Influence of Nano-Modifiers on Healing and Fatigue Properties of Asphalt Binders

This study is centered on assessing the influence of nano-modifiers on healing and the fatigue properties of asphalt binders. Nano-modified binders were prepared by incorporating three nanomaterials (i.e., nanoclay, nanosilica, and nanoalumina) into performance grade (PG) 58-22 and PG 76-22 binders at 1%, 3%, and 4% dosages by binder weight. The binders’ fatigue life was evaluated using the conventional linear amplitude sweep test by obtaining the number of cycles to failure corresponding to 2.5% strain. The self-healing capability of nano-modified asphalt binders was assessed by employing different rest periods (10, 20, and 30 min) and damage levels (25%, 37.5%, and 50%) in a linear amplitude sweep healing test. It was observed that nanoclay was the best performing modifier, followed by nanosilica and nanoalumina. Also, the healing capability of the binders was found to improve with the addition of rest periods that is, 10 and 20 min, beyond which it again starts decreasing. Moreover, the damage level of 25% was found to be most effective for introducing rest periods, which can be considered as the micro damage zone. Finally, the nanoclay at higher dosages (4%), 20 min rest duration, and 25% damage level was recommended as the ideal combination for self-healing in the asphalt binders based on the outcomes of this study.