Numerical Evaluation of Semicircular Bending Test Variability

Abstract

The semicircular bending (SCB) test has received significant attention as a fracture test for asphalt concrete (AC) mixtures. This study focuses on the variability of the SCB test, considering several factors, including mix gradation (Superpave and coarse matrix high binder), aggregate shape, air voids, aggregate type (granite, hard limestone, and soft limestone), and interface properties. The SCB test was modeled using a discrete element method approach to analyze the fracture behavior of the AC mixture. A total of 1 cases were produced for each mix combination, for which the interface property was set the same as that of the mastic. The effect of the interface was studied by generating 5 cases for each mix with some specific aggregate types. The generation of aggregates and air voids within the internal structure was done randomly. The simulation results suggested that the initiation of cracks and their propagation through the sample are related to the location of aggregate and air voids within the specimen. Furthermore, the aggregate-mastic contact bond increased the strength of the AC mixtures and reduced the coefficient of variation for several cases.