Research On The Application Of The Recycled Asphalt Mixture With The Warm Mix Asphalt Technology Containing High RAP Content

Currently,the reclaimed asphalt pavement(RAP)is prone to age in recycling due to the high temperature.Since the production temperature can be declined by the warm mix asphalt(WMA)technology,which has become a research point.The WMA technology is always used in the recycled asphalt mixture with low content RAP(lower than 30%).Moreover,the investigation of the recycled asphalt mixture with WMA technology containing the high content RAP is limited,especially in the application and construction technology.Hence,this thesis studied the recycled asphalt mixture with WMA technology containing high content RAP(30%and 60%),supplying the theoretical basis of its application.Firstly,the basic properties of raw materials were tested and the three major indices test were carried out.The ductility and penetration of the recycled asphalt with WMA were improved while the high-temperature performance was decreased with the increase of warm mix regenerant.The type of warm mix regenerant and the optimum content of 10%by the asphalt mass were determined through the indices variation and economy cost.Secondly,the variability of the RAP was investigated.The result showed that the variability of the RAP was low,which meet the application requirement.The optimum mixing time for the preparation process was determined to be 60s,the optimum mixing temperature to be 128℃～136℃ and the compaction temperature to be 122℃～128℃ by the equal volume method.A comparison of the equal volume method with the equal temperature method shows that the equal method is more intuitive in the mixing and compaction stages to reflect the actual forming of the warm mix.The optimum asphalt content was determined by the Marshall design method.The pavement performance of the recycled asphalt mixture with WMA technology containing high content RAP were verified.then,the construction technology was studied.the variability of RAP was declined effectively by these method such as layered milling,classified storing,and crushed sieving.In the construction process,the milling and paving speeds were required 3-4m/min and 4m/min.Moreover,the speeds of first,second,and third compaction was required 2km/h、3.5km/h and 4km/h.The benefit analysis shows that the cost and energy were saved 25.3%and 13.7%per ton compared with the hot mix asphalt mixtures.In addition,the emission of harmful gases can be reduced by more than 79%.In additon,the EAC parameter of warm mix asphalt mixture with 30%RAP was lowest,which indicates this asphat mixture possess a good economy value.In short,this thesis not only investigates the conduction technology,the basic properties of raw materials,mix proportion design,and road performance of the recycled asphalt mixture with WMA technology containing high content RAP,but also proposes the construction requirement and economic analysis.It is supplying guidance of the recycled asphalt mixture with WMA technology containing high content RAP on the real engineering application.