Analytical modelling of thixotropy contribution during T/C fatigue tests of asphalt concrete with the VENoL model

Abstract

ABSTRACT The classical modelling of fatigue tests carried out in the laboratory on asphalt concrete consists in predicting the decrease in the overall complex stiffness modulus. However, this approach is limited because reversible phenomena, called biasing effects (nonlinearity, self-heating and thixotropy), develop in parallel with damage. The VENoL (T,ω,ε 0) model is already able to reproduce tests of instantaneous complex stiffness modulus for different strain amplitudes. The study carried out in this paper consists of improving it by predicting the evolution of thixotropy during fatigue tests. The modelling is based on the hypothetical property that thixotropy follows the viscoelastic path of the instantaneous complex stiffness modulus. Experimental data from continuous fatigue tests in direct T/C on cylindrical specimens and taken from the literature are used. The results obtained are encouraging because they corroborate the experimentation, but only for one level of strain amplitude imposed in fatigue.