Evaluation of the effect of aging on the long-term performance of warm mix asphalt (WMA) containing high percentage of reclaimed asphalt pavement (RAP) based on the results of semicircular bending (SCB) test at intermediate temperature

With regards to the increase in stiffness for the asphalt mixture containing RAP, the improvement of rutting is predictable, but with increasing aging level and increasing stiffness in mixtures containing high percentages of RAP, problems such as cracking at low and intermediate temperatures is formed in the long-term. In this study, the long-term fracture performance of WMA mixtures containing high percentage of RAP at 250c was evaluated using a SCB test. To conduct the research, different amounts of RAP (0, 50, 75, and 100%), a rejuvenator, Zycotherm as WMA additive and 85/100 asphalt binder were used. To apply different levels of aging, the samples were kept in the oven for 3, 5, 7 and 9 days at 850 C. The results showed that with increasing the amount of RAP and the aging level of the samples, the Pcr and the KIC increased, but the U decreased. Also, in order to compare the long-term performance of asphalt mixtures containing different percentages of RAP, the area under the Jc - aging is determined and it was concluded that in the long-term, samples without RAP show 8, 34, and 52% more resistance to cracks than samples containing 50, 75, and 100% RAP.