Dynamic modulus test and master curve analysis of asphalt mix with trapezoid beam method

Abstract

In order to study dynamic mechanical properties of asphalt mix under two-point bend load, and the impact of load level to dynamic modulus, trapezoid beam method is employed to conduct dynamic modulus tests on asphalt mix SAC13 (Stone Asphalt Concrete with nominal maximum aggregate size 13 mm). Impacts of temperature, frequency and asphalt material on dynamic modulus and phase angle are analysed: dynamic modulus decreases as temperature increases or frequency decreases, while phase angle increases as temperature increases or frequency decreases. SBS polymer modifier can improve mechanical property of asphalt material, as a result, improve pavement performance of asphalt mix. Master curve of dynamic modulus is plotted based on temperature–time superposition principle, using non-linear least square fitting method. Shifting factor lg(αT) is calculated, and master curve of phase angle is also plotted. Influence of load level to dynamic modulus is investigated, two components regressed equation of dynamic modulus is conducted and master surface of dynamic modulus is constructed. The dynamic mechanical and viscoelastic property of asphalt mix is analysed.