The coastal town of Norddeich on the East Frisian coast in Germany is a popular destination for tourists who enjoy the view of the Wadden Sea from the dyke. However, for the locals, the dyke plays a vital role in coastal protection. This protection includes a revetment, partially made of asphalt, which is now being renewed by the Tell Bau GmbH using ASW Asphalt Profi-Thermo.

A sunny September morning shortly after 9 o’clock: The mudflat is barely covered by a thin film of water at low tide, and the blue sky reflects in it. Wooden stakes and pruned bushes are exposed, while at the base of the dyke, the protective asphalt revetment begins. Although it may look like a road at first glance, it is usually not traversed and serves only as protection against the sea.

Kilian Efen, the site manager of Tell Bau GmbH, drives along the sloping side of the dyke in his car. These rides are part of his professional duties, as his company is renewing the asphalt revetment. This process is referred to in professional terms as “revetment enhancement.” He explains that driving on this sloping surface takes some getting used to, even after an extended period. The inclination of the dyke, at times 23°, is demanding and requires special attention both in driving vehicles and operating the asphalt paver.

The slope not only poses a challenge for transporting vehicles to the construction site but also for asphalt installation. Special precautions are necessary to prevent the asphalt mix from overflowing. Special thermally insulated tipping bodies with push-off technology from Fliegl – called ASW Asphalt Profi-Thermo – are used to deliver the asphalt mix because conventional tipper trucks would overturn due to the slope. This technology ensures that the asphalt mix falls layer by layer into the paver, achieving a more uniform mix temperature. “With a normal tipper, the center of gravity would be too high. It would tip over on the slope here,” explains Kilian Efen. Tell Bau also employs the push-off technology on flat construction sites. “The asphalt mix falls layer by layer into the paver. This way, we have no segregation and a more uniform mix temperature,” says Efen. “It may not weigh heavily in warm weather like today, but it can get quite cold and windy here in the north.”

The revetment protects against waves and holds particular significance in this coastal area. Dr. Thomas Schoneboom, Head of planning and construction at the Aurich branch of the NLWKN, explains that dykes with a foreland are less affected by waves. However, the so-called Schardeich in Norddeich lacks a foreland, causing waves to impact the dyke more. The revetment provides protection against this. Due to cracks and weaknesses in the existing asphalt revetment discovered during inspections, it had to be renewed. To meet the requirements for surface weight, more asphalt was added than removed. This recycled asphalt is mostly reused.

The construction team on the site works efficiently, applying around 1500 tons of new asphalt to the revetment daily. Working on this dyke construction site not only offers a sea view but also a calm and pleasant working environment. The renewed asphalt revetment will contribute to ensuring the dyke’s protective function in Norddeich for the next decades.