Fracture behavior of asphalt pavement with cracked base course under low temperature

Low temperature cracking is a distress mode of particular concern for asphalt pavements in cold regions. Traditionally, research regarding pavement low temperature cracking has mainly focused on surface-initiated transverse cracking. However, cracks in underlying base course can reflect through asphalt pavement layers under thermal stresses. In this study, a new approach (refined mesh) to describe crack tip stress singularity was introduced to study the low temperature cracking behavior with cracked base course using the Finite Element Method (FEM). Fracture toughness of one asphalt mixture that is commonly used in the northern part of China was measured under three temperatures, 0 °C, -10°C and -20°C. Sensitivity analysis was performed on stress intensity factor at crack tip to determine critical factors on surface course cracking behavior. Meanwhile, cracking behavior of surface course was evaluated by comparison between stress intensity factors at crack tip and mixture fracture toughness. Results indicated that surface course thickness has little effect on stress intensity factor at crack tip, and that the crack propagation in asphalt pavement surface course can be divided into two stages, stable and unstable. © Chinese Society of Pavement Engineering.