A large experimental campaign on the characterization of the linear viscoelastic behaviour of different bituminous materials was carried out. The goal was to establish the links between the linear viscoelastic properties (which are observed in the small strain domain) of binders and those of bituminous mixes. The linear viscoelastic behaviour of bituminous binders and mixes was studied by performing complex modulus tests at different temperatures and frequencies. A unique rheological model (called “2S2P1D model”) was developed for the modelling of linear viscoelastic properties of both bituminous binders and mixes. This model consists of a generalization of the Huet-Sayegh analogical model. Analyses on test data for five binders and different mastic and mix composition, show that the introduced model fits quite well the measurements. Finally, from our first results, a transformation that is independent of the introduced model allows the mix complex modulus to be predicted easily and efficiently from the binder complex modulus.

This paper describes investigation into the change in complex modulus (norm and phase angle) during cyclic tests on bituminous mixtures. The change can be explained by four phenomena: nonlinearity, heating, thixotropy and fatigue. An experimental campaign has been performed at ENTPE laboratory in order to identify and quantify the first three phenomena. The analysis of the results reveals that the two reversible effects (heating and thixotropy) are very important and can not be ignored when interpreting fatigue tests. Nonlinearity, for the rather small strain level amplitudes considered in our experimental campaign (up to 122 μm/m), is also shown to be reversible. Heating is due to the viscous dissipated energy that heats the specimen. At the beginning of the test, temperature increase in the sample is shown to be proportional with the total dissipated energy. Thixotropy effect is quantified. In addition, it is shown that thixotropy effect can be modeled using an equivalent temperature increase.

The linear viscoelastic properties of bituminous mixtures are used to design pavement structure. Usually, only complex moduli E* (complex Young modulus) or G* (complex shear modulus) characterizing the stiffness of the materials in one direction (1D) are measured by classical tests. In this paper, the three-dimensional (3D) behavior is investigated. The complex Poisson's ratio ( ν* ) is introduced. Its evolution with temperature and frequency is studied for a bitumen, a mastic, and a mix. Experimental results show that the time–temperature superposition principle is applicable in the 3D case. The same shift factor applies for E* and ν* . The Di Benedetto–Neifar model developed at Ecole Nationale des Travaux Publics de l’Etat to simulate so far the 1D thermo-elastoviscoplastic behavior of bituminous materials has been extended to simulate their 3D isotropic behavior. Calibration of the model and comparison between simulations in the linear viscoelastic domain and experimental data are proposed.

A research including a large experimental campaign on the characterization of the viscoelastic behavior of different bituminous materials was developed. The aim is to establish the links between the viscoelastic properties (which are observed in the small strain domain) of binders and those of bituminous mixes. The viscoelastic behavior of bituminous binders and mixes has been studied by performing complex modulus tests at different temperatures and frequencies. A unique rheological model has been developed for the modeling of linear viscoelastic properties of both bituminous binders and mixes. This model consists of a generalization of the Huet-Sayegh analogical model. Analyses on test data for nine different binders and four mixes, with one mix design, show that the introduced model fits quite well the measurements. Finally, from our first results, a transformation that is independent of the introduced model allows to predict easily and efficiently the mix complex modulus from the binder one.