Calculation of Viscous Energy Dissipation in Asphalt Pavements

This paper presents a method to evaluate the energy dissipation in the pavement, induced by the viscous behaviour of bituminous constituents. The introduced method starts from the experimental characterization of each material and goes to the determination of stress and strain field, as well as viscous dissipated energy, in a pavement structure under a rolling wheel. A classical French pavement structure is considered as an application example. First, the behaviour of bituminous materials is characterized with advanced complex modulus tests. Second, a rheological model is used to describe the linear visco-elastic behaviour of bituminous materials. This model was previously developed at the Civil Engineering and Buildings Department of University of Lyon/ENTPE and has already shown its ability to describe completely and precisely the observed behaviour of bituminous materials. In order to make calculation the Finite Element software is then used in a third step, with the previous material model. Detailed hypotheses to perform the simulation of a rolling wheel on the pavement structure are explained. Results of the simulation are presented in terms of dissipated energy inside the pavement for a 40 ton truck. To give an order of magnitude, an estimation of the fuel consumption excess is given. Different temperature and vehicle speeds are considered. The Time Temperature Superposition Principle has been applied to estimate the dissipated energy at any temperature and vehicle speed. The simulation results show that energy dissipation in bituminous pavement due to the rolling weight of the considered 40 ton truck may induce a fuel consumption excess of a few percent for very unfavourable climatic conditions.