Road to better asphalt

A Delft University researcher has developed a model of the damaging influence of water and traffic on asphalt, which could help save time and money lost on repairing damage caused by water infiltration.

In the Netherlands, extremely open asphalt concrete (ZOAB) is used, which is more prone than most to water damage. ZOAB has to be repaired once every six to nine years. According to Delft PhD candidate Niki Kringos it is better to prevent asphalt damage than to simply keep repairing it.

Asphalt suffers damage through the combination of penetrating water and ongoing stresses caused by moving vehicles. Damage to the road surfaces can reveal the negative effect that water has on the material properties of the asphalt components and their binding.

Kringos succeeded in using her own computer program to model the deterioration in asphalt arising from the combined action of water infiltration and mechanical load. The simulations showed that relevant variables included the maximum moisture retentiveness, the moisture diffusion and the binding strength of the various asphalt components. Differences in these appear to have the greatest influence on the degree of asphalt damage.

Kringos’ program could contribute to developing an improved and structured material selection which may lead to asphalt types which can last longer.