北京地区高比例RAP热再生沥青混合料路用性能演化及合理掺量研究OA

In order to clarify the critical dosage,road performance evolution law and control scheme of high proportion reclaimed asphalt pavement(RAP)of hot recycled asphalt mixture in Beijing,SMA-13 RAP with 12 years of service on high-grade roads in Beijing was taken as the research object.Hot recycled asphalt mixture with 0％to 50％RAP dosages was designed,and a series of tests were conducted on volume properties,high temperature stability,water stability,low temperature crack resistance and fatigue performance.Combined with the micro performance of the binder and the fusion characteristics of new and old asphalt,low temperature safety factor,fatigue safety factor,and comprehensive judgment index were introduced to construct a quantitative criterion for critical dosage.The control effect of aromatic oil rejuvenator(R1)and composite rejuvenator(R2)in the critical dosage range was explored.The results showed that increasing of the RAP content continuously improved the high temperature stability of the mix-ture,while the water stability showed a slow deterioration trend but still met the specification requirements.Low temperature crack resistance and fatigue performance were the main control indicators for determining the critical content;The critical performance transition range was between 30％and 40％.Within this range,the effective as-phalt film thickness of the mixture dropped below 10 μm,and the low-temperature bending tensile strain and fa-tigue life accelerated deterioration.The stiffness of the binder increased sharply,the viscoelasticity significantly weakened,and the aging degree rapidly intensified.The optimal dosage of rejuvenator for improving the performance of the critical dosage range mixture was 5％,R1 had a better control effect than R2,which can effectively improve the fusion effect of new and old asphalt,but can't completely offset the performance degradation caused by high dosage RAP.Based on quantitative criteria and the climate,transportation,and engineering characteristics of Beijing,the critical RAP content threshold for SMA-13 hot recycled asphalt mixture in Beijing was determined to be 30％,and three content intervals were divided:≤30％recommended for direct application,30％～40％critical regulation,and ≥40％prohibited for direct application.The corresponding engineering application requirements and regulation schemes for each interval were proposed.The research results provide scientific basis and technical support for the precise and green application of high proportion RAP thermal regeneration technology in road maintenance projects in Beijing.