Effect of Temperature on Self-healing Properties of Bituminous Binders

Healing properties of bituminous binders are commonly evaluated by subjecting test specimens to oscillatory shear loading with inclusion of single or multiple rest periods. In almost all protocols adopted by researchers, during both loading and rest phases the same constant temperature is imposed to the specimen. However, it is widely recognized that temperature may have a great impact on healing mechanisms taking place in the binder. In order to address this issue, this paper investigates the healing properties of bituminous binders by means of a test procedure which consists of two time sweep tests conducted at the same temperature and by an intermediate rest period whose temperature is set at different values. Response of the material is quantitively assessed by introducing two healing indicators based on stiffness and strength recovery, respectively. Discussion of the experimental results presented in this paper underlines the relevance of temperature which needs to be taken into account to correctly rank bituminous binders in terms of their self-healing potential.