EXPLORING THE EFFECT OF NANOMODIFIERS ON THE SELF-HEALING PROPERTY OF ASPHALT BINDERS

This study aimed to investigate the influence of nanomodifiers on the self-healing of asphalt binder. Two base asphalt binders, PG 58-28, and PG 64-22 were modified with nanoalumina, nanoclay, and nanosilica at 1%, 3%, and 4% dosages by weight of binder. After performance grading and storage stability tests, Fourier Transform Infrared Spectroscopy (FTIR) assessed changes in unaged and short-term oxidized binders. Additionally, thermodynamic properties i.e., Surface Free Energy (SFE), of nanomodified binders were assessed via the sessile drop method. Finally, this study conducted healing characterization using the Modified Time Sweep and Linear Amplitude Sweep Healing tests. Moreover, this study looked into nanomodifiers on mitigating the negative impact of oxidation on self-healing capabilities of asphalt binder. The findings showed that nanoparticles had binder-specific and dose-dependent effects on SFE. Notably, oxidation had a lesser impact on PG 58-28 than PG 64-22 after nanomodification. Furthermore, nanomodification increased molecular mobility and aliphatic chain length slightly in PG 58-28, particularly with nanosilica and nanoclay at higher concentrations. Healing mastercurves, developed for PG 58-28 nanomodified binders under pre-failure conditions, demonstrated that nanomodifiers reduced impact of oxidation on binder healing potential. These results remained consistent across lower reduced rest periods for various nanomodified binder concentrations.