Research on the influence of parameters on the fracture performance of the large stone asphalt mixture based on the semi-circular bending test

Abstract

Pavement failure is a main type of road damage. To investigate the fracture performance of asphalt mixtures with large aggregates, this study utilized the semi-circular bending test to compare the specimens of LSAM-30 (the large stone asphalt mixture) and AC-13 (the fine aggregate asphalt mixture). The research focuses on examining the effects of specimen thickness, notch length, loading rate, and test temperature on the fracture performance. In the assessment of the experimental outcomes, this study employs fracture energy, J-integral, BCI, and CRI as parameters for comparison. The findings demonstrate that under the same conditions, the large stone asphalt mixture exhibits higher peak load, greater fracture energy, higher BCI and CRI values, as well as better J-integral fracture toughness in comparison to the fine aggregate asphalt mixture. At 20°C, the crack path in the large stone asphalt mixture (LSAM) circumvented the large aggregates and thus presented to be bent and long, while the crack in the fine aggregate asphalt mixture was shorter and straighter. The longer and more curved crack path in the LSAM consumed greater energy, resulting in better fracture resistance. At 0°C, the cracks in both asphalt mixtures were linear, but the large aggregate mixture required a stronger load to damage the larger aggregates. Therefore, the LSAM demonstrates a slightly better fracture resistance at low temperatures. In conclusion, the higher peak load, fracture energy, BCI, and CRI of the LSAM indicate a superior fracture performance. The longer and more curved crack path implies greater energy consumption during the fracture. As a result, the LSAM exhibits better fracture performance and resistance to pavement failure compared with the fine aggregate asphalt mixture.