Characterization of mode-I and mode-II fracture properties of fine aggregate matrix using a semicircular specimen geometry

Cracking in asphalt pavements causes primary failure in structure, with long-term durability issues often related to moisture damage. Fracture resistance and characteristics of asphalt materials significantly affect asphalt pavement service life. Studies have typically considered only mode-I (opening) fracture, but many observations demonstrate the significance of mode-II (sliding) fracture for better design of pavement structures and damage characterization of asphaltic materials. This study presents experimental and numerical efforts to characterize mode-I and mode-II fracture properties of a fine aggregate matrix mixture. To this end, semicircular bending tests were integrated with a digital image correlation system and extended finite element method. With limited scope and test results, this approach shows that mode-II fracture toughness is quite different from mode-I fracture toughness (approximately three times greater than mode-I), clearly indicating that mode-dependent fracture characteristics are necessary in structural design of asphalt pavements with which multiaxial fracture is usually associated.