The Experimental Study On Old Asphalt’s Regeneration Behavior In Central Plant Hot Recycling

Along with our country’s highway which built in early time has gradually enter the period of medium maintenance or major overhaul,the related project like pavement’s repair and maintenance or reconstruction and extension project would generate a lots of RAP materials.Central plant hot recycling is a kind of effective way to consume the RAP materials which has been greatly received by our nation or world.In practice,the RAP materials would be crushed at first,then it would recovery it’s properties by mixed with new asphalt and new aggregate.In reality,the process of regeneration is consist of two major parts.The one is old aggregate’s regeneration,the other one is old asphalt’s regeneration.Obviously,the latter one has a more significant meaning.In the process of mixing,there will have a blending process between the new and old asphalt.But the asphalt’s components are sophisticated which can be a obstacle to observe the process of mixing.That’s the reason why there are few related observing material.Under this background,this article designed some related experiment to research the blending process between new and old asphalt during the process of Plant-mix heat recycle technology.According to the practical process,the whole process can be divided into three parts.The first one is old asphalt’s transfer characteristic to new aggregate’s surface.The second one is new asphalt diffuses into old asphalt.The last one is the blending between new and old asphalt.As for the old asphalt’s transfer characteristic,it proposed the ratio of old asphalt’s effective regeneration which based on asphalt mixture’s mixing experiment.Comparing the effect by change the stirring rate,RAP’s preheating temperature,rejuvenator’s amount,then proposed some measures which can improve the ratio of old asphalt’s effective regeneration.As for the diffusion process,the text designed a method which based on penetration to evaluate the diffusion process.It also research the new asphalt’s diffusion by change the conditions like asphalt’s type,asphalt’s aging degree,storage time and temperature.In the mean time,it also adopt DSR to research the asphalt’s diffusion when the asphalt exist as a thin film.When it comes to the blending process,it also use the penetration experiment to evaluate the mixing between new and old asphalt under the condition of different aging degree,different amount and different stirring time.Still use the DSR to evaluate the asphalt’s high temperature property under 60℃ by changing blending condition.