Field Evaluation of Pavement Surface Treatments

The application of surface treatments (chip seals) is a highly economical highway maintenance option. Surface treatments offer protection against deterioration caused by traffic and weather. There are several material types used in surface treatments. A few years ago, the Wyoming Department of Transportation (WYDOT) initiated a comprehensive field experiment to determine the effect of materials selection on the field performance of surface treatments. Twenty-three test sections were constructed as part of this experiment. The materials used in the experiment represented the most widely used aggregates and binders in the state of Wyoming. Monitoring these sections over five years indicated that surface friction is affected by aggregate type alone while transverse cracks are predominately affected by the choice of the binder. Other interesting findings are described in the paper.