Multiscale Damage and Failure Behavior of Drainage Asphalt Mixture Under Multifactor

Area of Science:

• Materials Science
• Civil Engineering
• Computational Mechanics

Background:

• Drainage asphalt mixtures are crucial for pavement performance but susceptible to damage and failure.
• Understanding multiscale damage mechanisms under various factors is essential for improving mixture durability.
• Existing fatigue models require validation for specific asphalt mixture characteristics.

Purpose of the Study:

• To investigate the multiscale damage and failure mechanisms of drainage asphalt mixtures.
• To compare the applicability of different fatigue models for these mixtures.
• To analyze the influence of traffic loading, hydrodynamic pressure, mortar aging, and interfacial attenuation on mixture integrity.

Main Methods:

• Macroscopic fatigue tests.
• Mesoscopic finite element simulations.
• Microscopic molecular dynamics simulations.
• Comparative analysis of fatigue models based on strain, stress, and indirect tensile modulus slopes.

Main Results:

• The fatigue model using indirect tensile modulus slopes demonstrated high applicability across various void rates and gradations.
• A significant increase in damage and failure was observed when traffic loading exceeded 0.8 MPa.
• Hydrodynamic pressure above 0.3 MPa markedly promoted damage and crack extension, particularly around voids and aggregates.
• Mortar aging influenced damage distribution, while interfacial attenuation led to increased interface damage and complex mortar stress redistribution.
• Coupled effects determined crack propagation paths, resulting in aggregate stripping with or without mortar coverage.
• Van der Waals forces govern interface adhesion; aggregate's affinity for water over asphalt weakens adhesion.

Conclusions:

• The indirect tensile modulus-based fatigue model is highly suitable for drainage asphalt mixtures.
• Traffic loading and hydrodynamic pressure are critical factors driving mixture damage.
• Interfacial properties and mortar aging significantly influence failure modes, with implications for pavement design and maintenance.