Intact transport infrastructure for the expansion of renewable energy generation

• The project in Obersontheim, Germany, involved the use of a Wirtgen Group Production System for road widening to support new wind turbine installations.

• The road was widened from 4.5m to 7m over a distance of 1,100m, with a cement-treated base layer (CTB) added.

• Key machinery included a Streumaster SW 112 TC spreader, Wirtgen WR 240i recycler, Hamm H 7i CompactLine compactor, John Deere 672 GP motor grader, and Hamm HC 130i compactor.

• The John Deere 672 GP motor grader's Auto-Pass function facilitated precise surface grading with minimal manual intervention.

• Despite challenging weather and a tight deadline, the construction phase was completed on schedule within two days.

The erection of new wind turbines in the Swabian Jura region is one of the measures contributing to the expansion of Germany’s renewable energy generation capacities. A well-developed transport infrastructure is essential for enabling access to sites and the construction of new power generation facilities. In the course of a construction project in Obersontheim, Germany, the contractor deployed a Wirtgen Group Production System made up of two Hamm rollers, a John Deere 622 GP motor grader, a cold recycler WR 240i from Wirtgen and a Streumaster SW 112 TC tractor-towed binding agent spreader.

Road widening with a cement treated base layer (CTB)

The project brief for the resurfacing of the access road to a wind park required the rehabilitation of the existing road with a cement-treated base layer (CTB) and simultaneous widening from 4.5 m to 7 m over a distance of 1,100 m. In the first step, a SW 112 TC tractor-towed spreader laid down the cement for the production of the cement-treated base layer.

Following on behind, a wheeled recycler WR 240i from Wirtgen, milled the base layer to a depth of exactly 35 cm and homogeneously mixed the material with 49 kg of pre-spread cement per square meter with its powerful milling and mixing rotor. Water was sprayed into the mixing chamber during the mixing process by means of an injection bar.

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Precision at the press of a button

Behind the recycler, a Hamm H 7i CompactLine compactor carried out the first pre-compaction pass before the John Deere 672 GP motor grader graded the pre-processed base layer material to a cross-slope of 3%. A particularly impressive feature of the Grader is the Auto-Pass function, which significantly simplifies precise surface grading. The press of a button places the grader mouldboard on the ground and activates the Grade Pro system. At the end of a pass, the mouldboard is raised again and turned to automatically replicate the desired grade value on the other side of the road. This means that the Grader no longer has to be driven back to the starting point to start all over again. ‘The automation offered by the Auto-Pass function was really useful, particularly here. Just one press of a button sets the cross-slope we need after turning the machine.’ says Heinrich Eichele jun., Managing Director of Gebrüder Eichele GmbH, expressing his satisfaction with the results. The subsequent final compaction was carried out by a Hamm HC 130i compactor.

Despite the unsettled weather and the tight deadline, the construction phase was completed on schedule within a period of two days.

The subsequent paving of the asphalt surface layer was carried out by a SUPER 1800-3i road paver from Vögele.

Project details

• Location: Obersontheim (Swabian Jura)

• Length: 1,100 m

• Width: widened from 4.50 m to 7.00 m

• Cement added: 49 kg/m²

• Working depth: 35 cm

• Cross-slope on each side 3%