Proper maintenance
Winter service
When clearing snow, care must be taken not to damage the surface layers. For example, snow plows should be operated with great caution. Preventively, especially with SDA surfaces that have a high void content, preventive salting using a sole can prevent the later necessity for more aggressive clearing methods. Prevention is emphasized, for example, in the canton of Zurich, where no special maintenance or winter service takes place yet, but where operations tend to be initiated earlier to clear the surfaces gently. In the canton of Aargau, there are also no specific requirements or regulations for winter service or the handling of accidents or contamination with oil on SDA surfaces. In the canton of Fribourg, the routes with SDA are marked with signs to indicate the requirement for a gentle winter service.
Structural renovation measures
According to the standards of the Swiss Association of Road and Traffic Professionals (VSS), the structural measures for SDA surfaces (sound-absorbing asphalt surface layers) do not fundamentally differ from those for conventional surfaces. Minor structural measures are understood, according to VSS 40 731, as repairs in the sense of immediate measures aimed at limiting damage and ensuring traffic safety. This includes particularly the filling of potholes, sealing of cracks, and rectifying local deformations. Larger interventions aimed at preserving the substance or restoring the desired condition are referred to as restorations (VSS 40 731). Furthermore, reinforcement measures according to VSS 40 733 may be necessary if the load-bearing capacity of the surface can no longer be guaranteed in the long term.
In comparison to dense asphalt surfaces, SDA surfaces exhibit better grip durability over their service life due to the high requirements for the polishing resistance of the used aggregates (PSV value) (VSS 40 525, VSS 2019f).
When rolling over, for example, curbs or other surface layers, distinctly audible noises can occur, which may be disturbing for residents—especially when the surrounding road surface is very quiet.
According to the information sheet Kt AG IMS 404.950, structural renovation measures are carried out in two stages for areas of about 6 m² or more. From this size, the use of SDA or LA/MA mixtures is required. In practice, however, controlling the correct application is difficult.
In other cantons, for example, it is stipulated that machine patching must be reinstalled over a length of at least 20 m.
For small-area damages (< 5 m²), conventional asphalt mixtures or LA/MA mixtures are usually used, as the use of SDA mixtures is not economically or technically sensible for small areas. Only for larger repairs (> 5 m²) is SDA mixture used. In principle, there are no significant differences between maintenance work on SDA surfaces and that on conventional surfaces; cracks are also sealed and spalls are patched on SDA surfaces.