts. Consequently, the laboratory commissioned with conducting the inspection, Chemisch Technisches Laboratorium Heinrich Hart GmbH, visited the job site. The company has earned a worldwide reputation through advising race circuit owners on choosing the right type of asphalt and paving process. The site was also visited by Prof Karl-Ludwig Scholl, Director of the Official Test Centre for Road Construction Materials and Recycling at Koblenz University of Applied Sciences. Professor Scholl is convinced of the advantages of “hot on hot” paving, which is characterized by a relatively thick binder course and a relatively thin surface course. Both layers are paved in a single pass, resulting in a perfect bond between the layers on account of excellent interlocking. Thanks to this process, the high-quality – and thus more expensive – surface course material can be used more sparingly and economically. Prof Scholl said: “I’m particularly interested in VÖGELE machine technology because it operates on the basis of what is more or less standard equipment.” This in turn reduces the capital investment for contractors, as they can also use all three machines of the InLine Pave® train for conventional paving jobs at any time.
Different types of mix and layer thicknesses
The InLine Pave® train laid various types of mix in different layer thicknesses on the B 50. On the first job site section, 6cm binder course was paved using mix of the type AC 16 B S (25/55-55 A), whereas on the second section, mix of the type AC 22 B S (25/55-55 A) was placed for 10cm binder course. On both sections, the surface course of Stone Mastic Asphalt type SMA 8 S (25/55-55 A) was 2cm thick. Each day, some 2,000 tonnes of mix were paved on a stretch of 1,500m.
Paving team looks forward to InLine Pave® jobs
Since the paving team of contractor Faber had already successfully completed a number of jobs with the VÖGELE InLine Pave® train, the roadworks on the B 50 were pretty much a routine affair. “Our team manages wonderfully with the InLine Pave® train and always looks forward to using it”, said Thorsten Müller, Operations Manager at Faber. Grade and slope control was also outstanding: a multi-cell sonic sensor tracked the kerbstone on the first job site section and the freshly paved left-hand lane on the second one. The sensor provided accurate measurements for NIVELTRONIC Plus®, the System for Automatic Grade and Slope Control, so that achieving the specified evenness of ≤ 4mm measured over 4m was child’s play.
Efficient HAMM HD+ 140 roller with impressive performance
The new HAMM HD+ 140 VO roller, equipped with vibration and oscillation, did an excellent job to produce the specified final density. Thanks to its outstanding compactive effort and performance, it required just two passes to finish the task. The roller manoeuvred up to the paver with oscillation mode activated, while compacting in static mode on the return pass. This 14-tonne class roller has roughly the same static linear load as a 9.5-tonne roller, but wider drums (2,140mm). The maximum working width in crab steer mode is 2.3m. In addition to the HD+ 140, a DV 90 and a DV 70 roller from HAMM also ensured that the degree of density specified for the Hunsrück job was achieved quickly and reliably.
Job Site Details
Widening of the B 50 federal highway from two to four lanes with InLine Pave®
Length of job site: 7,300m (per lane)
Width of job site:
1st section 5.8m
2nd section 4.5m
Total area paved: 75,200m²
Pave width: 4.5 – 5.8m
Binder course 1st section 6cm
Binder course 2nd section 10cm
Surface course: 2cm
1st section AC 16 B S (25/55-55 A)
2nd section AC 22 B S (25/55-55 A)
Stone Mastic Asphalt SMA 8 S (25/55-55 A)
VÖGELE InLine Pave® train comprising:
MT 1000-1 Mobile Feeder
SUPER 2100-2 IP for binder course with AB 600-2 IP Extending Screed
SUPER 1600-2 for surface course with AB 500-2 TV Extending Screed
HAMM HD+ 140 VO, DV 90 and DV 70 Rollers