Self Healing Asphalt - Extending the service life by induction heating of asphalt

Extending the service life of an asphalt surface layer is always a continuing desire. This can be done by improving the quality of the product when laying. Another possibility is to upgrade the quality throughout the service life. This is the method to Self Healing Asphalt. The aging of asphalt under weather and traffic is associated with the formation of micro cracks in the mortar fraction. By adding a conductive material in the asphalt production, such as steel wool fibres, the possibility arises of heating up the mortar of the asphalt by an induction device. A short "heat shot" through the steel fibres, causes melting of the bituminous binder and because of that, hairline cracks in the asphalt layer are closed. The asphalt mixture will "reset" and start a new life. This can be done several times during the service life. In The Netherlands from 2010 several tracks have been laid with Self Healing Asphalt. In 2014 also the first healing action on site was carried out. The results are promising. This development for instance opens new ways to a broader application of noise-reducing road surfaces. These surfaces are susceptible to damage from twisting movement of traffic and therefore cannot be applied to many projects. By providing the most critical locations with Self Healing Asphalt the quality during the life can be maintained by periodic induction action. Also, making noisy expansion joints noiseless, this material can play an important role. In the paper the principle of Self Healing as well as several applications will be reported.