Damage and Healing in Fatigue Fracture

TL;DR

This paper combines experimental and theoretical methods to analyze fatigue failure in asphalt, revealing a fatigue limit, power-law lifetime dependence, and introducing models that explain damage accumulation and healing mechanisms.

Contribution

It introduces two novel models, a fiber bundle and fuse model, that accurately capture microscopic damage and healing processes in asphalt fatigue failure.

Findings

Existence of a finite fatigue limit below which no failure occurs

Power-law decrease of lifetime with load in the intermediate range

Models accurately reproduce experimental microscopic mechanisms

Abstract

We present an experimental and theoretical study of the fatigue failure of asphalt under cyclic compression. Varying the load amplitude, experiments reveal a finite fatigue limit below which the specimen does not break, while approaching the tensile strength of the material a rapid failure occurs. In the intermediate load range, the lifetime decreases with the load as a power law. We introduce two novel theoretical approaches, namely, a fiber bundle model and a fuse model, and show that both capture the major microscopic mechanisms of the fatigue failure of asphalt, providing an excellent agreement with the experimental findings. Model calculations show that the competition of damage accumulation and healing of microcracks gives rise to novel scaling laws for fatigue failure.