Thin Sealed Flexible Pavement Design For Gold Coast Sands

Pavement design to the method set out in the Austroads Pavement Design Manual (APDM) is performed as a function of the elastic properties of the subgrade material. Due to the relative uniformity in composition of the aeolian and alluvial sands in the Gold Coast region, the elastic properties of these materials need to be investigated. In this paper, the physical properties of representative samples of these soils from differing regions within this area are established to allow identification of materials. A modification of the Australian Standard Test Method AS1289.6.1.1 “Determination of the Californian Bearing Ratio of a Soil” is used to correlate density index to CBR and the Resilient Modulus of these samples are established from Repeated Load Triaxial Test (RLTT) results. Pavement designs are then compared by the empirical and mechanistic procedures for unbound flexible pavements with thin asphaltic seals. The results of the analyses are presented in graphical form as well as recommendations for correction values to align the two design methods.