Assessment of Self-Healing Capability, Thermodynamic Properties, and Chemical Properties of Nanomodified Asphalt Binders

Abstract

This study aimed to investigate the suitability of nanomodifiers or particles in enhancing the self-healing in asphalt binders characterized by the change in thermodynamic property and the chemical changes under short-term oxidation aging. Two base asphalt binders having grades PG 58-28 and PG 64-22 were modified with three nanomodifiers, namely, nanoalumina, nanoclay, and nanosilica, at 1%, 3%, and 4% dosage by weight of binder. The fatigue damage and the healing potential were quantified based on the linear amplitude sweep healing (LASH) test, while the Fourier transform infrared spectroscopy (FTIR) test was utilized to assess the changes in the chemical structure of the binders as a result of nanoparticle incorporation. Additionally, the sessile drop method was employed to examine the thermodynamic property, i.e., surface free energy (SFE), of the nanomodified binders prepared through various sample preparation techniques. The findings highlighted that the nanoparticles had a dissimilar effect on different binders and varying dosages in terms of the SFE parameter. Also, the softer binder (PG 58-28) showed better resistance against oxidation after nanomodification, as compared to the PG 64-22 binder, as evident from higher SFE values, especially with 1% and 3% nanosilica. Furthermore, nanomodification improved molecular mobility and aliphatic chain length in the PG 58-28 binder, specifically nanosilica and nanoclay at higher concentrations. Meanwhile, the healing master curves developed under prefailure conditions for PG 58-28 nanomodified binders demonstrated that nanomodifiers comparatively reduced the impact of oxidation on the healing potential of binders, with higher-percentage healing parameters. These healing master curves were comparable at lower reduced rest period for varying concentrations of nanomodified binders.