Fatigue, self-healing and thixotropy of bituminous mastics including aged modified bitumens and different filler contents

Bituminous mastic is a self-healing viscoelastic material. Recoverable phenomena, such as thixotropy and self-healing capability, are recognised as an important resource for the development of sound road pavements. The experimental investigation described in this paper and carried out through a Dynamic Shear Rheometer (DSR) provides a comparison among mastics blended with different percentages of aged polymer modified bitumen, new virgin polymer modified bitumen and filler in terms of fatigue, self-healing and thixotropy. Data analysis is based on a model adopted in previous studies for polymer modified bitumens in order to calculate the fatigue endurance limit. Results show that the presence of increasing percentages of filler causes detrimental effects on mastic fatigue performance which can be offset by the addition of a certain amount of aged polymer modified bitumen. In fact, regardless of the filler content considered, a percentage of aged polymer modified bitumen (up to 45%) added to mastics enhances the fatigue endurance limit suggesting significant benefits when dealing with sustainable recycled mixtures containing Reclaimed Asphalt (RA) aggregates.