Discrete element modelling of hot mix asphalt complex modulus using realistic aggregate shapes

To assess the mechanical response under traffic of asphalt mixtures, a typical practice is to perform a complex modulus test. In this work, the complex modulus test is reproduced numerically for an asphalt mixture by 3D simulations carried out with the LMGC90 code. A viscoelastic contact law is used to handle the interaction between particles with irregular shapes. The numerical aggregates were generated using the particle size distribution (PSD), the flakiness index (FI), and statistic data of actual aggregates, without using complex imaging techniques. Experimental and numerical testing campaigns were conducted for the complex modulus test on trapezoidal samples in a two-point bending (2PB) configuration. The numerical model was able to reproduce the mechanical performances obtained during the experimental tests, regarding the viscoelastic properties of the material. The influence on the mechanical performances of particle shape considering irregular aggregate was analysed.