Meso-Structural Modeling of Asphalt Mixtures Using Computed Tomography and Discrete Element Method with Indirect...

Area of Science:

• Civil Engineering
• Materials Science
• Computational Mechanics

Background:

• Understanding asphalt mixture behavior under load is crucial for pavement durability.
• Existing models often simplify the complex meso-structure of asphalt, limiting predictive accuracy.
• The interaction between aggregates, asphalt mortar, and voids significantly influences mechanical response.

Purpose of the Study:

• To develop and validate a meso-structural modeling approach for asphalt mixtures using computed tomography (CT) and the discrete element method (DEM).
• To investigate internal force transfer, crack propagation, and failure mechanisms in SMA-13 asphalt mixtures under indirect tensile (IDT) loading.
• To analyze the influence of temperature and loading on internal forces and identify critical factors for crack resistance.

Main Methods:

• Integrating CT imaging for realistic aggregate morphology with DEM for discrete particle simulation.
• Numerical simulation of indirect tensile (IDT) tests on SMA-13 asphalt mixtures.
• Post-processing of simulation data to identify force chains, analyze crack paths, and quantify internal forces.

Main Results:

• Validated CT-DEM simulations against experimental IDT test results.
• Identified primary vertical and horizontal force chains governing fracture progression.
• Observed higher internal forces in aggregate skeletons compared to mortar, with temperature significantly impacting both.
• Characterized meso-crack evolution in three distinct phases and determined the fracture-affected zone.
• Highlighted the critical role of the aggregate-mortar interfacial transition zone in crack resistance.

Conclusions:

• The CT-DEM approach accurately captures the meso-structural behavior of asphalt mixtures.
• Force chain interactions and aggregate-mortar interfaces are key determinants of asphalt pavement failure.
• Temperature and loading conditions significantly influence internal force distribution and crack initiation/propagation.