CONCEPTUAL DESIGNS FOR LONG LIFE, HEAVY DUTY ASPHALT PAVEMENTS

The increased demand placed on the road network, in terms of traffic intensities, vehicle axle loadings and the reduced opportunities for maintenance activities, have contributed to a greater interest in stronger, more durable pavements. It is now common on heavily trafficked routes that pavements be expected to perform for up to 40 years which, in some instances, may translate into design traffic loading in excess of 10 (super 8) ESA. As a response, the design of heavy-duty asphalt pavements has moved toward the use of flexible full-depth and composite pavements. The paper identifies a range of conceptual designs for full-depth and composite pavements subject to heavy and very heavy traffic environments. These pavements use a range of asphalt mixes placed within the pavement structure to achieve specific performance requirements. The pavements also often incorporate a cement-treated crushed rock layer to extend the fatigue life of the pavements. If the life and performance of these pavements are to be optimised then it is essential for designers to appreciate the concepts involved in their design and the influence of subsequent maintenance regimes. A discussion of the design concepts and alternative maintenance regimes are discussed in the paper. (a) For the covering entry of this conference, please see IRRD abstract no. 492019.