Permanent deformation prediction modelling of asphalt concrete layers based on Accelerated Pavement Testing

Resumé

One of the main distresses that Mechanistic – Empirical (M-E) design methods
attempt to control is permanent deformation (rutting). The objective of this paper is to
evaluate an M-E permanent deformation model for an asphalt layers using test results from
accelerated pavement testing. Two series of Heavy Vehicle Simulator (HVS) test structures
were used. The permanent deformation, wheel loading, pavement temperature, and other
material properties were continuously controlled during the HVS testing. The performance
measurements were made at 10, 20 and 30°C pavement temperatures. Asphalt concrete layers
were considered as linear elastic and their stiffness was modified according to the loading
temperature where as stress dependent behaviour of unbound materials was considered when
computing input parameters (stress and strains) for the M-E permanent deformation model.
The traffic wandering was also accounted in modelling the traffic assuming normal wander
distribution and a time hardening approach was applied to accumulate the permanent
deformation contributions from different stress levels. The measured and predicted permanent
deformations are in general in good agreements for 10 and 20°C temperatures however for a
temperature of 30°C, the M-E model over-predicted the permanent deformations behaviour
thus a better characterization of material properties and more validation is needed.