Investigation on the Feasibility of Different Semicircular Bend Methods for Asphalt Concrete

Cracking of asphalt pavement is mostly caused by the mixed fracture of asphalt concrete. Determining a simple, repeatable, and accurate method is necessary for evaluating the fracture resistance of asphalt concrete. To explore the mixed fracture performance of asphalt concrete and determine the feasibility of different semicircular bend methods, the mixed fracture performances of asphalt concrete at medium and low temperatures were measured. The mixed fracture modes were realized through changing the position of the support and notch or changing the notch angle. After that, the crack propagating characteristics, crack initiation angle, and fracture toughness were analyzed. Results show that temperature has a significant impact on the fracture path, and crack initiation angle at low temperature follows the generalized maximum tangential stress (GMTS) theory. The measured fracture toughness ratios are lower than the theoretical value of GMTS criterion, but the established empirical model has higher accuracy. In the semicircular bend method, changing the positions of the support and notch is stable and repeatable. Therefore, this method may be preferred to evaluate the mixed fracture performance of asphalt concrete in the future.

Automated summary

This study explores the mixed fracture performance of asphalt concrete by changing the position of the support and notch or changing the notch angle. The measured fracture toughness ratios are lower than the theoretical value, but the empirical model has higher accuracy. The semicircular bend method with changed support and notch positions is stable and repeatable, which may be preferred for evaluating the mixed fracture performance of asphalt concrete in the future.