Development And Performance Evaluation Of Warm Modified Recycling Of RAP Containing Conventional Bitumen

The traditional hot recycling technology can recycle the reclaimed Asphalt Pavement(RAP)into asphalt mixture,but the technology has the following issues,the low temperature crack resistance and water stability of recycled asphalt mixture are poor leads to the old material content is low(?20%).Based on the above issues,the Warm Modified Recycling technology for RAP containing conventional bitumen was developed in this paper.First of all,the aging of asphalt with different degrees is simulated by indoor short-term aging(RTFOT)and long-term aging(PAV)in this paper,and the aging asphalt in the waste asphalt mixture in the actual pavement milling is recycled.By evaluating the performance index of aged asphalt,it was found that the asphalt penetration and ductility decreased with the increase of aging time,and the softening point and viscosity increased,and the aged asphalt became hardened,brittle and rheological properties decreased.At the same time,two kinds of indoor simulated aging and the actual aging of the pavement were found,based on the RTFOT method,a large amount of asphalt was prepared,and the raw materials were provided for the follow-up experiment.Then,development principles were put forward based on the asphalt aging mechanism in this paper.Raw materials of compound rejuvenating agent each component was primarily elected based on the development principles and regeneration target.Through the orthogonal design method and analysis,the formulation of compound warm mix rejuvenating agent was confirmed and optimum dosage of compound rejuvenating agent was decided by the degree of asphalt aging and the regeneration target.Compound warm mix rejuvenating agent not only can recover the performance of the waste conventional asphalt and make it meet the SBS modified asphalt I-C standards,but also improve the anti-strip performance.In the end,valuated the road performance of warm modified recycling asphalt mixture with different RAP content(30%,45% and 60%)was evaluated in this paper.It was found that with the increase of RAP content,the high temperature performance of warm modified recycling asphalt mixture was enhanced,but its low temperature,water stability and fatigue properties showed a decreasing trend.Compared with SBS modified asphalt mixture,it was found that when the content of RAP was 30%,the road performance of the modified asphalt mixture was basically the same.it was found that when the content of RAP was 45%,the road performance of the modified asphalt mixture was decreased,but they could meet the requirements.When the content of RAP was 60%,the low temperature performance and water stability of the warm modified recycling asphalt mixture couldn't meet the requirements.