Surface Performance Characterization of Single-Layer Surface Dressing: A Macrotexture Prediction Model

Bituminous surface treatments (seal coats, chip seals, etc.) are pavement wearing courses created using asphalt binder and aggregate. They can be applied to an existing pavement or to a base course. They can act as a waterproof, skid resistant layer, sealing cracks and raveled surfaces and increasing reflection properties of road surfaces. Their expected life ranges from two to five years and are widely used in flexible pavements maintenance and rehabilitation because of reduced costs and the easiness of application. One of the most important characteristics of bituminous surface treatments is their macrotexture (initial and over time). Indeed, it affects tire-pavement interaction in wet and dry conditions and can interact with other characteristics and distress (aggregate embedment, loss of cover aggregate, streaking, bleeding, etc.). This paper focuses on the evaluation of surface performance of laboratory slabs, produced through a single-surface dressing. Macrotexture depth was measured by the Sand Patch method. A laser profilometer was also used to survey slabs texture and both aggregate descriptors and texture levels were evaluated. Finally, skid resistance and drainability data were measured by means of the British Pendulum Tester and the Belgian Permeameter, respectively. Aggregates of different size were selected in order to investigate on the relationship between aggregate dimensions and surface performance. A model was developed, implemented and validated. Results are expected to benefit both practitioners and researchers.