Effect of Asphalt Binder Characteristics on Filler–Asphalt Interactions and Asphalt Mastic Creep Properties

Creep properties of asphalt binder and mastic are critically important to asphalt concrete’s high-temperature antirutting resistance. The Burgers and three element models were applied to determine the creep parameters of four asphalt binders and 24 mastics with varying filler volume fractions. The influence of asphalt binders and filler volume fraction on the creep compliance, J, instantaneous elastic deformation compliance, Je, delayed elastic deformation compliance, Jde, viscous flow deformation compliance, Jv, and the proportion of Je, Jde, and Jv to total creep compliance were analyzed according to the model results. A simple two-point reciprocal relative creep compliance was applied to determine the critical filler volume fraction of asphalt mastics with different asphalt binders. The physicochemical interaction between asphalt binder and filler was evaluated with the Einstein coefficient, KE. Based on Fourier infrared spectroscopy, four kinds of functional group indexes were calculated, and then associations of KE and the functional group indexes were determined by grey relational analysis (GRA). The results showed that filler volume fraction had a similar degree of influence on Je of the two kinds of modified asphalt mastics, but an obviously different influence on Jde and Jv of mastics with various asphalt binders. Nonrecoverable viscous flow characterized the deformation of matrix asphalt mastics. However, in modified asphalt mastics, elastic deformation played an important role in the initial stage of creep, and then the delayed elastic deformation constituted the principal component. Adding fillers caused an increase in the proportion of instantaneous elastic deformation and delayed elastic deformation, while the viscous flow deformation decreased significantly. The critical filler volume fraction was 0.273–0.426 for the four asphalt binders. Grey relational analysis results showed that the influential priority of the four functional groups of asphalt on KE were as follows: sulfoxide>carbonyl>aliphatic>aromatic.