Fatigue comparisons of mortars at different volume concentration of aggregate particles

Fatigue cracking is one of the primary failure mechanisms in asphalt pavements and it predominantly occurs within the mortar phase. For this reason, in recent years, a number of studies were carried out by various researchers to better understand the fatigue mechanism in such a critical mixture phase. In the present work, time sweep tests were performed in strain control mode on asphalt mortars prepared with three volume percentages of fine aggregate at different aging conditions. In particular, two different asphalt mortars were used: one containing Recycled Asphalt Pavement (RAP) materials and the other one composed of the same RAP aggregate skeleton without the aged binder. The influence of the different aging conditions, the presence of the aged binder and the addition of fine aggregate particles on the fatigue resistance of the mortars were evaluated. Moreover, a relationship between the parameters of the obtained fatigue laws and the different aging and mix design conditions was found. The proposed relationship can be easily used to predict the fatigue resistance of a mortar composed of a specific volume concentration of aggregate particles and recycled material. The potential extension of the proposed relationship to mixtures may eventually result in the implementation of a simple analysis tool for practitioner limiting the need for more sophisticated and expensive fatigue tests on asphalt mixtures.