Fatigue Characteristics of Bitumen-Filler Mastics and Asphalt Mixtures

Abstract

Fatigue cracking is considered to be the primary failure mechanism that occurs at ambient temperatures in an asphalt pavement. The bituminous binder plays an important role in this failure mechanism, because fatigue cracking tends to take place predominately within the binder itself. Oscillatory tests using a dynamic shear rheometer (DSR) and wheel tracking fatigue tests were carried out on a wide range of bitumen-filler mastics and on asphalt mixtures containing the corresponding mastics to investigate their fatigue relationships. The addition of the mineral filler to bitumen was found to have a significant influence on the fatigue life of mastic owing to the stiffening effect and the filler particles interrupting the crack growth in the mastic. The results of stiffening ratio showed that the 65% mastics were in the concentrated suspension region, whereas the 35% mastics were in the dilute suspension region. In terms of shear stress, the fatigue order was