Investigations on the crack resistance characteristics of asphalt concrete based on digital image correlation method

The evaluation of the cracking performance of asphalt concrete is essential for a comprehensive understanding of the crack resistance behavior. Based on the digital image correlation method, notched semi-circular bending (SCB) fracture tests under different temperatures, loading rates and initial crack lengths were carried out. The cracking resistance index CRI and fracture toughness of asphalt concrete were calculated; Meanwhile, the crack resistance KR curves were analyzed. Research results indicate that compared with SCB samples tested at 0 degrees C similar to 20 degrees C, smaller CRI values under -10 degrees C are presented, indicating that asphalt concrete shows more brittle fracture behavior. The CRI values gradually decrease with the loading rate and are less affected by the initial crack length. The fracture toughness decreases with the temperature and initial crack length, and its values show an ascending tendency with the loading rate. The KR curves increase with crack propagation length, indicating that the crack resistance ability of asphalt concrete is improved during the crack evolution process.