Research On The Application Of Hot Recycled Asphalt Mixture In Fujin Expressway

With the gradual completion of the domestic road network,asphalt pavement accounts for more than 90% of high-grade highways.In the process of long-term service,the asphalt pavement is affected by the coupling of factors such as load and environment,and its road performance will be attenuated to varying degrees,which will affect driving safety in serious cases.In order to conserve resources and at the same time make the most of pavement materials,recycling technology has emerged.In order to further improve the popularization and application of plant hot recycling technology in high-grade highways,the road performance of plant hot recycled asphalt mixture was studied,the mixing ratio of plant hot recycling modified asphalt mixture was designed,and it was applied to the maintenance project of Fujin Expressway,so as to accumulate experience for the engineering application of plant hot recycling modified asphalt maintenance technology.First of all,the overall situation of the Fujin Expressway was introduced,and the road surface was comprehensively tested.The main line carriageway and passing lane were milled 2.5cm,the hard shoulder milled 2.5cm or 0.5cm,and then the road surface disease was treated,and the maintenance plan of AC-16 plant hot recycled modified asphalt mixture was added as a whole.Secondly,the RAP pretreatment process and requirements are studied.It is found that the direct screening operation process is simple,and the multi-stage joint screening operation can ensure the screening effect.By comparing the milling-double-roll-multi-stage combined screening process,the counter-direct screening process,and the counter-rotor centrifugation-multi-stage combined screening process,it is found that the RAP pretreatment effect of the last process combination is the best.The SBS modified RAP pretreatment process crushing equipment combination can be added to the rotor centrifugal crusher and use multi-stage combined screening operation.Then,with reference to the graded design of AC-16,the mix ratio of recycled asphalt mixture with different amounts of RAP was determined,and the optimal asphalt content was determined by Marshall test.The synthetic grading of four different RAP mixtures can be maintained within the required grading range of AC-16,and the synthetic grading of recycled asphalt mixtures is well designed to meet the specifications.Through the indoor test of the road performance of recycled asphalt mixture with different RAP content,the improvement effect was analyzed.Finally,the recycled asphalt mixture was applied to the Fujin Expressway to study the key technologies of pavement construction.According to the design results of the target mix ratio,the production mix ratio gradation design was carried out,and the Marshall test was carried out according to the design results of the previous article,and the optimal amount of new asphalt for the production mix ratio was determined to be 4.7%,and a series of verifications including indoor test,appearance inspection and water permeability test were carried out for the recycled asphalt mixture prepared on site.The test results show that the recycled asphalt mixture meets the use standards and the performance is improved.