Modification of Asphalt Materials to Resist Studded-Tire Wear on Pavements

Abstract

Studded tires are used during winter seasons to reduce snow- and ice-related accidents in several cold climate regions. However, during driving the studs in these tires progressively punch into the asphalt pavement and displace small aggregates, which eventually results in pavement rutting. This article reports the results of a comprehensive testing program conducted to identify potential materials and mix design variables for the development of a wear-resistant asphalt mix to reduce the studded-tire wear associated with traffic accidents and repair/rehabilitation costs without compromising field performance. These included asphalt binder content and asphalt performance grade (PG), nominal maximum aggregate size (NMAS), aggregate type, gradation type, and addition of crumb rubber. The results show that an open-graded mix is not an appropriate alternative for studded-tire wear-resistance purposes. Slightly increasing the asphalt binder content can effectively improve the studded-tire wear resistance of asphalt mixtures with NMAS of 12.5 mm. However, this effectiveness is reduced with NMAS of 4.75 mm. Any increase in asphalt binder content to improve studded-tire wear resistance must be carefully done because it may affect permanent deformation resistance. On the contrary, crumb-rubber modification of asphalt binder is not a good option for the improvement of studded-tire wear resistance, but it can clearly improve the permanent deformation resistance as indicated by the flow number (FN) test results. Slightly increasing the fine aggregate content and changing the PG of asphalt binder can slightly improve studded-tire wear resistance, but the improvement is not statistically significant.