Molecular composition and mechanical properties of bitumen : a molecular dynamic study
Claire Lemarchand, Université de Roskilde
Bitumen is one of the essential components of roads. Its mechanical properties need to be controlled in order to reduce the rolling resistance developed between the tyre and the road as a vehicle is travelling on the road.
In this presentation, I will speak about the link between the molecular composition and the mechanical properties of « Cooee » bitumen. This model bitumen is composed of four realistic molecule types: saturated hydrocarbon, resinous oil, resin, and asphaltene. It is studied with molecular dynamic (MD) simulations. Asphaltene molecules are large and flat aromatic molecules.
The molecular dynamic simulations are able to reproduce the aggregation of asphaltene molecules into nanoaggregates. The size of the nanoaggregates was estimated in the simulations and shown to be comparable to experimental results. The dynamics of the nanoaggregates was precisely quantified in MD, giving new insights about their formation. Finally, the influence of these nanoaggregates on the bitumen mechanical properties and overall dynamics was investigated. This last part of the work enables us to set some rules about bitumen chemical composition to lower its viscosity.