Abstract
The resilient behaviour of an unsaturated, unbound granular material is a primary input used in the mechanistic analysis of pavements incorporating such layers. Various models exist for the determination of the resilient behaviour, mainly based on the output of tri-axial laboratory testing. This paper describes an investigation where basic engineering properties such as grading, laboratory compaction characteristics and optimum moisture content are incorporated into the resilient behaviour model to quantify the effect of basic material properties on the resilient response of unsaturated, unbound granular materials. Such a resilient behaviour model will enable practitioners to estimate the behaviour of specific material, which might enable the use of available quality material that was discarded in the past. Data from tri-axial laboratory tests on materials originating from the Long Term Pavement Performance test sections are combined with basic engineering parameters of typical unbound granular material through a statistical modelling process to develop a model for predicting resilient behaviour, which can be used as a practical predictor of the expected behaviour during a Level 2 and/or Level 3 Mechanistic Empirical Pavement Design analysis. The work illustrates the process and the potential to develop a general resilient behaviour model for unbound granular materials incorporating saturation effects.
Shakedown of unbound granular material