Evaluation of low-temperature fracture properties of asphalt mixtures using SCB fracture test and finite element method (FEM)
摘要
Asphalt mixture cracking is one of the major factors affecting the performance of asphalt pavement, which will significantly reduce the pavement service life. In this study, the cracking resistance of asphalt mixtures was evaluated by combining the lab semi-circular bending (SCB) fracture test and the finite element method (FEM) through the indexes of stress intensity factor, fracture energy, and J-integral. The effects of asphalt binder, gradation and notch length on the cracking resistance of asphalt mixtures were analyzed. The results show that the maximum tensile stress appeared in the bottom center of the SCB specimen and gradually decreased along the diameter and thickness directions, and the compressive stress mainly appeared in the semicircular specimen on the outer circumference, forming a curved region along the pivot point. An expression for the stress intensity factor at the crack tip of the specimen with notch lengths was established. In addition, it is beneficial to select aggregates with large size and improve the asphalt binder properties to improve the cracking resistance of asphalt mixtures. Besides, the tensile stress, KIC and fracture energy of asphalt mixtures decreased almost linearly with the increase of notch length. The research results provide a reference for improving the cracking resistance of asphalt mixtures.