Investigation of Asphalt Mixture Characteristics against Pure Mode III Fracture

By the research on the behavior of fracture toughness in asphalt mixtures, it has been suggested that several components have been proposed to test the mode III (KIIIc) fracture toughness of asphalt mixtures. But until now, a standard piece not been provided for testing fracture toughness (KIIIc) of asphalt. Such specimen should have appropriate geometric and loading conditions. In addition, it could be compatibility with the most common features in the inherent of tested materials and provide repeatable, reliable and integrity data of fracture resistance in asphalt mixture. ENDB is one of the specimens that could provide these items for calculating KIIIC of asphalt materials. It seems to be a good choice in comparing with other samples due to advantages such as ease of construction, cracks creation and simulation facilities of mode I loading for investigating of asphalt fracture behavior. The aim of this study was to investigate the effect of geometry and characteristics of asphalt mixtures on the behavior of ENDB fracture toughness. Using the finite element software (ABAQUS), geometry and meshing of the desired part have been performed. The result of this research can help in selecting and introducing the appropriate standard specimen and appropriate specifications of asphalt mixtures to determine the amount of KIIIC of asphalt mixtures to researchers. The important results of this research can be mentioned as the effect of thickness on the degree of fracture toughness in loading mode III. So the fracture toughness in the specimen with a higher thickness increases, and with the decrease in the percentage of air void and the test temperature, the degree of toughness of the fracture also increases.