A performance-based specification has been developed primarily to prevent excessive rutting occurring in the surface course and the binder course in heavily trafficked pavements under adverse trafficking conditions. This specification was developed by: assembling information to establish which layers are at risk; examining the role of the surfacing layers; investigating, in the TRL accelerated pavement test facility (PTF), the performance of rut-resistant pavement design solutions that have the potential to perform well under severe traffic loading and high pavement temperatures; comparing results from laboratory deformation tests with the performance of materials in the PTF; assessing the practicability of the specification under contractual conditions and using this experience to make appropriate amendments. The proposed new specification for the asphalt surfacing will ensure that future roads designed for heavy traffic will continue to have excellent deformation resistance even under extreme trafficking conditions. The specification will encourage better design of the asphalt surface course and the binder course and, should any problems occur in the future, it will be possible to review the performance criteria. (Author/publisher)
Abstract