Improving the Fatigue Resistance for Hot Mix Asphalt Surface Course Mix

摘要

The objective of this study was to improve Hot Mix Asphalt (HMA) fatigue life without compromising rutting resistance and mix stiffness. The fatigue resistance of Superpave? mixes were investigated for use as surface course materials. The effects of three key design variables and their interactions were quantified: aggregate type, binder type, and binder content. The methodology included three experimental tests: four-point bending, dynamic modulus, and Hamburg Wheel Rut tests. Two types of aggregate were examined: Superpave? SP12.5 and high-friction SP12.5 FC2. A modified (PG Plus) and an unmodified binder were incorporated at both the optimum binder content and the optimum plus 0.5 percent. The results showed that the fatigue resistance, rutting resistance, and stiffness of HMA surface mixes were sensitive to aggregate type, binder type, and binder content. A specific combination of these variables' positive effects can lead to superior fatigue resistance without significant negative effect on the mixture resistance to other distresses. The best mix in fatigue performance incorporated the regular 12.5 mm aggregate and the PG Plus binder at the optimum binder content plus an additional 0.5 percent. The study outcomes can lead to HMA design that mitigates fatigue cracking with a proper rutting resistance.