The new 2002 AASHTO Guide for Pavement Design advocates the use of the resilient modulus parameter for the characterization of granular materials used as base and sub-base layers in flexible pavements. The multitude of factors that affects the resilient behaviour of granular material makes the determination of the resilient modulus at different loading and physical conditions a critical factor for the pavement design process. This calibration task requires the availability of a robust system capable of producing the needed results in a timely and effective fashion. The current paper reports on recent research activities at the National Research Council, which aim at providing tools that can be utilised to carry out the calibration process. The objective of the research program is to establish database of resilient moduli for the different types of granular materials used in the Canadian Provinces. The research program combines both laboratory testing and numerical techniques to develop the required database. The paper presents an overview of the characterization system together with typical results obtained. Application of the new system to quantify the effect of compaction density, a major construction factor affecting the behaviour of granular material, on the resilient modulus is illustrated. Preliminary results obtained from repeated load tests and discrete element modeling (DEM) confirm the adequacy of the developed tools to produce the sought database
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