Study On Optimization Design And Application Of Thermally Recycled Asphalt Pavement Material Composition

Accurate evaluation of the ageing degree of old bitumen in reclaimed asphalt pavement(RAP)is an extremely important part of the thermal regeneration process,and is also the basis for the selection of the mixture regeneration method and the design of the regeneration ratio.This article aims at the deficiency of the method of extracting and recovering the asphalt by the rotary evaporator method in the existing specification,analyzes the reasons and proposes improvement measures,eliminates the influence of residual ore and residual trichloroethylene,and accurately recovers the asphalt in RAP.Because of the blending of RAP,the hot-recycled asphalt mixture cannot be accurately measured by the vacuum method or the calculation method to determine the maximum theoretical relative density.In this paper,by analyzing the causes of the maximum theoretical relative density of the hot regenerative mixture,the asphalt impregnation method was used for the determination,and the suitability of the RAP and the hot regenerative mixture was evaluated by two methods.After the asphalt pavement has been used for a long period of time,the asphalt will inevitably age and the viscosity will increase,causing the asphalt pavement to lose some of its original functions.RAP is still in the form of micelles due to the binding effect of aged asphalt,and the fine aggregates are wrapped around the coarse aggregates.In this paper,by designing a test method for determining the movement of old mineral particles in RAP during thermal regeneration,the influencing factors affecting the migration of old minerals in RAP are analyzed,and experiments are designed to study the above factors for old mines with different particle sizes.The influence of the migration movement of the material particles,and the optimization method of the migration rules of the materials was proposed.Based on the Shandong Provincial Transportation Science and Technology Project,“Research on Key Technologies for Long-term Performance and Application of Thermally Recycled Asphalt Pavements”,optimized design of thermal recycled asphalt pavement material composition was carried out.Taking SMA-13 as an example,the RAP ratio,the amount of regenerant additives,and mixing were determined.The hot recycled asphalt mixture is tested on the mix design.The indicators meet the specifications and the road performance is good.Combining with the practical engineering paving test section,the fatigue performance,anti-rutting performance and surface skid resistance of the asphalt pavement are tested through the accelerated loading test.Performance decay rate,compared with ordinary asphalt pavement,no obvious differences in the indicators,stable performance.