An Unusual Experiment with Asphalt Has Started Near Riga: What Will Change on the Roads? 0 72

On a section of the Vidzeme Highway (A2) in the Ropaži municipality at the border of Riga (12.88–13.48 km), an experimental asphalt surface has been laid as part of a research project, where part of the traditional bitumen has been replaced with biologically derived additives. The project is being implemented by Vianova with the support of the State Joint Stock Company Latvijas Valsts ceļi (LVC).

As project participants explain, laboratory tests are not sufficient — to assess the real properties of the new surface, it needs to be tested under conditions of intensive traffic.

The project "Development of Sustainable Asphalt Mixtures with Reduced Carbon Footprint" aims to create a road surface that will reduce CO₂ emissions during production while maintaining operational characteristics at the level of traditional asphalt. A total of six different types of warm asphalt mixtures are planned to be developed and tested.

Rolands Izaks, head of the production department at Vianova, noted that the experimental section is the result of international cooperation, bringing together the expertise of Latvian and foreign specialists.

According to him, laboratory tests have shown that the new mixtures with reduced CO₂ emissions have characteristics comparable to traditional ones. Now it remains to check how durable they will be under real operating conditions.

Janis Baumanis, project manager at the Research and Development Department of the Road Competence Center LVC, emphasized that the project will allow for the simultaneous testing of several asphalt production technologies that potentially reduce energy resource consumption and harmful emissions.

He noted that the selected section is ideal for testing due to its technical condition and very high traffic load. In just a few years, specialists will be able to compare how the experimental surfaces age compared to traditional ones.

The selected section of the road has long needed repairs: transverse and longitudinal cracks, a cracking network, and local destructions have appeared on the surface. Moreover, this is one of the busiest road sections in Latvia. In 2025, the average daily traffic intensity here exceeded 40,000 vehicles, with approximately one in eight vehicles being a truck.

On the 600-meter section, the old surface was removed to a depth of 10 centimeters, after which a six-centimeter binder layer and a four-centimeter top layer were laid. The experimental surface has been laid only in the right lane, which carries the majority of freight traffic.

A total of six different types of asphalt mixtures are used, differing in the content of bitumen, bio-bonding components, and recycled asphalt.

The contractor provides the same warranty for the experimental surface as for regular road works — three years. The project is being implemented without attracting funds from the state budget.

This is not the first such experiment. In 2024, asphalt in which part of the bitumen was replaced with lignin was tested on a neighboring section of the Vidzeme Highway. So far, specialists have not identified defects related to the use of this additive or recycled asphalt. However, LVC emphasizes that the main question is the durability of the surface. That is why monitoring of the experimental sections will continue for several years, as significant differences compared to regular asphalt may only become apparent over time.

If the tests confirm the reliability of the new materials, Latvia will be able to use more environmentally friendly road construction technologies that reduce carbon dioxide emissions without compromising the quality of the roads.