Linear and nonlinear thermomechanical behaviour of interface between bituminous mixtures layers: results from 2T3C apparatus and modelling

Thermomechanical behaviour of interface of pavement structures was experimentally characterized using the 2T3C (French acronym for "Torsion-Tension-Compression on Hollow Cylinder") apparatus developed at ENTPE, combined with 3D Digital Image Correlation (3D-DIC). Tested samples are double-layered hollow cylinders with an interface composed of bitumen emulsion and two layers made of different materials. In this study, cyclic torsion is applied on tested samples at combinations of five temperatures (from 0 degrees C to 40 degrees C) and five frequencies (from 0.01 to 1 Hz). Two different levels of global strain amplitudes are applied on samples (50 and 200 mu m/m). The experimental results show that Time-Temperature Superposition Principle holds for all tested conditions. The linear viscoelastic model 2S2P1D perfectly simulates the behaviour of interfaces for the lower global strain amplitude, but not for the higher global strain amplitude because of an underestimation of phase angle. Successful simulation of phase angle values were obtained using the DBNPDSC model.