Evaluation Of Blending Degree Between RAP Binder And Virgin Binder Based On Stage Extraction

With the global climate and energy issues,the government pay great importance on sustainable development and environment protection,and asphalt mixture especially warm mix asphalt containing RAP(Reclaimed Asphalt Pavement)is becoming popular in highway construction.Also,the blending degree between RAP binder and virgin binder have great influence on the performance of asphalt mixture.At present,the understanding of the reclaimed asphalt mixture in the road engineering field is limited to the macroscopic level and the explanation of the mechanism is lacking.Therefore,it is meaningful to study the blending degree between RAP and virgin binder in this paper.Based on the stage extraction,different layers of asphalt enfolding RAP are extracted and tested with frequency sweep and fluorescence microscopy to compare the influence of temperature,RAP content and warm mix additive.MSCR(multiple stress creep recovery),LAS(linear amplitude sweep),and surface energy evaluation are tested with reclaimed asphalt,to figure out the influence of RAP binder.The main conclusions and innovations are as follows:1.The result of frequency sweep with extracted binder shows that virgin binder can softer the RAP binder and the reclaimed asphalt is getting harder from outer layer to inner layer.2.The fluorescence microscopy informs that the mean gray value can calculate the content of RAP binder so as to evaluate the ratio of RAP and virgin binder in different layers of reclaimed asphalt.3.A new method to evaluate the blending degree between RAP binder and virgin binder is raised based on the calculation of RAP content in reclaim asphalt.4.The blending degree of asphalt mixture is higher with lower RAP content and higher temperature and the blending degree of hot mix asphalt containing RAP is higher than warm mix asphalt containing RAP.The blending degree is different with different warm mix additives.The blending degree of warm mix asphalt with good additives is closer to hot mix asphalt.5.The RAP content has great effect on the performance of reclaimed asphalt.RAP binder can improve the rutting performance of reclaimed asphalt but has negative effects on water damage on mixtures.With the increase of RAP content in reclaimed asphalt,the fatigue resistance tend to climb up and the decline...