Fundamental characterisation of reclaimed asphalts: the importance of testing homogeneous specimens

This study highlights the importance of defining appropriate specimen manufacturing procedures when assessing the fundamental properties of reclaimed asphalt (RA) mixes for further modelling purposes. Two gyratory compactor procedures were used: the first leading to specimens with a non-uniform air voids distribution and the second tailored to obtain homogeneous specimens. The study was performed by using three stone mastic asphalts incorporating up to 30% of RA but designed to have identical properties. A detailed characterisation of the loose mixes and binders, an X-ray computer tomography micro-structural study of the manufactured specimens and a further mechanical characterisation showed that testing non-homogeneous gyratory specimens leads to a significant overestimation of the mechanical properties of asphalt mixes. This study has been developed within the FP7 project ReRoad.