Homothetic behaviour investigation on fracture toughness of asphalt mixtures using semicircular bending test

• Investigated homothetic behaviour of asphalt mixtures’ fracture properties.
• Determined fracture toughness of 216 dense graded asphalt specimens using SCB test.
• Evaluated the effect of specimen thickness using mixed-level factorial design.
• Recommended specimen thickness range to obviate geometric dependency on fracture.

The objective of this study was to investigate the homothetic behaviour of asphalt mixes in respect of fracture toughness. A total of 216 samples encompassing six dense graded asphalt mixes were tested at three temperatures with four replicates per mix type using static semicircular bending test based on the AASHTO TP 105-13 protocol. A mixed-level factorial design was employed to understand the effect of variables: asphalt content, air voids, temperature, and thickness. Statistical analyses showed that the change in the thickness from 40 to 50 mm produced an insignificant change in the fracture toughness. It was also found that the selection of the specimen thickness to evaluate fracture toughness in the range of 40–50 mm was not significantly dependent on asphalt mix material properties and temperature.