Thin Surface Course Systems (TSCS) are now the primary surfacing material used on the Highways Agency’s strategic road network. TSCS use more high specification aggregate (aggregate with high resistance to polishing) than older surfacing types such as hot rolled asphalt because it is incorporated throughout the surface course rather than being spread on top. The work described in this report investigates two potential methods for more sustainable use of virgin aggregate resources. Two laboratory experiments were carried out, examining the effect on friction of combining high specification virgin aggregate with either lower-specification virgin aggregate, which is more abundant, or with reclaimed asphalt, use of which in the surface course is currently restricted.

Want to know more about this project?