Effects of moisture contents, fracture modes, and temperatures on fracture toughness and crack distribution of asphalt concrete at low-temperature

Low-temperature cracking of asphalt pavements is a major issue in highway construction. The deterioration of fracture resistance in asphalt pavements is accelerated by traffic loads when water infiltrates the cracks. However, previous studies have largely overlooked the effects of moisture content on the low-temperature cracking behaviour of asphalt concrete, particularly under different fracture modes. To address this gap, we investigated the fracture toughness and crack distribution of asphalt concrete using semicircular bending tests under five low-temperature conditions (-10 °C, −5 °C, 0 °C, 5 °C, and 10 °C), five moisture contents (0 %, 25 %, 50 %, 75 %, and 100 %), three fracture modes (mode I, mode II, and mixed mode I&II), and two types of asphalt binders (base asphalt binder and styrene–butadiene–styrene modified asphalt binder).