Design And Performance Experimental Research Of Hot Recycled Asphalt Mixture

Asphalt pavement will gradually generate cracks and pits, even occurring severe fracture. But if the destructive pavements were maintenance timely, they can be reused and extend the life of the road through recycling methods. Asphalt pavement recycling technology has significant ecological benefits. The re-use of RAP will save a lot of raw materials, solving shortage of the resources. Material savings also reduces the economic costs and brings better social benefits. Asphalt pavement recycling technology has got more and more attention, so it becomes a research hotspot in asphalt pavement.Based on the results that people have ever examinated, this paper researches the mechanisms of asphalt aging and regenerative mechanism by the current research both at home and abroad. In order to improve the utilization of waste asphalt, the blending methods and contents of RAP of hot recycled asphalt mixture were discussed. On this basis, using rutting test and freeze-thaw splitting test to further research the impact of different RAP contents on hot recycled asphalt mixture’s performance, which includes high temperature stability and resisting water damage ability.Firstly, this study summarized the hot recycled asphalt mixture’s home and abroad research background, analyzing the mechanisms of asphalt aging and regenerative, and concluding the technical approach.Studied the old asphalt and aggregate performance and analyze the characteristics of the old material gradation. With the increase in the aggregate size of the RAP, the asphalt content showed a downward trend.When designed the recycled asphalt mixture’s Mix, focused on the blending way RAP. Used the gray correlation analysis on the dynamic stability and Marshall eigenvalues of recycled asphalt mixture, the main factor of mixture’s rutting resistance was Marshall modulus. With the coefficient of variation of Marshall modulus, choosing1#blending method, which has less proportion of4.75mm-9.5mm aggregate and more proportion of9.5mm～13.2mm aggregate.Finally, verified the high temperature performance and water stability of asphalt mixture. The incorporation of RAP can significantly improve the performance of recycled asphalt mixture’s high temperature performance. With the increase of old material content, the dynamic stability of the mix and freeze-thaw splitting strength ratio emerged first increased and then decreased. Within appropriate RAP content’s range, the incorporation of the old material in favor of recycled asphalt mixture water stability, but needed to control the maximum content of RAP. Finally, study concluded the construction technology of central plant hot recycling asphalt pavement, giving proposals about heating temperature control of old and new aggregate.