Towards a viscoelastic mechanical characterization of asphalt materials by ultrasonic measurements

This study focuses on the use of P-wave propagation measurements in order to evaluate the complex modulus, more specifically for the reversible and dissipated parts of asphalt materials. Both the wave velocity and attenuation factor have been measured by means of an ultrasonic transmission test, at frequencies between 200 and 300 kHz and temperatures ranging from -20 to 40 A degrees C. Based on this wave velocity and attenuation factor, the high-frequency complex modulus and its components are computed by considering a 2D propagation of waves in an isotropic viscoelastic medium. Results are plotted with respect to the master curve, Cole-Cole and Black spaces. The ultrasonic test results agree with results obtained by complex modulus test and then fitted by the 2S2P1D rheological model. This paper shows in Cole-Cole space that ultrasonic data can facilitate the determination of important rheological parameters as one of the two parabolic dashpots (k) and the glassy modulus E (0). The phase angle, which is also a key viscoelastic identification parameter, can be determined at high frequency in a Black space representation.