Rutting response of hot-mix asphalt to generalized dynamic shear moduli of asphalt binder

摘要

In this paper, a stiffness indicator of Generalized Dynamic Shear Modulus (GDSM) of asphalt binders is introduced to study the rutting resistance of unmodified and polymer-modified asphalt binders. Seven binders of two unmodified and five SBS-modified binders are tested. At 60°C, the data of peak shear stress and corresponding peak shear strain are obtained for each binder by the Dynamic Shear Rheometer (DSR). In the linear viscoelastic region of binders, the GDSM is calculated on the basis of the constitutive shear stress-strain equation that is obtained by fitting the Box-Lucas model to experimental data. Two kinds of bituminous mixtures classified by the type of aggregate gradation are used to evaluate the rutting potential. For each gradation, the aggregate is blended with the seven binders. For each mixture, single binder content is employed so that differences in rutting depth can be investigated, depending on various GDMS values of the binders. The rutting depth of mixes is tested with the Asphalt Pavement Analyzer (APA) at 60°C and the correlation between the average rutting depth and the GDSM is established. Results indicate that for two kinds of mixtures, there exists a good correlation between the GDSM and the average rutting depth. It is confirmed that GDSM is useful as a stiffness indicator for the evaluation of rutting resistance of binders. The constitutive equation of shear stress-strain can be obtained by fitting the Box-Lucas model up to the peak shear stress, which represents an explicit mechanistic implication.