Characteristics of morphology and tensile strength of asphalt mixtures under impact loading using split Hopkinson pressure bar

Abstract

The paper presents a study of the fracture morphology and tensile strength characteristics of asphalt mixtures under indirect tensile tests. A Split Hopkinson Pressure Bar (SHPB) and Universal Testing Machine (UTM) were utilized under the impact (27.7–93.8 s−1) and quasi-static loading modes (0.008–0.033 s−1), respectively. It was found that the bonding, cohesive, and intra-aggregate failures occurred under quasi-static loading, and even the large aggregates were broken under the impact loading. The cracks can be treated as two and three dimensional under quasi-static and impact loading modes, respectively. The temperature effect on tensile strength under impact loading was significantly less than that of quasi-static loading, and the enhancement of dynamic loading increased considerably in higher temperatures. The temperature was the major external factor to influence the brittleness of the asphalt mixture, while the influence of the strain rate was relatively small. Finally, some suggestions to improve the cracking resistance of asphalt mixtures were proposed in both loading modes.