Senior lecturer, School of Civil Engineering, University of New South Wales, Kensington, NSW
Senior scientific officer, Parramatta Division, Department of Main Roads, New South Wales, Parramatta, NSW
Pages: 9 Published: Jan 1989
Increasing rutting and cracking life is a financially rewarding exercise for the road authority. It appears that pavement life can be increased by paying particular attention to the plastic, as well as the elastic, behavior of asphalt concrete mixes and to their relationships with the base and subgrade of the road. The authors have selected Section 2 from the Department of Main Roads, New South Wales Rooty Hill Field Trial site near Sydney to demonstrate theoretically how both rutting and fatigue cracking life can be greatly extended by adjusting the elastic and plastic properties of the 200-mm-thick asphalt concrete pavement. Instead of formulating different mixes, the properties were varied by altering, in simulation, the temperature of the asphalt concrete. It was found that, for this particular pavement design, maximum rutting and cracking life can be achieved by grading the asphalt concrete properties from stiff nonplastic at the surface down to soft elasto-plastic at the bottom of the asphalt concrete. By contrast, the reverse grading allowed only 12 000 standard axle passes before fatigue failure. When representative field conditions were simulated, the mechano-lattice theoretical predictions were borne out by measurement.
Permanent deformation, fatigue cracking, pavement life, elasto-plastic surface, rutting, mechano-lattice analysis, computer simulation, stresses, asphalt concrete, mix design, asphalt specifications
Paper ID: STP20071S