Determination of bituminous mixtures linear properties using ultrasonic wave propagation

The results of an experimental campaign performed on several bituminous mixtures using ultrasonic wave propagation are presented in this paper. With regard to compression “P” waves, two methods of measurement which allow obtaining complex moduli of mixtures are performed and compared, namely “direct measurement of flying time” and “Impact Resonance test”. The back calculated moduli obtained at different temperatures (−19 °C, 0 °C, 20 °C and 40 °C) show a good fitting compared to both classical tension–compression complex modulus tests and modeling using the linear viscoelastic model “2S2P1D”, proposed by the authors. The observed relative errors are a bit higher at high temperature. In a second experimental part, the direct measurement of flying time method is used for shear “S” waves. Considering isotropy hypothesis, the Poisson’s ratio of the specimens could be obtained. The measurements at 20 °C fit well the modeling if the difference between “P” and “S” wave frequencies is taken into account for the linear viscoelastic back analysis.