Asphalt roads require regular maintenance or replacement. For instance, the normal lifespan of a noise-reducing topcoat is around 8 years. This leads to high costs and is a nuisance for vehicles. However, improvements can be made if asphalt layers last longer, without deterioration, on the road surface. This is possible with the self-healing asphalt developed by Heijmans, Intron and TU Delft.

Heating via induction

Due to the used materials, self-healing asphalt is able to repair minor damage all by itself. Metal fibers in (conventional) asphalt blends allow hairline cracks in the surface to be filled automatically. The process works as follows: heat is generated in these fibers when an induction device is driven over the surface. This then causes the surrounding bitumen to melt temporarily. The approach thus allows old layers of asphalt to be 'renewed'. Hairline cracks are sealed and the potential loss of adhesion with minerals in the asphalt is repaired. This can help to significantly extend the lifespan, particularly regarding silent road surfaces that are highly susceptible to aging.

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The treatment causes few problems and can be repeated several times. If repeated three times, the lifespan can be extended by 50% to 100% compared to normal silent road surfaces. And this results in a CO2 reduction of 40%.

In practice

In the Netherlands the A58 highway features a test section of self-healing asphalt that measures several hundred meters. At the end of June 2014, Heijmans successfully carried out its first induction treatment. This innovative pilot was carried out under assignment from the Dutch Ministry of Infrastructure and the Environment. Since then, self-healing road surfaces have already been laid, by Heijmans in various locations in the Netherlands.

Self-healing asphalt offers a solution for road owners who are looking for lower maintenance cycles and fewer traffic delays due to road works. The material is especially useful in areas with very high traffic loads and on locations where tear of road surfaces is more intense, like intersections and tight curves.

Self-healing asphalt is an extremely cost-effective way to lower maintenance cycles.

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