How wear affects road surface texture and its impact on tire/road noise

Abstract

Mechanical pavement wear in the Nordic countries is essentially influenced by the use of studded tires during long winter seasons. The abrasive effect of the studded tires is the cause of significant damage on the pavement and a contributor to rutting. In addition, the mechanical aggregate removal due to the studded tires is the reason for significant changes in the road surface texture. At traditional dense asphalt pavements, the mechanical wear is initiated by the abrasion of the mortar, which leads to a protrusion of coarse aggregates. Regarding the noise characteristics of asphalt pavements, those texture alterations will have a negative impact. Several methods to reduce the noise emission have been investigated. However, in the Nordic countries, the reduction of maximum aggregate size in the mix design of asphalt pavements is considered the most efficient way to develop satisfactory pavement noise characteristics. The challenge is to find the right balance between the wear of the mortar and the wear of the coarse aggregates to produce a limited worn surface with positive acoustical characteristics. Within this study, common Norwegian asphalt mixture types, including different rock materials and binder types were investigated to study the effect on pavement wear, the resulting changes in surface texture and the road's noise properties. Laboratory tests were carried out to simulate the wear by studded tires. The texture characteristics were measured on the test specimens, both initially, during and after testing. In addition, pavement wear, surface texture and tire/road noise was measured on several full-scale test sections. A reduction of the maximum aggregate size causes an increase in mechanical wear by studded tires. However, by reducing the maximum aggregate size, both the initial surface texture and the surface texture of the worn pavement have a positive effect on the acoustical characteristics of the asphalt pavement. The characteristics of the rock material used for the aggregates in the asphalt mixture is crucial for the pavement service life and the development of the surface texture. By using a rock material in the fine fraction that is more resistant against the wear by studded tires than the rock material used for the aggregates in the course fraction, the wear of the pavement surface will be balanced and result in a surface texture that is favorable for little noise generation. To reduce the wear and keep positive acoustical characteristics, a gap graded asphalt mixture type is preferable.