Packing theory-based framework for evaluating resilient modulus of unbound granular materials

Abstract

Enhancing the quality of granular layers is fundamental to optimise the structural performance of the pavements. The objective of this study is to investigate whether previously developed packing theory-based aggregate parameters can evaluate the resilient modulus of unbound granular materials. In this study, 19 differently graded unbound granular materials from two countries (USA and Sweden) were evaluated. This study validated both porosity of primary structure (PS) and contact points per particle (coordination number) as key parameters for evaluating the resilient modulus of unbound granular materials. This study showed that decreasing the PS porosity – higher coordination number – calculated based on the proposed gradation model, yields higher resilient modulus. Good correlation was observed between the proposed packing parameters and resilient modulus of several types of aggregates. The packing theory-based framework successfully recognised granular materials that exhibited poor performance in terms of resilient modulus.

Keywords::

• unbound materials
• packing theory
• primary structure
• porosity
• coordination number
• resilient modulus

Acknowledgements

The authors would like to extend their sincere gratitude to the Swedish Road Administration (Trafikverket) for providing the financial support for the project.