Abstract:In order to study the influence of mixing effect of old and new asphalts at the interface of recycled asphalt mixture on the fatigue properties of mixture under same grading and different mixing factors, and based on the infrared spectroscopy, the qualitative problem of "partial mixing" of new and old asphalt during the regeneration process is turned to quantitative problem, and a quantitative evaluation scheme of the mixing effect of recycled asphalt mixture is established, and the relationship between the mixing effect of the new and old asphalts at the interface and the fatigue life of the recycled materials under the factors of different RAP content, mixing temperature and dry mixing time is studied, and then the mixing scheme is optimized. The results show that under the different mixing factors, the fatigue performance of the mixture changes with the mixing effect change of new and old asphalts at the interface. The best mixing scheme is 40% RAP content, 165℃ mixing temperature and 90 s dry mixing time.