Surface-Free Energy and Fatigue Performance of Hot-Mix Asphalt Modified with Nano Lime

Abstract

The free energy of asphalt cohesion and of adhesion at the interface of the asphalt binder and aggregate are the main parameters that affect mix asphalt fatigue failure in dry and wet conditions. The free energy of cohesion and adhesion within the mix asphalt system can be calculated if the components of the free energy of the adhesion at the interface of asphalt binder and aggregate are clear. Hence, in the present study, the components of the free energy of the adhesion at the interface of the asphalt binder and aggregate were calculated using a universal sorption device and Wilhelmy plate tests, respectively. In addition, an indirect tensile fatigue test was used to determine the fatigue life of mix asphalt. The materials used in this study include asphalt binder with a penetration rate of 85/100 and Nano lime as its modifier. The use of inexpensive nanomaterials such as Nano lime is one way to reduce the fatigue-cracking potential of asphalt mixtures. The results showed that using Nano lime increases the free energy of cohesion and adhesion and, therefore, improves mix asphalt resistance against fatigue cracks in the asphalt binder membrane and the interface of the asphalt binder and aggregate, respectively. In addition, the results of an indirect tensile fatigue test indicated that mix asphalt modified with Nano lime has a greater fatigue life than control mix asphalt in both dry and wet conditions. However, the effect of Nano lime is higher on mix asphalt containing acidic aggregates.