High-Temperature Properties of Hot Mix Asphalt Modified with Different Nanomaterials

Rutting is a predominant distress in asphalt pavements, particularly in hot climatic regions. This study systematically investigated the high-temperature performance of hot mix asphalt modified with five nanomaterials, namely, nano-silica (NS), nano-alumina (NA), nano-titanium (NT), nano-zinc (NZ), and carbon nanotubes (CNTs), under consistent laboratory conditions. Modification dosages were selected up to 10% for NS, NA, and NT, and up to 5% for NZ and CNTs. The experimental methodology comprised the following: (i) binder rheological characterization through rotational viscosity, G*/sinδ, and multiple stress creep recovery (MSCR) to quantify rutting susceptibility; (ii) chemical and microstructural assessments using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM); (iii) mixture-level evaluation via repeated-load axial testing coupled with digital image correlation (DIC) to monitor permanent microstrain evolution; and (iv) rutting performance over a 20-year period using the VESYS 5W predictive model. A cost-performance analysis was further incorporated to assess the economic viability of each nanomaterial. The results demonstrated that nanomodification substantially improved rutting resistance, consistent with reductions in non-recoverable creep compliance and permanent microstrain. Among additives, the 8% NS mixture exhibited the most favorable performance, maintaining a present serviceability index (PSI) of 2.5 after 20 years, whereas the un-modified mixture dropped below the failure threshold within a few years. These findings confirm that nanomaterial selection and dosage can meaningfully enhance the structural and performance of asphalt pavements.