Asphalt reinforcement, Trakia Highway - Bulgaria

Situation

The Trakia Highway is one of Bulgaria’s most important transport arteries, linking the capital, Sofia, with the Black Sea coast. With up to 25,000 vehicles passing through daily, it is the country’s busiest motorway. Over the years, several sections have shown serious damage: longitudinal and transverse cracks, mesh cracks, as well as deformations and spalling have led to reduced driving comfort, rising maintenance costs and safety-related restrictions. The sections from km 10–23, km 98–119 and km 241–251 were particularly affected. To ensure the flow of traffic was disrupted as little as possible, rapid refurbishment with short closure periods was required, whilst still achieving a lasting improvement.

Solution

In order to significantly delay the formation of reflective cracks and increase the structural capacity, it was decided to use HUESKER’s HaTelit C 40/17 asphalt reinforcement, supplied by partner ViaCon. This enables a significant extension of the service life.

The asphalt reinforcement mesh, consisting of high-modulus polyester yarns and an ultra-light installation aid, is fully coated with a polymer-modified bitumen coating (bitumen content > 65%) and was applied directly to the milled asphalt base course. A cationic bitumen emulsion was used for the installation of HaTelit C 40/17 at a rate of 1.0–1.2 kg/m², resulting in optimal adhesion to the substrate. Subsequently, a 10 cm thick asphalt binder course and a 4 cm thick asphalt surface course were laid over HaTelit C 40/17. The installation of HaTelit C 40/17 was carried out simultaneously across three sections covering a total area of 946,000 m² and was achieved using specialised unrolling equipment. Adhesion tests carried out on site recorded values of up to 25 kg, demonstrating strong bonding between the asphalt reinforcement and the substrate, which ensures a very high level of process reliability and optimal integration into the asphalt structure. Thanks to its ease of handling, the asphalt reinforcement mesh could be installed quickly and efficiently, which meant that this work could be seamlessly integrated into the overall project schedule and traffic disruptions were kept to a minimum.

Advantages

The use of HaTelit C 40/17 offers a number of advantages for the Trakia Highway.

Longer service life: 
Studies show that the service life is doubled thanks to a significant reduction in reflective cracking and an increase in the structural capacity of the asphalt pavement.

Sustainability: 
The reduced need for maintenance will result in a CO2 reduction of around 221,781 tonnes over 20 years – equivalent to taking 50,000 cars off the road each year.

Cost-effectiveness: 
Extended maintenance intervals significantly reduce life-cycle costs.

Rapid construction: 
Delivery and laying of almost 1,000,000 square metres within just 41 days.

Robustness:
Over 80% residual tensile strength after installation guarantees reliable function and performance even under demanding conditions.

Practical installation: 
Direct laying on milled surfaces, high values in the adhesion tensile tests carried out and smooth asphalt paving thanks to high process reliability.