SUPER 1600-2 Paves Low-Noise Wearing Course
for New Bridge
Highest precision for the “Überflieger”, the high-flyer.
The transformation of parts of the Düsseldorf port into a modern office and residential area called the “MedienHafen” is aimed at attracting companies from the advertising, art and media sectors. An important element of this large-scale urban project is the new traffic concept, which also includes the construction of a bridge with an asphalt wearing course featuring optimized noise-reducing properties. On the “Überflieger” bridge, as it is known, northbound traffic turning left is routed from Völklinger Strasse into Plockstrasse without having to negotiate a crossing. The name of the bridge is derived from the elegant suspension of the road on two steel arches and routing of traffic high above the road crossing.
Special demands on the mix
The Special Construction West department of contractor Kemna Bau Andreae GmbH & Co. KG was charged with carrying out the asphalt work on the bridge. For paving the wearing course with optimized noise-reducing properties, the company used a with Extending Screed in TV version from VÖGELE. This high-precision paver is perfectly designed for the special conditions on the job site. Asphalt work on bridges is always challenging due to the confined spaces. In this case, it was even more difficult because of the different build-up of layers in comparison to standard road paving projects, as well as the special demands which asphalt with optimized noise-reducing properties makes on the paving process.
Base course of mastic asphalt
A protective layer of mastic asphalt served as a base for the low-noise pavement. This layer was a seal between the concrete structure and the wearing course. It was also necessary to profile the protective layer, as the pronounced curve of the bridge required paving with a variable crossfall. In addition, a drainage channel some 30cm wide was created on one side of the road.
Maximum evenness required
The wearing course was then paved using a material with optimized noise-reducing properties. The Extending Screed in TV version placed the wearing course without joints to a width of 5.7m and a thickness of 2.5cm. The maximum permitted variation in evenness was 4mm over a distance of 4m. This was achieved, on the one hand, by the slow pave speed of 1.1m per minute that enabled precise paving of the surfacing including connections. Secondly, only the tamper was used. Driven by an eccentric shaft, it pushes the material under the screed. On this project, a pre-compaction between 50 and 70% was achieved. The setting of the tamper was adjusted to suit the layer thickness and the pave speed. Thanks to its many years of experience and sophisticated VÖGELE machine technology, the highly qualified Kemna paving team was able to achieve a perfectly even road surface.
Easy operation proves its worth
The easy operation of the VÖGELE paver once more proved invaluable. “The ErgoPlus® operating concept is a great boon,” commented Site Manager Thorsten Schäfer. “The team members were able to concentrate fully on precise paving of the wearing course. This is especially important on a bridge, as you are working right next to the railings. In these confined conditions, the extending screed with its variable pave width was a definite advantage, as it reacts extremely quickly and precisely to changes in the pave width.”
The result: almost inaudible traffic
Asphalt with optimized noise-reducing properties, or “whispering asphalt” as it is commonly known, is gaining in popularity, especially in urban developments as in Düsseldorf, both for new construction projects and rehabilitation work. The material only absorbs the noise, however, if it is paved with great precision (see box on “Asphalt with Optimized Noise-Reducing Properties: Principle and Paving”).
Asphalt with Optimized Noise-Reducing Properties: Principle and Paving
An asphalt wearing course with optimized noise-reducing properties reduces the tyre and road noise due to its concave surface structure (plateau with valleys), its dense aggregate structure with a low fines content and a voids content of less than 6% by volume. The paving material’s high resistance to deformation ensures that the surface is durable and effective as a noise-reduction measure.
Asphalt with optimized noise-reducing properties must be paved as a thin layer with a thickness of 2 to 2.5cm. Continuous operation of the paver during paving is essential to prevent temperature fluctuations and to ensure a uniform pavement quality. The paver must also create an absolutely even surface, this being very important for reducing noise and ensuring the durability of the surface.
Source: Notes on paving asphalt wearing course with optimized noise-reducing properties for municipal road construction, Ruhr University Bochum, 2010.
Job Site Details
Paving asphalt with optimized noise-reducing properties on the “Überflieger” bridge in Düsseldorf, Germany
Length of section: 265m
Width of section: 6m
Pave width: 5.7m
Layer thickness: 2.5cm
Wearing course: asphalt with optimized noise-reducing properties
SUPER 1600-2 with AB 500 Extending Screed in TV version