Exploring the recovery of fatigue damage in bituminous mixtures: the role of healing

In recent years, many studies have assessed how the healing phenomenon could recover the stiffness or the strength of bituminous materials. Nevertheless, some factors that appear during these studies have opened up a debate about whether a recovery of the damage actually occurs, and whether this recovery is lasting. This study attempts to provide an approach to these questions. For this purpose, an analysis at both micro- and macro-damage levels has been carried out, taking into account different variables. The main conclusions drawn from this study are that during rest periods without heating induction, the recovery produced in the material is mainly due to reversible phenomena. Furthermore, it has been demonstrated that although healing can recover part of the damage caused by fatigue processes it cannot restore the initial properties of the material. The restored material is still relatively brittle and due to this, the stresses generated in the zone in closer proximity to the healed cracks are higher, and the restored properties fail prematurely.