Design of long life flexible composite and deep strength asphalt pavements

Long life asphalt pavements are designed to provide strong, durable pavement structures having a structural life exceeding 50 years with only periodic removal and replacement of the asphalt surfacing layer required during this period. This paper presents the authorrs design model for long life, flexible composite and deep strength asphalt pavements (PLLP) which will produce structurally strength balanced, cost-effective, long life asphalt pavements. The PLLP long life asphalt pavement design model presented in this paper is based on the fatigue endurance limit for cemented layers as proposed by the author and defined in this paper. The determination of the fatigue endurance limit is based on the extensive published pavement research work carried out by various eminent researchers and research organizations around the world to investigate the performance of cemented layers in pavements. PLLP long life asphalt pavements consist of an upper asphalt layer supported by lean concrete and cemented subbase layers overlying the pavement foundation layers. The lean concrete and cemented subbase layers are designed to always remain below the threshold fatigue strain limit of the layers. This allows these layers to remain in their initial intact state at construction throughout their entire life and enable the pavement to carry unlimited traffic loading. The design approach for long life asphalt pavements presented in this paper may be used for the design of heavy duty pavements for motorways, ports, container terminals, heavy industrial areas and airports.