Experts warn that such “durability” is not something to be proud of: initial damages that are not repaired in time penetrate deeper, so instead of relatively minor surface repairs, the entire road structure may need to be fixed later. However, new technologies already allow problems to be detected before potholes appear, and old asphalt, tires, and even materials left after waste incineration can be used in road construction anew.
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According to Šarūnas Frolenko, head of the “Lithuanian Roads” association, road durability depends not only on the investments allocated. It is increasingly important how much of the existing materials can be reused, how the quality of work is controlled, and whether the first surface damages are detected early enough.
“In modern road engineering, we must evaluate the entire life cycle of the road. A durable road is not one that we leave untouched for as long as possible. On the contrary, timely decisions help avoid situations where a small problem grows into a repair of the entire structure,” says Š. Frolenko.
Good materials alone are not enough
According to Dr. Ovidijus Šernas, director of the VILNIUS TECH Road Research Institute, there is no single technology or material that by itself guarantees road quality. The result depends on the whole chain – how the road is designed, how the work is done, and how it is maintained afterwards.
“It is possible to use very high-quality materials, but if traffic loads, soil conditions, water drainage, or road structure are improperly assessed, this can significantly shorten the pavement’s service life,” says O. Šernas, who has been researching road materials and the use of recycled raw materials in asphalt mixtures for over a decade.
One of the solutions already applied in Lithuania is cold road surface regeneration, where part of the existing structure is reused. During repair, it is crushed, mixed with reinforcing materials, and returned to the road base. This reduces the need for new raw materials.
Not only old asphalt can be reused – slag formed after municipal waste incineration has already been tested in road structures in Lithuania. Additionally, VILNIUS TECH scientists have studied the use of recycled car tire rubber in asphalt mixtures.
According to O. Šernas, in such cases, the most important thing is not that the material has been used before, but whether its properties are suitable for the specific purpose.
“Properly prepared and tested secondary raw material can be a full-fledged engineering material. The key question is not whether it is recycled, but what its properties are and what function it will perform in the mixture or road structure,” says O. Šernas.
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According to O. Šernas, studies have shown that recycled tire rubber can also improve the properties of the asphalt itself. Adding up to 1.5% rubber to the mixture made the asphalt more resistant to rutting and frost-induced cracks. However, the final result also depends on the amount and type of rubber chosen.
“This once again confirms that the principle ‘the more, the better’ does not apply here – each mixture must be properly designed and tested,” says O. Šernas.
The road can be inspected before potholes appear
After newly laying a road surface, it is important to assess whether the work meets the specified requirements and whether there are defects that could later cause faster wear. According to Š. Frolenko, head of the “Lithuanian Roads” association, methods are already being tested in Lithuania that allow for more detailed surface inspection and earlier detection of possible defects.
Last year, a ground-penetrating radar was tested on the Vilnius–Utena highway for this purpose. Usually, the quality of newly laid asphalt is checked by drilling samples – cores. They accurately show the condition of a specific spot but provide information only about selected points. The ground-penetrating radar allows checking the entire examined section without damaging the surface and identifying places where more detailed investigations should be carried out.
“The road begins to age long before the driver sees the first pothole. If we can see not just a few randomly selected points but practically the entire laid section, the principle of quality control changes. The goal should not be to find an already existing defect but to prevent it from forming,” says Š. Frolenko.
Another technology increasingly used in Europe is reduced-temperature asphalt mixtures. They are produced and laid at lower temperatures than conventional hot asphalt, thus requiring less energy for production and reducing emissions. New methodological guidelines are being prepared in Lithuania this year, which should facilitate wider application of this technology.
However, according to Š. Frolenko, the most important condition is to detect changes in road condition in time and respond to them.
“A durable road is not one that we leave untouched for forty years. A durable road is one whose structure we manage to preserve by timely performing smaller interventions. If we wait until the damage reaches the base, we repair not just the surface but the entire road. Therefore, sometimes the greatest innovation is not a new material but the ability to know precisely what, where, and when needs to be repaired,” says Š. Frolenko, head of the “Lithuanian Roads” association.
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