Experimental Investigation And Numerical Simulation For Fracture Of Semi-circle Bending Specimen Of Asphalt Mixture

The asphalt pavements have been widely used in high-grade highway due to manyadvantages. With the rapid development of traffic, both the traffc volume and the numberof heavy vehicle keep increasing in recent years. Therefore a number of distresses can befound in the early service time of the asphalt pavements. Crack is one of the maindistresses. It is a critical step to improve the design and enhance the anti-cracking capacityfor asphalt pavement for transportation safety. So it is significant for the asphaltpavements to research the behaviour and mechanism of crack.The crack behavior and mechanism of the asphalt mixture with different notchdirection considering the advantages of semi-circle specimen are investigated by couplingthe experimental and numerical method. The research content includes that:(1) The semi-circle bending (SCB) tests for single-edged notch specimenscontaining different orientations are performed. The experimental results show that notchorientation has important effects on the load-displacement curve and crack propagationpath. The crack propagates approximately along a straight-line when the orientation angleis equal to zero. However, the crack propagates from the crack tip with a zigzag anglerelative to the notch for other cases. The bigger the orientation angle, the bigger the zigzagangle.(2) A meso-scale heterogeneous model of asphalt mixture semi-circle bendingspecimen is built by using the random aggregate generation. The stress contours aroundcrack tip are analyzed, and then the effects on stress intensity factor for differentorientation are also investigated. (3) With the help of CZM model, the damage and cracking process for differentorientation notched specimens are simulated. Both the simulated load-displacement curveand crack propagation path are compared with experiments. Furthermore, The mesoscopiccracking process of asphalt mixture is analyzed. At last the mechanism of crack initiationand propagation is discussed.