Comparative modelling of indirect tensile strength of asphalt mixtures with and without considering air void characteristics

ABSTRACT

This paper aims at comparing the 3D discrete element modelling of the indirect tensile (IDT) strength of asphalt mixtures with and without considering the air void size and distribution. Micromechanical models for predicting the IDT strength of asphalt mixtures, with and without considering the air void size and distribution, were established using X-ray computed tomography and 3D discrete element method (DEM) incorporated with a cohesive zone model (CZM). The IDT strength of three asphalt mixtures were simulated at three different temperatures on the basis of these models. Simulation results were verified against known experimental IDT tests. The results show that air void characteristics affected greatly the IDT strength of asphalt mixtures, and with the same material parameters, the IDT strength with considering the real air void size and distribution was lower and closer to the experimental IDT strength than that without considering the real air void size and distribution. Furthermore, aggregate size and temperature also significantly affected the IDT strength. IDT strength increased with increasing aggregate size or decreasing temperature. Aggregate size had an increased impact on the IDT strength with increasing temperature, whereas air void characteristics had a decreased influence on the IDT strength with increasing temperature.

KEYWORDS:

• Asphalt mixture
• IDT strength
• air void characteristic
• CZM
• DEM

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors are grateful to the financial support from the Zhejiang Provincial Natural Science Foundation of China (LY15E080006).