Investigation of linear and damage-coupled viscoelastic properties of sustainable asphalt mixture using a micromechanical finite element approach

This paper presents a microstructure-based finite element model by incorporating elastic aggregates and viscoelastic sand mastic. The microstructure-based finite element (FE) approach was used to predict the linear and damage-coupled viscoelastic properties of reclaimed asphalt mixture. The two-dimensional (2D) microstructure of asphalt mixture was obtained from the scanned image of a smoothly sawn surface of a reclaimed asphalt pavement (RAP) mixture specimen. In the microstructure, the sketches of highly irregular aggregates were converted into polygons. The whole microstructure model was divided into highly irregular aggregate and sand mastic subdomains. The finite element mesh was generated within each subdomain. The deformation of the aggregate and mastic subdomains was connected through the sharing boundary nodes. Linear and damage-coupled viscoelastic finite element model was developed with displacement-based incremental formulation. The linear and damage-coupled viscoelastic simulation was conducted on the image sample of test specimen under different sinusoidal force loading frequencies. The uniaxial compression simulation results showed creep deformation constant cyclic force loading amplitude and damage-coupled viscoelastic responses have larger creep deformation. Simulations under different loading frequencies found compression strain deceases with loading frequencies due to less relaxation time. Copyright ASCE 2007