Evaluation of degree of blending and its effect on performance of recycled hot-mix asphalt under different preheating conditions

This research comprehensively explored the function of preheating temperature and quantified the contribution of degree of blending (DoB) to performance of recycled hot -mix asphalt (HMAs). Five groups were designed, including no blending group, full blending group, and three experimental groups at preheating temperatures of 60,110, and 160 degrees C. It can be found that the preheating temperature played a positive impact on DoB and performance of recycled HMAs. As the preheating temperature increased by 50 degrees C, about 0.13%-0.2% of reclaimed asphalt binder can be additionally activated, and the tensile strength ratio, shear strength, and fracture energy of recycled HMAs can improve by around 6%-8%, 0.07-0.15 MPa, and 304.2-335.4 J<middle dot>m2, respectively. Moreover, the results showed that the performance of recycled mixes designed at preheating temperature of 60 degrees C was close to that of no blending group, while the mixes designed at a preheating temperature of 160 degrees C can reach to those of full blending group.