Effects of Loading Rate and Temperature on Cracking Resistance Characteristics of Asphalt Mixtures Using Nonnotched Semicircular Bending Tests

In this study, the effects of loading rate and temperature on the cracking resistance of asphalt mixtures under static loading were examined by a nonnotched, semicircle bending test. Twenty-four test conditions combined by eight loading rates (0.1, 0.75, 3, 7.5, 15, 30, 50, and 80 mm/min) and three temperatures (−10°C, 0°C, and 15°C) were selected to be conducted using one stone matrix asphalt mixture. Five cracking parameters, namely, peak force (Fmax), peak displacement (Dp), work of before-cracking (Wc), cracking failure displacement (Dcf), and work of cracking failure (Wcf), were proposed in order to evaluate the cracking resistance of asphalt mixtures. According to the results of this study, the cracking failure mode of asphalt mixtures can be divided into three conditions: brittle cracking, flexible damage, and fall in between. For the test condition of a higher loading rate and lower temperature, the cracking failure mode would be closer to brittle cracking. Both loading rate and temperature influence the test results of all cracking parameters in different ways. According to the statistical analysis, peak force is sensitive to loading rate, and the displacement and energy parameters are sensitive to temperature variation.