Understanding interfacial interaction characteristics of asphalt nanocomposites reinforced with diamond nanothread and carbon nanotube

Abstract

Diamond nanothreads (DNT) and carbon nanotubes (CNT) have emerged as promising reinforcement materials for asphalt. However, the interfacial properties between DNT/CNT and asphalt remain poorly understood, hindering the advancement of DNT/CNT-modified asphalt nanocomposites. In this study, the pullout tests are conducted on asphalt nanocomposites reinforced with DNT, nitrogen-doped diamond nanothread (NDNT), and CNT, to analyze the pullout performance and reinforcing mechanisms across various temperature ranges. The findings reveal that CNT modified asphalt nanocomposites exhibit superior pullout performance compared to those reinforced with DNT, primarily due to π-π stacking interactions that facilitate the wrapping of asphalt molecules around the CNT surfaces. Among the DNT variants, the DNT2 modified asphalt nanocomposite demonstrates the highest pullout performance, attributed to its helical structure that enhances mechanical interlocking within the asphalt matrix. Notably, NDNT shows the highest binding energy relative to both DNTs and CNTs, stemming from interactions between hydroxyl groups on asphaltene-phenol and nitrogen atoms on NDNT, leading to the formation of O-H···N hydrogen bonds. Density functional theory (DFT) calculations indicate that nitrogen doping modifies the electronic structure of NDNT, resulting in localized negative charges that enhance its overall electronegativity.