Speaker
Description
Abstract. Micromechanical modelling through the Discrete Element Meth-od (DEM) is adopted for the study of bituminous materials given its capa-bility to replicate complex microstructures behaviour. Typically, DEM models of bituminous materials consist of an assembly of randomly dis-tributed spherical rigid particles which interact using elastic and/or simple viscoelastic contact models, and individual aggregates are represented by single particles. However, recent years have witnessed a notable surge in re-search efforts aimed at incorporating true particle morphologies into numer-ical models. In the context of this research, an existing 3D DEM model for bituminous materials has been refined with the representation of mineral aggregates with realistic particle shapes. To achieve this, a digital library of aggregate shapes was constructed from X-ray computed tomography (CT) scans. An adaptive image-processing technique was employed to isolate the aggregates in the CT images, and the Delaunay method was used to create a 3D surface model of the aggregates. Several virtual aggregates with varying sizes were selected from this library to mirror the gradation of coarse aggre-gates in the 3D DEM asphalt model. Each virtual aggregate was discretized using smaller spherical particles, with its deformability given by its inner particle contacts. To evaluate the effectiveness of this enhanced approach, numerical assemblies featuring realistic particle shapes were subjected to a cyclic loading protocol. Overall, realistic particles shapes increased the stiffness modulus and decreased the phase angle of numerical specimens, and the effect was greater with a finer discretization of aggregates. The out-comes clearly demonstrate the importance of this numerical improvement to accurately simulate the bituminous mixture behaviour.
