Analyzing Moisture Susceptibility of Hot-Mix Asphalt Based on Tensile Strength Ratio, Coating Ratio, and Thermodynamic Parameters

Abstract

Concerns exist over the potential moisture damage and adhesion of asphalt mixtures. This research aims to evaluate the adhesion and moisture susceptibility of asphalt mixtures containing two nanomaterials [nano zycotherm (NZT) and nano hydrated lime (NHL)]. Various tests [tensile strength ratio (TSR), coating ratio (CR), and surface free energy (SFE)] were conducted and compared. The findings of this research indicate that the nanomaterial-modified asphalt mixtures demonstrated a higher TSR. The image processing results for the CR of the boiling water test and modified bitumen coating on the aggregate’s surface also improved. Moreover, the amounts of SFE indicated that the free energy of cohesion in modified bitumen increased substantially compared to the base bitumen. Additionally, the free energy of adhesion in the modified bitumen with limestone and granite demonstrated higher values. Consequently, the debonding energy for the bitumen-aggregate composition and the probability of stripping in modified mixtures decreased. Considering all the adhesion indices of the bitumen-aggregate composition, including SFE, CR, and TSR, the NZT-containing mixtures had higher moisture resistance than NHL.