Nanoscale modelling of mechanical properties of asphalt-aggregate interface under tensile loading

This paper presents an investigation on the elastic constants of a quartz structure, tensile stress-strain state and adhesion failure behaviour of asphalt-rock interfaces by using an atomistic modelling method. A molecular mechanics method is applied to calculate the quartz bulk elastic constants, e.g. stiffness matrix, shear modulus, Young's modulus and Poisson's ratio. Molecular dynamics (MD) simulations are employed to model the deformation and failure behaviour of asphalt-rock interfaces when subject to uniaxial tension. A 3D asphalt-quartz interface structure model is proposed in terms of density, position and thickness. The interfacial atom trajectories are visualised to represent the properties in simulations that characterise those of the asphalt-rock interface under uniaxial tension at nanoscale. Interfacial debonding characteristics or the adhesive failure are implemented with a large-scale MD simulation technology. The stress-strain relation of the interface layer under tensile loading is analysed in this study. It is found that highly anisotropic elastic properties of a quartz structure will appear from atomistic scale and tensile strength of the asphalt-quartz interface system is controlled by the stress state at the asphalt-rock interface layer. Asphalt-rock interface adhesive failure appears to be ductile at freezing environmental temperature and low strain rate.