As a viscoelastic material, the stiffness and structural performance of asphalt is highly dependent on temperature when subject to wheel loading. Typical methods adopted in determining an asphalt design temperature for flexible pavement design include the Weighted Annual Mean Pavement Temperature (WMAPT). The WMAPT procedure is one that has been determined to estimate the pavement temperature to a depth of 100mm (Shell, 1978) using Weighted Mean Annual Air Temperatures (WMAAT) and does not account for contributing factors including asphalt thickness greater than 100mm and variations to mix composition. To develop a greater understanding of the thermal performance of full depth, deep strength and Long Life Asphalt Pavements (LLAP) a calorimeter was designed to identify asphalt mix thermal properties including albedo, emissivity, thermal conductivity and to replicate insitu temperature seasonal variation located at the University of the Sunshine Coast. The calorimeter based procedure produced data to represent a thermal gradient for two mixes including Recycled Asphalt Product (RAP) and glass based asphalt samples up to a depth of 450mm and developed trends for insitu transient seasonal temperature variation including upper and lower bound limits for the seasons of Winter, Summer and Spring. Modelling was undertaken for a variety of pavement thicknesses for the purpose of comparing the three-season design temperature method to that typically adopted by the WMAPT. A reduction in pavement thickness was identified to be in the order of 10 -15% and outlines significant cost saving benefits into the conventional mechanistic pavement design approach.
16th Australian Asphalt Pavement Association (AAPA) International Flexible Pavements Conference: Innovation Driving Value, Gold Coast, Australia 13-16 September 2015