Evaluation of fracture and fatigue cracking characterization ability of nonstandardized semicircular-bending test for asphalt concrete

Reclaimed asphalt pavement (RAP) has been used recently in warm-mix asphalt (WMA) as a part of sustainable and green pavement design. The main issue of using high RAP content in WMA is associated cracking. To optimize the use of RAP in WMA and reduce life cycle costs, a robust tool of testing to control the quality of asphalt mixtures in terms of cracking is vital. Among the available tests, the semicircular-bending (SCB) test is regarded as simple but useful to characterize the cracking behavior of asphalt concrete. The test has been standardized in a number of standards for 150-mm-diameter samples. Recently, the authors investigated and proved that the SCB test on 100-mm-diameter samples produced acceptable repeatability compared with standardized samples based on experimental and numerical tests, providing an alternative choice for practitioners and researchers with the tools and equipment available to conduct the test. However, the characterization ability of cracking behavior, in particular the fracture and fatigue, of asphalt mixtures using this nonstandardized test has not been studied yet. Thus, this study was conducted to investigate the potential for characterization of cracking behavior of nonstandardized SCB testing for asphalt mixtures. Laboratory tests were conducted on different mixtures, including hot-mix asphalt, WMA, and WMA with added RAP. A four-point bending fatigue test was also performed to compare with results from the SCB test. The study found that the SCB test on nonstandard samples could be used to evaluate the cracking resistance of asphalt mixtures. It was also found that production temperatures, WMA technologies, RAP contents, notch lengths, and air voids considerably affected the cracking behavior of asphalt mixtures.