Inorganic Nanoparticle-Modified Asphalt with Enhanced Performance at High Temperature

Abstract

Seven types of inorganic nanoparticles were selected to modify the base asphalt used in asphalt concrete pavement. The most suitable one, silicon dioxide (SiO2), was screened out based on its excellence in improving asphalt pavement performance. SiO2 nanoparticles as a modifier, along with silane coupling agent, stearic acid, and polyethylenimine as the respective dispersants, were prepared at different levels to manufacture various nanoparticle-modified asphalt, from which the level of SiO2 nanoparticle–modified 5% SiO2+2% silane coupling agent was selected because of its outstanding performance. This nanoparticle-modified asphalt was then subjected to dynamic shear rheometer (DSR) tests and bending beam rheometer (BBR) tests to evaluate its performance when used in pavement, and scanning electron microscopy (SEM) tests, Fourier transform infrared (FTIR) spectroscopy tests, gel permeation chromatography (GPC) tests, and differential scanning calorimetry (DSC) tests to analyze the microscopic mechanism of SiO2 nanoparticles in asphalt modification. It was found that SiO2 nanoparticles can significantly improve asphalt performance at high temperatures. It was also evident from the frequency sweep test that the effect of SiO2 nanoparticles on the complex viscosity weakens gradually as the frequency increases, indicating that SiO2 nanoparticles improve asphalt performance more significantly at low-frequency conditions than at high-frequency conditions. Laboratory test results of pavement performance of asphalt concrete mixture show that SiO2 nanoparticles also considerably improve high-temperature stability and water stability of base-asphalt concrete mixture.