2D Mesoscale cracking simulation of partially saturated asphalt based on moisture diffusion and a cohesive zone model

ABSTRACT

The primary objective of this paper was to develop a combined model that incorporates moisture diffusion and a cohesive zone model, addressing anisotropic and loading-rate dependent cracking within partially saturated asphalt. Utilising X-ray CT scan, cross-sectional slices of asphalt were acquired and converted into vector images through Matlab and AutoCAD, forming a digital asphalt sample. Moisture concentration in the asphalt, after different immersion durations, was quantified by Fick's law. A sequentially coupled model of moisture diffusion and fracture investigated the effect of immersion duration, anisotropy, and loading rate on cracking performance of the asphalt during a digital indirect tensile strength test (DITST) at 5°C. Findings revealed that moisture evolution in partially saturated asphalt proceeds through two or three stages: near-zero growth (only applicable for locations far from the initial moisture-asphalt interface), rapid growth, and a plateau. Peak load, stiffness, and fracture work in DITST exponentially reduced with immersion duration, predominantly within the first four weeks. Anisotropy led to differential DITST results when varying loading direction. Moisture damage decreased crack resistance across all directions, while increasing loading rate enhanced it. Fracture stiffness and strength exhibited comparable impacts on cracking performance at a specific loading rate.

KEYWORDS:

• Asphalt
• cracking
• cohesive zone model
• moisture diffusion

Acknowledgements

The authors would like to acknowledge the financial support from the Engineering and Physical Sciences Research Council (grant number EP/T019506/1), and the National Natural Science Foundation of China (grant number 51978229 and No. 52278450).

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data Accessibility Statement

The raw data used in this study can be made available based on reasonable requests subject to approval of the data owner.

Additional information

Funding

This work was supported by Engineering and Physical Sciences Research Council: [Grant Number EP/T019506/1]; National Natural Science Foundation of China: [Grant Number 51978229].