Cracking Resistance Characterization of Asphalt Concrete Containing Reclaimed Asphalt Pavement at Intermediate Temperatures

The cracking resistance of asphalt concrete (AC) that contains reclaimed asphalt pavement (RAP) was evaluated in this study with a fracture energy approach. Monotonic and cyclic semicircular bending (SCB) tests were performed with the digital image correlation to correlate crack length with fracture energy. Five types of AC that contained various RAP content (0%, 15%, 30%, 40%, 50%) were evaluated at two intermediate temperatures (15°C and 25°C). On the basis of the relationship between fracture energy and crack extension length, several performance indicators for cracking were proposed: fracture energy and crack initiation energy in monotonic and cyclic SCB tests, an energy cumulative rate in monotonic SCB tests, a fatigue accumulation index (FAI), a fracture energy index, and the slope of the crack steady propagation stage (SOCSP) in cyclic SCB tests. The effects of the RAP content on these indicators were investigated. It was observed from the test results that RAP reduced the fracture energy and crack initiation energy in the monotonic and the cyclic SCB tests. RAP led to a lower energy cumulative rate than an AC mix without RAP in the monotonic SCB tests. Similarly, the FAI and SOCSP values were found to decrease with an increase in RAP content in the cyclic SCB tests. These results indicated that, in general, the addition of RAP reduced the cracking resistance at intermediate temperatures.