ABSTRACT
Cracking due to tensile stress is a typical damage pattern, which plays a crucial role in the pavement durability. Cracking propagation is always accompanied by the evolution of microstructure of asphalt mixtures, most of time they are in a coupled system. Here, the indirect tensile (IDT) test, numerical simulation, and together with image processing technique were conducted to record the variation trajectory of microstructure and stress distribution. Further, a relationship between microstructure evolution and crack propagation was established. Based on the variation of defects area and CT values with loading time, it is shown that the mixture experiences a compaction stage before cracking occurred. Besides, most vertical direction cracks initiate at the interface due to the rotation of aggregate. Some aggregates are even fractured because of the squeezing force when rotation was restrained. Therefore, interface strength and aggregate strength have a great influence on cracking propagation behavior of asphalt mixture.
