Fracture properties of asphalt mixtures using semi-circular bending test: A state-of-the-art review and future research

Abstract

Although many fracture test procedures are available, the semi-circular bending (SCB) test has drawn a growing interest in the pavement community due to its simplicity, reproducibility, and flexibility in testing and evaluation. In this direction, fracture properties of asphalt mixtures are currently being evaluated using SCB test with the application of fracture mechanics to characterize low-temperature and fatigue fracture using the standard semi-circular bending protocols. However, several research studies have employed various sets of specifications suiting practical convenience that calls for a critical review of the procedures that have been followed to date. This review article presents the current state-of-the-art regarding the utilization of SCB test to evaluate fracture properties of different asphalt mixtures. The fundamental assessment of fracture through the SCB test, which was based on load-deformation characteristics of asphalt mixes, was discussed in detail. The analytical procedures employed to deduce fracture parameters for asphalt mixes to understand the fracture performance was also documented. Overall, the SCB test procedure was found to be a promising crack propagation assessment candidate to evaluate asphalt mix fracture properties. It was recommended that future studies must concentrate on developing cyclic SCB test to investigate the dynamic fatigue behaviour along with viscoelastic properties. Certainly, there exists scope for advancing the current state-of-the-art pertaining to the SCB test procedure that actually simulates the field performance characteristics in conjunction with mechanistic based flexible pavement designs.