When construction company Matthäi was hired to complete the resurfacing of the busy B420 road around Fürfeld in Rhineland-Palatinate, Germany, it needed to navigate tight deadlines and tricky working conditions.

One of the biggest obstacles Matthäi faced with this project was avoiding heavy traffic jams caused by road closures. Because of this, the decision was made early  to work only on weekends. To meet these tight deadlines, teams had to work across three weekends, resurfacing a one-kilometer section each time. Over the course of the project, around 40,000 square meters of asphalt surfacing and binder were needed, along with 9,000 tons of material being milled, shifted and laid again.

Turning weeks into days

Traditionally, the surveying process for resurfacing a road is a time-consuming task that can lead to expensive errors. Surveyors hammer pegs into the ground every five meters along the hard shoulder, then they need to measure the transverse profile every 20 meters, evaluating all the photos, drawing up marking schedules, and ensuring all the relevant data is documented. Using the Topcon SmoothRide solution, Matthäi was able to optimize the recording and use of data during the project, to ensure the work was completed quickly and without complications.

The Topcon team utilized a RD-M1 scanner on the roof of a car and drove down the entire stretch of road in less than an hour. They were able to record millions of points in this way in just 50 minutes.

“On the basis of a thinned-out point interval of 30 centimeters, we received a complete image of the road,” said Frank Pohl, Matthäi surveying team leader. “We then discussed the critical zones and found solutions to various problems quickly. The team was able to smooth out uneven spots in the planning model that could have caused further problems and optimized the geometry in such a way that the incline of the new asphalt surface was a constant 1.5 percent—leading to a perfect end result.

The curves on the road were also given equally smooth gradients, and this traditionally time-consuming planning phase was completed in just two days.”

Results through data

The next step in the process was to send the completed model to the milling machinery. SmoothRide uses GNSS for positioning, which allows users to mill only what is necessary, down to the exact millimeter, by milling the differences between the existing surface and the new design.

The pre-fitted milling machines were equipped with the 3D components, and this took just 20 minutes to implement as Raimo Vollstädt, support engineer at Topcon, explained.

“With SmoothRide’s components, everything is automated, allowing the milling machine to know its position on the road at all times,” Vollstädt said. “This saves a lot of time and means that the machine never has to be adjusted, which is especially beneficial when milling in the dark. What’s more, multiple machines can be set to run simultaneously, which makes the process all the more efficient and is crucial when working to tight deadlines.”

The milling machines were set off to mill along the six-meter-wide and one-kilometer-long section of road four times during the night, in line with the planned design. Sixteen trucks were on site to transport the asphalt millings to the mixing plant where they were processed for reincorporation into the binder. The team needed to have all milling works up to the slip road into Fürfeld completed before the road reopened, and due to the efficient process, they achieved this one hour ahead of schedule.

Thanks to this efficient and accurate milling process, the asphalt could then be laid ensuring consistent thickness. The paver was able to lay the binding layer evenly to a thickness of five centimeters, and the surface could be laid the same day.

This technology meant that residents did not have long to wait to have full access to the road again, even in the interim weeks between road closures, helping to ease disruption to local life. Overall, the process was efficient and resulted in the road closure being lifted earlier than expected.

Klaus Kormann, site manager for GMS, the milling company, was impressed with the outcome. “Thanks to SmoothRide, every part of the process ran smoothly, without any complications, and the technology delivered exactly what it promised…With the process now completed, this stretch of the B420 has a new lease of life, making it a much better driving experience for all road users.”