Effect of graphene oxide in different phases on the high temperature rheological properties of asphalt based on grey relational and principal component analysis

Nanomaterials such as graphene oxide (GO) are frequently applied in electronic, biological, and environmental areas, among others. In recent years, GO has also been increasingly used in pavement engineering. In this study, two different states of GO (solid and dispersant) were used as modifiers of asphalts to determine which might be the better modifier. They were mixed with base asphalt and styrene–butadienestyrene (SBS) modified asphalt to produce GO modified asphalt and GO/SBS modified asphalt. The storage stability and high temperature rheological characteristics of asphalt were tested using a softening point meter, Brookfield viscometer, and dynamic shear rheometer (DSR). Grey relation analysis (GRA) and principal component analysis (PCA) were used to evaluate the experimental data. According to the experimental findings, adding GO can significantly increase asphalt's viscosity and storage stability. In addition, the inclusion of GO can make asphalt more elastic and increase its resilience to deformation brought on by temperature changes and stress. Through experiments, several indicators that define asphalt's high temperature performance were measured. Two indicators with the best correlation with rutting resistance of asphalt were selected by grey relation analysis: phase angle (δ) and irrecoverable creep compliance (Jnr), which are more representative for assessing the effectiveness of asphalt's rutting resistance. Using these parameters, a comprehensive score for the asphalt's high temperature performance was generated using principal component analysis. Our results indicate that adding GO can significantly raise asphalt's overall rating. The composite scores of the base asphalt modified by the liquid GO dispersion and the SBS modified asphalt were −1.39 and 2.12, respectively, while those modified by solid GO were −1.58 and 2.05, respectively. This shows that GO dispersion offers better modification effects. Our findings demonstrate that the high temperature performance of the composite modified asphalt prepared by adding the GO dispersion to the SBS modified asphalt provides the best comprehensive scores of all asphalts.