The Effect of Aging on the Rheology and Fatigue Response of Bitumen in Relation to Raveling in Porous Asphalt

Resumé

Due to ever increasing traffic loading, the need for long lasting pavements is growing. At the same time the demand for quieter roads is also becoming crucial in the Netherlands with its dense population. Porous asphalt (PA) is extensively used as surface layer on motorways in order to reduce traffic induced noise. However, the durability of PA layers is relatively low because of the high voids content in the mix. In this study, the effect of aging on the binder performance was investigated. The rheological investigation revealed that increase in modulus is achieved in the high (low frequency) and intermediate temperatures while no significant change is achieved at low temperatures. The fatigue response of the binder to repeated application of shear loading at intermediate temperatures using the time-sweep test in Dynamic Shear Rheometer (DSR) showed higher rate of damage development in aged binders but the performance was better than the unaged bitumen according to the evaluation made using fatigue resistance parameter Np. Initial test results thus ascertained the need for low temperature binder performance as a most relevant and critical factor for characterizing binder performance in relation to raveling / durability problem in PA.