Evaluation of Low-Temperature Properties and the Fragility of Asphalt Binders with Non-Arrhenius Viscosity–Temperature Dependence

Abstract

Rotational viscosities of different asphalt binders were determined at temperatures between 80°C and 185°C. Viscosity–temperature dependence of asphalt binders was described with the use of the Vogel–Tammann–Fulcher (VTF) and the William–Landel–Ferry (WLF) equations. The Vogel temperature (T_v) and the glass transition temperature (T_g) for different asphalt binders were determined by fitting experimental values of viscosity at different temperatures with these two equations. For asphalt binders, the difference between T_v and T_g was about 40K. Effects of asphaltenes, aging, chemical modification, and polymer content on these temperatures were evaluated. As asphaltene content increased, both temperatures, T_v and T_g, increased. Different polymers showed different effects on these temperatures. The values of T_v and T_g were correlated with the critical cracking temperature (T_cr) determined through use of a bending beam rheometer and a direct tension tester. The results suggested that the correlations between T_v, T_g, and T_cr could be used to determine T_cr from the rotational viscosity results tested at high temperature. With simple rotational measurements, a quick estimation of T_cr of asphalt binders could be obtained. Liquid fragility theory was also used to study T_g of asphalt binders. Parameters determined with the VTF and WLF equations indicated that asphalt binders behaved as fragile liquids because of their non-Arrhenius behavior in the temperature range studied.