Evaluation of self healing properties of bituminous binders taking into account steric hardening effects

Steric hardening is a time-dependent phenomenon that can affect the healing properties of bituminous binders. In the experimental investigation reported in this paper, the rheological test method proposed for the evaluation of healing involved the use of a prolonged rest period included between two continuous oscillatory loading phases. A simple model was developed to subtract the contribution of steric hardening to the total stiffness gain attained during rest and thus to evaluate the recovery in mechanical properties due to self healing only. Analysis of the results indicated that cumulated damage of binders is composed by a reversible and a non reversible part. True self healing potential of the materials, as evaluated by means of the relative reversible damage index (RRD) and the relative index of fatigue life increase (RFIHEALING), was found to be a function of imposed damage, binder source and polymer modification.