Research On Micro-mechanism And Property Test Of The Central Plant Hot Recycling Asphalt Mixture At High RAP Proportion

For the past few years, as China emphasised the development of highway industry, themaintenance and transform engineering of highway increased gradually. Every year,160millions of tons RAP has been generated by the highway maintenance milling and planeoperation. It is land occupied, environmental polluted, ecological destroyed and resourcewasted if the160millions of tons RAP has been discarded. Providing that this entire amountof RAP could be recycled and reused,20billion could be preserved as direct material funds.Research on the reborn of RAP possesses economic, social and environmental effects. Themixed status of virgin and old asphalt within the hot recycling asphalt mixture is currently stillin the dark. Especially the mixed status of virgin and old asphalt within the hot recyclingasphalt mixture at high RAPproportion making significant effect onrecycling asphalt mixturein terms of its water stability, low temperature anti-crackingperformance and fatigue failure.To improve the property of recycling asphalt mixture and promote use ratio of RAP, thispaper adopt micro-experiment and property experiment to discover the status of asphaltmastic within recycling asphalt mixture. As the complicationof distinguish virgin asphalt andold asphalt, seeking a credible tracer material to sign the virgin asphalt, mixed with recyclingasphalt mixture, has been an appropriate approach for identifying the old asphalt within therecycling asphalt mixture. First, primarily selected some types of trace materials likenano-ZnO, melamine and Sb2O3. Then, through SEM experiment and trace materials/asphaltphysical propertyexperiment, it is able to make sure the type and amount of tracer material (5%Melamine and4%2#nano-ZnO); stir method (colloid mill and high-speed shear method);sample preparation method (thick glass) and observe method (fracture surface). Adding5%Melamine/sphalt binder into recycling asphalt mixture and adopting SEM experiment todetect Melamine existing in asphalt mastic which is on the surface of aggregate in recyclingasphalt mixture. Compare the asphalt mastic of RAP, common asphalt mixture and recyclingasphalt mixture, it is make sure the existing rang of Melamine in the asphalt mastic ofrecycling asphalt mixture. The primary experimental results revealed that the valid range of blendingbetween virgin asphalt withold asphalt on the surface of RAP is53%and75%. Theexperiment of property of recycling asphalt mixture is that a mix design for AC-13recyclingasphalt mixture in terms of two RAP proportions (40%and60%) and is based on theassumption that when the valid asphalt ratio is70%;80%;90%and100%respectively. Thepavement performance experimental results indicate that when the valid asphalt ratio is onefrom experiment between70%and90%, RAP performs better in terms of Marshallperformance, high temperature stability, low temperature anti-cracking performance, waterstability and flexuraldeformation property.Take Guang-Hui freeway as a base project, gradually promoting the application ofCentral Plant Hot recycling technology to the top, middle and under surface course of main,overtaking lane. Improving the blending proportion of RAP and widely using RAP in realengineering. Improving economic efficiency of pavement construction. The examinationalresult of surface course of test section revealed that every indicator accords with quality andrelevant technological standard and perform with good property.That is established a basis forfurther increase the blending proportionof RAP.