Acoustic near-field technique for characterization of bitumen and polymer processing

A conical resonator using the acoustic near-field technique has been designed and developed. The characterization of liquid media by this resonator permitted to relate the electrical measurement parameters Δf and Δ(1/Z) to the density and viscosity of the analyzed solutions. The study of the changes of the resonance features of the resonator permitted the characterization, without discontinuity, of the evolution of the rheological properties of polymer processing and bitumen as function of temperature and depth penetration. The variation Δ(1/Z) of the inverse of the maximum of the real part of electrical impedance at resonance as a function of the load, i.e. the media immersing the resonator is linear. This linearity predicted by theory is confirmed in experiments for bitumen as a function of temperature and depth penetration. Thus, the experimental measurements agree with the results expected from the modelling of the resonator.