Hot paving across the entire road width.

BOMAG pavers and feeders in action.

The B13 is one of the longest federal roads in Bavaria. It runs from the foot of the Alps to the River Main and connects the state capital, Munich, with the old episcopal city of Würzburg. The section passing through the village of Rupertsbuch, with around 500 inhabitants, was last resurfaced in 1990.

Now, the section in the Eichstätt district was due for an update. The experts in asphalt road construction from Pusch Bau GmbH & Co. KG were entrusted with the task. The binder course and surface course were paved "seamlessly" using three BOMAG pavers.

Staggered paving.

Longitudinal or centre joints can be weak points in the road surface because the individual lanes are only laid against each other. If surface water penetrates the road structure here, then freezes and expands, the damage caused by the daily traffic load and constant changes in weather takes its course.

However, longitudinal joints can be avoided with “hot to hot” paving on asphalt roads. Although the advantage of “no joints” can also be achieved with a sufficiently wide screed, two pavers of the same type were used in the Upper Bavarian town of Rupertsbuch. The reasons: the winding route through the town and two consecutive traffic islands just 280 metres apart. Having to dismantle and then reassemble a screed extension twice in quick succession contradicted the requirement for continuous, uninterrupted paving. What’s more: one side of the traffic islands would have been inaccessible.

A paving speed that is as constant as possible is a decisive factor when the requirements for surface texture and evenness are particularly high and if a uniformly high level of pre-compaction is also to be achieved. This generally applies to all asphalt layers and especially when laying temperature-reduced asphalt binder and surface courses in unfavourable weather conditions. Jan-Philipp Lay, Application Manager BOMAG

Requirements for “hot-to-hot” paving:

Continuous and uninterrupted installation must be ensured.
Pavers of the same type are to be used.
The installation speed of the paving trains must be identical.
The distance between the paving trains may not exceed one paver length.
The screeds should overlap by between 15 and 20 cm.
Before the first roller pass, the layer thickness and compaction conditions of the paving strips must be the same.

A BMF 2500 optimises the material flow efficiently and reliably.

The use of a feeder can also significantly improve paving conditions and paving quality. In Rupertsbuch, a short version of the BOMAG BMF 2500 was equipped with a swivel belt so the parallel pavers could be continuously supplied with mix. In this configuration, the swing belt's maximum swivel angle is 55°. With a BMF 2500 feeder, the machine operator benefits from a perfect overview in every work situation thanks to an individually adjustable workstation with a lift platform and swivel seat – both to the front when unloading the lorries and to the rear to feed the receiving hoppers of the pavers cleanly.

BOMAG's BMF 2500 also features a distance sensor to maintain a safe distance from the paver. The asphalt feeder's travel speed is automatically adjusted to match the paver's speed. Precision paving, no waste. The BMF 2500's bunker can pre-buffer an entire articulated lorry load. The 1.2-metre wide conveyor belt enables a transport capacity of 4,000 tons per hour and a truck unloading time of just 35 seconds for 27 tons.

Experts in asphalt road construction.

The production and delivery of the paving material could be offered and handled in-house, as Pusch Bau GmbH & Co. KG is a subsidiary of the owner-managed Geiger Group. This also includes the two mixing plants of IAM Ingolstädter Asphaltmischwerke GmbH & Co. KG and a fleet of over 60 vehicles.

The company Pusch Bau GmbH & Co. KG employs 120 people and sees itself as a powerful partner in road construction. Its clients include motorway agencies, road construction authorities, district offices and many towns and municipalities throughout the region: from Munich to Nuremberg, and Augsburg to Regensburg. Their nearest “own” mixing plant was 40 kilometres away, and 16 lorries circulated between Großmehring and Rupertsbuch.

Pavers and rollers round off the yellow fleet.

A BOMAG feeder, a BOMAG compact paver and several BOMAG tandem rollers have long been reliable components of the fleet. However, the BF 300 C-2 only needed to provide support at the very end of the 1,071-metre-long job site, as the road became wider and wider over the last few metres towards the junction with the 2047 state road. The bulk of the paving work was carried out by two pavers of the same type from the Universal and Highway class: the BOMAG BF 700 C-3 and BOMAG BF 800 C-3. The team from Pusch Bau GmbH & Co. KG also received on-site support from a BOMAG application expert, because paving is teamwork, and perfect quality and maximum efficiency in asphalt road construction requires the smooth interaction of many factors.

Advanced Pave is the name of the system that makes all machine and process-relevant functions transparent at a glance on BOMAG pavers while simultaneously allowing quick access to the settings. A levelling controller, material calculator, assistance and automatic functions provide information on the most important working modes – at every stage of the paving process. All key machine settings, such as crown profile, tamper frequency, vibration and path meter, are quickly comprehensible thanks to a simple and clearly structured graphical display.

The ability to configure the parameters for the upcoming site conditions on the side-mounted control panel with just a few clicks helped the paving team right from the start. The team at Pusch Bau GmbH & Co. KG was able to achieve the best paving results and high pre-compaction values immediately with their – for them – new machines. After all, the higher the pre-compaction, the more efficient the whole paving process. The pavers equipped with BOMAG's high-performance screed also did an excellent job in Rupertsbuch.

With a BOMAG paver, the high pre-compaction values can be achieved due to the screed's high dead weight in combination with the great depth of the screed plates. The target values were already easily achieved the day before when a top layer of warm mix asphalt was paved at another site.

What also stands out: BOMAG screeds work particularly quietly and heat up very quickly. On this morning, the pavers were ready to go after just 25 minutes. Thomas Sattler, foreman at Pusch Bau GmbH & Co. KG

The trailing BOMAG rollers then ensured perfect compaction results and the longest possible service life of the new road surface. In Rupertsbuch, the Pusch Bau GmbH & Co. KG team used several machines from the BW 174 AP-4 series. These heavy pivot-steered tandem rollers make it possible to achieve the required compaction results quickly – with a minimum number of passes. BOMAG road rollers can be used efficiently and economically on all modern rolled asphalt materials – even on warm mix asphalt. Depending on the model, they are available with different vibration systems: with classic double vibration as in Rupertsbuch, but also with oscillation and with ASPHALT MANAGER, which automatically and continuously adjusts the amplitude to the current compaction degree.

The temperature reduction of 20 °C contributes significantly to saving CO2 and improving working conditions during paving. We have the machines to meet the challenges of paving warm mix asphalt. Michael Witsch, Product Manager Paver BOMAG