Stringless concrete paving with the Wirtgen SP 25i and AutoPilot

Stringless concrete paving

German construction contractor “VSB infra” takes advantage of the benefits of AutoPilot 2.0 for the paving of a poured in-place concrete safety barrier.

In the future, the eastbound and westbound lanes of the A 43 Autobahn near the city of Münster, Germany, will be separated by a poured in-place concrete safety barrier. The effectiveness and permanence of such construction elements for the passive protection of road users makes them the preferred vehicle restraint system, especially on sections of roads with heavy traffic.

The monolithic profile will be paved by an SP 25i using the slipform paving method. The use of AutoPilot 2.0 on this project eliminates the need for the paving crew from VSB infra GmbH & Co. KG to set up a stringline for controlling the machine. They use the 3D control system whenever and wherever possible.

Automatic 3D control system

Developed by Wirtgen, the control system enables precise, stringless control of slipform pavers. As the system completely eliminates the time and effort usually required for setting up and removing a stringline for conventional machine control, it also reduces project completion times and costs. Instead of this, the machine is guided along a virtual stringline by satellite-aided navigation. This makes the entire workflow faster, more efficient and, in turn, more cost-effective. What’s more, it also makes the paving of complex geometries such as tight radii or in S-bends, significantly easier.

Kay Petersen, CEO of VSB infra GmbH & Co. KG

‘This is another project on which we are using stringless paving. We have been using the AutoPilot system since it came onto the market. It saves us so much time that we use it on both of our machines whenever we can.’

Kay Petersen, CEO of VSB infra GmbH & Co. KG

Working space and safety

As is typical for construction projects on major highways like the A 43 Autobahn, the working area offers very little room for the paving crew. Using a stringline in front of the machine in situations like this would limit this space even more. But you won’t find anything at all like that here! Not unless you take a look at what’s shown on the screen of the AutoPilot tablet. The hand-held control unit displays the course of the virtual stringline and provides precise information to the machine operator at every single point along the predefined track. This also means that there is plenty of free space in front of the slipform paver. Concrete mixers have room to manoeuvre and can drive right up to the paver to deliver their load. The free space in front of the machine brings the paving crew more room to work in and leads to greater safety on the project site. The absence of a stringline also removes the risk of tripping and injuries as a result of falls.

Graphic illustration of how AutoPilot works

Increases precision, saves time and cuts costs.

The AutoPilot 2.0 3D control system takes control of the production of all kinds of offset and inset profiles. There is no longer any need for a surveyor to create a geodetic data model in advance. Laborious surveys and the time and effort involved in setting up and removing stringlines are no longer required.


The team from VSB infra starts using AutoPilot before the actual construction work begins. Relevant points on the project site are recorded with the Field Rover survey pole and form the basis of the digital data model for the generation of the virtual stringline. This eliminates the need for an additional surveyor on the project site.

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The AutoPilot then takes control of the slipform paver. The machine then works its way along the predetermined virtual stringline with absolute precision. The existing sub-base of the A 43 is sampled by an ultrasonic sensor and used as a reference by the machine control system. The result of this is extremely precise paving of the required concrete profile.

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Quality assurance

The AutoPilot also plays an important role behind the machine. The Field Rover also enables extremely precise quality assurance measurements of the paved profile almost in real-time.

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Maike Teuwsen, Site Manager

‘Thanks to the Field Rover, I can perform a quality check on the paving results right behind the machine. I also really like the fact that everything comes from a single manufacturer. The machine, the AutoPilot system and the customer support.

Maike Teuwsen, Site Manager

Slipform Pavers
SP 25i

Offset slipform pavers

Exhaust emission standard: EU Stage 5/US EPA Tier 4f
Max. paving width offset: 2,500 mm
Max. paving height offset: 2,000 mm

Please visit our product pages for more detailed information about our slipform pavers.

Slipform Pavers

Press/media kit

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