Full range I/II fracture behavior of asphalt mixtures containing RAP and rejuvenating agent using two different 3-point bend type configurations

In this study, a new test configuration was used to investigate the full range of mixed-mode I/II fracture behavior of asphalt mixtures using a Short Beam Bending (SBB) specimen with a vertical edge crack, which was subjected to an asymmetric three-point bending load. To evaluate the capabilities and assess the characteristics of this new specimen, the results of experiments were compared to Semi-Circular Bending (SCB) specimens. The materials used in this study were Stone Mastic Asphalt (SMA) mixtures containing various Reclaimed Asphalt Pavement (RAP) contents (0%, 30%, and 50%) with or without a rejuvenating agent additive. Results showed that pure Mode-I and pure mode-II fracture toughness values obtained from the SBB specimen were about 15% lower than fracture toughness obtained from the SCB specimens. Results also indicated that the addition of RAP materials into asphalt mixtures was improve the fracture toughness and fracture energy of asphalt mixtures. It can be inferred from the outcomes that the addition of 30% and 50% of RAP (with a rejuvenating agent) in asphalt mixtures increased the fracture toughness by roughly 20% and 30% in pure mode I and 15% and 25% in pure mode II, respectively. Besides, the rejuvenating agent also increased the fracture parameters values of RAPcontained asphalt mixtures in both sample types by an average of 10%. Moreover, a significant correlation between the fracture parameters of SCB and SBB specimens was observed.