Low-temperature asphalt paved on a motorway section in Germany.

Approximate Temperature 130 °C

A SUPER 2500 was on the scene on the A7 motorway near Schleswig, Germany, when the contractor Eurovia built a 5.6km long section in record time. The stretch was declared a trial section by the Federal Ministry of Traffic and Transport (BMVBW) and the research project awarded to the German Asphalt Laboratory Hinrichsen (Prof. Damm). The Federal Road Research Institute (BASt) took part in the assessment of the trial section. For the preparation of low-temperature asphalt, five types of special binders were made available by different suppliers and submitted to the test.

   SUPER 2500 with SB 300 Fixed-Width Screed in TP2 Version.

A vital target of the research project initiated by the BMVBW is reduction of both CO2 and hydrocarbon emissions during construction or rehabilitation of road pavements. On the trial section investigations were made into the special mixes suitability for paving and emission measurements were carried out while placing the low-temperature mixes. The special binders put to the test on the A7 motorway were Sealoflex, Olexobit, Sübit, SMB and Caribit and the binder chosen for comparison was conventional PmB 45 A.

Like usual asphalt but not so hot
As to the mix, the contractor Eurovia used AB 0/16 S for binder course and SMA 0/11 S for wearing course, materials that had undergone testing for suitability by the German Asphalt Laboratory Hinrichsen. All five special binder products allowed a substantial reduction in temperature: instead of 160 to 170 °C usual so far for placing hot mix, the SUPER 2500 paved the mixes at temperatures of no more than 125 to 130 °C. Evaluations are still underway, but at this point of time it can already be said that in the wake of reduced temperature, notably reduced emission could be observed as well.

Achieving the specified final density was child’s play
In addition to eco-friendliness, compaction of the mixes was another criterion in the assessment of low-temperature asphalt paving. The BASt recorded the number of roller passes in order to identify the requirement for extra compaction. The quality of low-temperature asphalt paving was on a par with paving at conventional temperature. A total of 5 rollers were on site and reached the specified final density of 98% after 5 to 6 passes.

The SUPER 2500 paved in 9.5m width
The large pave width was a merit also of the SUPER 2500 used by the contractor Eurovia for building the trial section. According to its specification, the flagship of the VÖGELE fleet of pavers is capable of handling pave widths up to 16m and layer thicknesses up to 40cm, the latter depends on the quality of the mix and the method of paving. This results in a laydown rate of up to 1,100 tonnes/h. The SUPER 2500 is compatible with both VÖGELE Extending Screeds and Fixed-Width Screeds. Eurovia combined their paver with a HPC SB 300 Fixed-Width Screed in TP2 version. They built up the screed with two conventional extensions of 1.5m and 1m and hydraulic extensions of 0.75m. All in all, this made a pave width of 9.5m. The TP2 in the screed name stands for tamper and 2 pressure bars. These compacting systems achieve a high precompaction so that less extra compaction by rolling is required. On the trial section, Eurovia made use of this advantage also for paving wearing course.
Low-temperature asphalt reduces
emission.

 MT 1000-1 Mobile Feeder for a continuous supply with hot mix.


SUPER Help: MT 1000-1 Mobile Feeder
The VÖGELE MT 1000-1 Mobile Feeder was on site to back up the SUPER 2500 in its continuous, non-stop paving of the low-temperature asphalt. For a continuous paving process the feed lorry docks at the Mobile Feeder running in front of the road paver. A conveyor system transfers the mix into the paver’s material hopper, thus utilizing its holding capacity to the full. If even more mix needs to be stored, an extra hopper available in different sizes can be placed into the paver’s material hopper, which increases the storage capacity up to a total of 20 tonnes. But the MT 1000-1 Mobile Feeder offers to users a number of additional advantages. It extends the time interval between lorry changes without a need for the paver to stop due to lack of mix. Thanks to the Mobile Feeder, paver stops caused by a lorry change also are a thing of the past. And as another trump in the game, the feed lorry supplying the mix is no longer tied to the paver. Shocks like those known from lorries docking at the paver are eliminated and cannot have an adverse effect upon the quality of the pavement being laid.


Old turned into new in a couple of weeks
Before the paver moved onto the site, two WIRTGEN W 2100 milling machines removed the old pavement layers from carriageway and shoulder. The machines managed to mill off the 66,000m² of road surface in only three days. The paving train made up of the SUPER 2500 and MT 1000-1 Mobile Feeder did a quick job, too. It was due to the fast progression of overall operations on the A7 motorway that the project originally scheduled for completion after a couple of weeks, was actually completed two days ahead of schedule.