Fatigue and Healing Characteristics of WMA–RA Blended Binders

Asphalt mixes prepared using warm-mix asphalt (WMA) technology have similar capabilities to hot-mix asphalt (HMA) mixes for reducing emissions and energy consumption along with on-par performance. Recycled asphalt (RA) mixtures exhibit superior resistance to rutting and moisture damage due to the presence of stiff aged binder, which also has negative impact on fatigue resistance. The chemical composition and flow characteristics of asphalt binders govern their ability to heal and recover from fatigue damage when subjected to rest periods and/or suitable temperatures. Fatigue and healing characteristics of WMA–RA blends were evaluated by conducting linear amplitude sweep and time sweep tests using dynamic shear rheometer. It was observed that fatigue resistance of the WMA binders improved with addition of the reclaimed asphalt pavement (RAP) binder. The influence of rest period on healing was determined by analyzing the slopes of the fatigue life versus rest period plots. It was observed that the fatigue lives of the binder increased with rest periods due to damage recovery, and the healing ability decreased with RAP binder increments. In addition, correlations were established between healing potential and various rheological and chemical composition. The healing potential of WMA–RA showed strong correlation with rheological and chemical composition including G*sinδ, surface free energy, and aging indices computed using Fourier transform infrared spectroscopy.