Suitable Specimens for Measuring the Fracture Toughness of Asphalt Mixtures

Researchers have used different shapes of specimens to investigate fracture toughness of asphalt mixtures. Among these, specimens with circular shape are usual because of ease in preparation from conventional gyratory and marshal compactors. To investigate the crack growth in asphalt accurately, mode I (opening mode) and mode II (shear mode) must be considered simultaneously. In this paper the specimens with two types of crack configuration are suggested for mixed mode fracture studies of asphalt mixtures. These proposed specimens are: semi-circular bend (SCB) specimens with an inclined edge crack subjected to symmetric bending load and semi-circular bend (SCB) specimens with a vertical edge crack subjected to asymmetric bending load.