Abstract
Asphalt concrete is a heterogeneous material containing a viscoelastic bituminous matrix and elastic aggregates. During fatigue testing in the laboratory, the material stiffness decreases as a result of increase in temperature due to self-heating. The objective of this study was to quantify such self-heating, during fatigue testing, as one of the biases affecting the fatigue life estimation of bituminous materials. A heterogeneous approach, which consists of separating the viscoelastic matrix from the elastic aggregates, has been adopted. According to a complex domain approach, a finite element simulation of a cyclic mechanical loading is proposed by taking into account the dissipated energy, internal thermal evolution, temperature dependence of the matrix stiffness and the heat transfer process. In considering a thermomechanical coupling, the numerical simulation results indicate that dissipated energy in the bituminous matrix is influenced by material heterogeneities. A higher dissipated energy can be observed in thin matrix films, where the strain level exceeds that of thicker films. An estimation of temperature evolution using dissipated energy as a heat source is in a good agreement with experimental results. Local temperature variations are dependent on the local heat source, the thermal properties of each phase and aggregate distribution.
Disclosure statement
No potential conflict of interest was reported by the authors.