Research On Influence Of New Asphalt Mixture On Hot In–place Recycling Performance And RAP Grading Fluctuation Range

With China’s high-grade asphalt roads ushered in the peak maintenance period,hot in–place recycling technology has become more and more widely used at home and abroad due to its characteristics of saving non-renewable materials and processing asphalt mixtures pavement.In this paper,the effect of new asphalt mixture addition on the performance of recycled asphalt mixture during hot in–place recycling and the optimized sampling mix ratio design under the fluctuation of RAP material gradation are studied,and the control requirements for new new asphalt mixture addition are proposed based on field engineering and hot in–place recycling equipment..First,after analyzing the asphalt content,aging asphalt properties and gradation of the RAP material of Shizhong and Chengyu highway,the recycling agent and SBS I-D modified asphalt are mixed for aging asphalt regeneration.Determine the optimum asphalt aggregate ratio and mixing temperature and time of the reclaimed material,and study the effect of the new asphalt mixture mixing rate and temperature on the performance of the reclaimed material.The results show that the new asphalt mixture mixing rate has many effects on the regeneration effect.Improve the road performance of recycled materials;the temperature of new asphalt mixture has a significant impact on the water stability of recycled materials.Secondly,change the RAP material 0.075 mm,2.36 mm,4.75 mm sieve pass rate,study the RAP material performance changes,so as to determine the allowable fluctuation range of RAP material gradation in hot in–place recycling technology process.Orthogonal test was designed for the three screens with the same passing rate.The splitting strength ratio and dynamic stability data were used to establish a BP neural network prediction model.The errors of the simulation results were about 6% and 12%,respectively.Paragraph division sampling and re-ratio design have certain reference value.Finally,relying on the Nanfu highway hot in–place recycling project and the Wirtgen regeneration unit,it solved the control of spraying of recycling regenerant,the amount of new asphalt mixture added,the management of new asphalt mixture transportation and the conveying speed of the conveyor belt in the compounding machine problem.And the quality of the road surface after thermal regeneration maintenance is measured,and its indicators meet the requirements of the specification.The research conclusion of the thesis is helpful to improve the Technology guideline for Hot in–place recycling Construction of Asphalt Pavement and the application effect of the technology.