Research on Aging Behavior and Microscopic Characteristics of Asphalt Binder Based on Grey Relational Theory
摘要
This study focused on investigating the influence of aging on asphalt from different aspects, and revealing the relationship between microstructure, chemical functional groups and macro properties of asphalt. The thin film oven tests (TFOT) were conducted to base asphalt and stytrene butadienestyrene (SBS) modified asphalt, then the softening point, ductility and penetration of asphalt before and after aging were measured. The rheological properties of asphalt under different temperatures were evaluated by dynamic shear rheometer (DSR), the complex shear modulus, phase angle and rutting factor of asphalt after aging were obtained and analyzed. The multiple stress creep recovery (MSCR) was conducted to asphalt to study the stress dependence and elastic response of asphalt under different temperatures. The Fourier transform infrared (FTIR) spectroscope test and atomic force microscope (AFM) test were performed to asphalt to study the influence of short-term aging on the functional group indexes and morphologies of asphalt. The grey relational degree between micro-parameters and mechanical properties of asphalt were discussed. The results showed that the complex shear modulus, phase angle and rutting factor of asphalt showed an increasing trend after aging tests. The deformation recovery rate (R) of asphalt after aging increased dramatically, and the non-recoverable creep compliance (Jnr) at the stress level of 3.2 kPa decreased compared to asphalt before aging, and SBS modified asphalt showed a positive effect on the elastic response stability of asphalt. The carbonyl index, sulfoxide index, Derjaguin-Muller-Toporov (DMT) modulus and roughness of asphalt increased after aging, while the adhesion force decreased. These changes can be attributed to that during short-term aging tests the volatile light components in asphalt evaporated, and the structure within the asphalt was reorganized, which led to a more ordered and regular structure of asphalt. The grey relational degree showed that DMT modulus and adhesion force exhibited a good correlation with complex shear modulus, phase angle, rutting factor and non-recoverable creep compliance, and this result indicated that the DMT modulus and adhesion could effectively characterize the macroscopic viscoelastic properties and high temperature properties of asphalt.