A macro geomechanical approach to rank non-standard unbound granular materials for pavements

The results of an experimental work on three non standard road granular materials and a standard one are presented, including small strain precision triaxial tests under cyclic loading. The non standard materials have index parameters such as attrition coefficient, plasticity index, and fines content above the allowed limits of road specifications. The role of each parameter and the influence of the water content on the macro mechanical behaviour are studied. The geomechanical behaviour is evaluated by coupling resilient modulus and resistance to permanent strains. Results show an almost unique relationship between these parameters for each geological origin of the studied materials.

Research highlights
► New ranking of unbound road granular materials based on mechanistic approach.
► Highlighting the importance of drainage when using non standard materials.
► Highlighting relation between mechanical properties of road materials and geology.
► Enhancing suction to characterize the sensitivity of materials to hydric changes.
► Relating water sensitivity to geological history.