Road surface repair – S37 Klagenfurt Expressway

Situation

The Klagenfurt Expressway S37 (originally Federal Road B 317) in Austria connects the Carinthian capital Klagenfurt with the town of St. Veit an der Glan in the north. In its final phase, the S37 is to be extended to Scheifling in Styria, thereby providing an alternative route to the A2 South Motorway for the Vienna–Klagenfurt section, in conjunction with the S36 Murtal Expressway and the S6 Semmering Expressway. The increasing traffic volume in the past – the introduction of the lorry toll in Austria in 2004 led to a significant increase in lorry traffic avoiding the toll on this section of road – resulted in very high stress on the asphalt layer, causing cracks to form on the road surface.
Extensive rehabilitation measures were required to maintain the serviceability and road safety of this important transport route. These measures were to be designed to rehabilitate the affected sections as cost-effectively as possible. Furthermore, it was to be ensured that the formation of new cracks is prevented or delayed in the long term!

Solution

Based on decades of positive experience using  HaTelit asphalt reinforcement in numerous projects, which have demonstrably confirmed the prevention or delay of reflective cracking, it was decided to use HaTelit for the rehabilitation of the S37. 
Following the positive results achieved during the rehabilitation of a section in spring 2015, it was decided to use the HaTelit asphalt reinforcement mesh for the main rehabilitation works in summer 2018 as well. For the rehabilitation, 4 cm of the existing asphalt structure was first milled off and then cleaned using high-pressure water jetting (HPWJ). The HaTelit asphalt reinforcement was laid on the dried milled surface, which had been pre-treated with a polymer-modified bitumen emulsion (70% bitumen content), in accordance with the installation instructions provided by the manufacturer, HUESKER Synthetic GmbH. To ensure simple and secure installation, the HaTelit asphalt reinforcement is equipped with an ultra-light non-woven fabric, which is additionally coated with a polymer-modified bitumen coating (bitumen content > 60%) to achieve optimal bond between the layers. Following the installation of the HaTelit asphalt reinforcement, the surface course (SMA 11) was laid to a thickness of approx. 4 cm.

Advantages

The positive practical experience gained over decades of use in numerous national and international projects, documented by scientific studies, shows that the service life of road surfaces is significantly increased by the installation of HaTelit and that maintenance intervals can be significantly extended. For road maintenance authorities, this means that the slightly higher investment costs (asphalt reinforcement, binder + installation) for the rehabilitation works are recouped in the short term and maintenance costs are significantly reduced due to the extended service life.