Experimental study of high modulus asphalt mixture containing reclaimed asphalt pavement

Abstract

This paper examines performance of high modulus asphalt mixture containing reclaimed asphalt pavement (RAP). Low penetration grade asphalt binder #30 was used to produce high modulus asphalt mixture containing RAP. Marshall mix design method was used to prepare specimen and EME (Enrobé à Module Élevé) method was incorporated. To address the variance of RAP gradation and poor bonding between stiff virgin binder and aged binder, a modified regeneration method was proposed in this study and was compared with traditional method. Performance of the mixture was examined with lab tests including Marshall stability and flow test, dynamic modulus test, bending test, Marshall immersion test and modified Lottman test. The results indicated that modified method produced more compacted, more stable mixture than traditional method, while low-temperature performance is still below standard. Specimens with different RAP content were prepared and tested to evaluate the effect of RAP content. It was found that 40% RAP produced optimal mixture in terms of dynamic modulus values and moisture damage susceptibility, while low-temperature performance is insensitive to RAP content. Scanning Electron Microscope (SEM) test was conducted to evaluate bonding between binder and aggregate from the micro structural perspective. The results support that modified method improves the bonding between virgin binder and RAP as well as virgin aggregate.