Prediction of Asphalt Concrete Permanent Deformation Accumulation Using the Finite-Element Method

Asphalt concrete (AC) rutting, a critical issue in flexible pavements, is traditionally estimated using mechanistic responses from layered elastic theory and empirical regression equations, which limit accuracy and necessitate extensive local calibration. To address these limitations, a robust three-dimensional (3D) finite-element (FE) pavement model was developed to simulate AC rutting progression. AC was characterized as viscoelastic fluid using a validated nonlinear Burger model containing a power law dashpot to compute permanent deformation. The material model was numerically derived and integrated into an existing validated 3D FE pavement model. This model accurately accounts for tire loading complexities, material properties, temperature variations, and layer interactions, ensuring realistic pavement behavior representation. To efficiently simulate rut progression, the load pass approach (LPA) was introduced, enabling the application of cyclic loading while maintaining computational efficiency and accuracy. To verify the model, a total of 24 simulations were completed, incorporating different pavement sections, material properties, traveling speeds, load types, and temperatures to assess AC rutting. The rut accumulation predicted using the power-law model and LPA showed trends that are logical and closely aligned with real-world observations. Hence, the proposed robust mechanistic pavement model for AC rutting can serve as a reliable tool for pavement design applications.