Design And Performance Of Ultra-viscosity OGFC Wearing Layer Based On High Viscositc Asphalt

OGFC ultra-thin wear layer is a drainage wearing layer.Due to its excellent drainage,skid-resistance,noise reduction,etc.,increasing attention has been paid.However,problems such as ravelling and peeling resulting fromits high voids volume and small amount of asphalt often occour.It is necessary to select high-viscositic asphalt with excellent performance to serve as a binder.At present,imported hi gh-viscositic asphalt is expensive,and most of the high-viscositic asphalt independently developed in China have disadvantages such as relatively lower viscosity and unstable quality.In this paper,multi-walled carbon nanotubes,waste tire rubber powder and SBS were used to produce high-viscositic asphalt in the labortary.The basic properties and modification mechanism were studied.On this basis,the mix proportion designing method of ultra-thin OGFC wearing layer was carried out.The road performance,interlaminar shear performance,construction technology and economy were analyzed.The main research contents and conclusions include:(1)SBS,waste tire rubber powder,carbon nanotubes and a stabilizer were selected as modifiers.The optimum contens of each ingredients of the high viscositic asphalt was determined by analyzing single factor test and orthogonal test indexes such as penetration,softening point,ductility,dynamic viscosity at 60?.Additionaly,DSR,BBR,SEM and IR tests were carried out.The results show that under the optimal formulation,i.e.,5%SBS,15%rubber powder,and 0.8%multi-wall carbon nanotubes,the softening point,5? ductility and 60? dynamic viscosity was 87.6?,28.4cm,201579.1 Pa-s,respectively.The penetration at 25? was 4mm,the PG grade reached PG88-28,and it indicated that the addition of multi-walled carbon nanotubes had a reinforcing effect on polymer modified asphalt;(2)OGFC-10 and OGFC-13 were selected to design ultra-thin OGFC wearing layer,and the mix proportion design,road performance and shear performance were conducted.The results showed that the optimum asphalt content of OGFC-10 and OGFC-13 was 4.85%and 4.95%,respectively.The dynamic stability,low temperature failure bending strain and the structural depth was higher than 3000 times/mm,2500?? and 1mm,respectively.The pendulum value was greater than 45BPN,the immersion residual stability and the freeze-thaw split test strength were higher than 80%.The optimum SBS modified emulsified asphalt amount was 0.8 kg/m2 at 20? and 40? and the optimum spreading amount at 60 ? was 0.6 kg/m2.At this time,the shear strength peaked.And OGFC-10 gradation was superior to OGFC-13;(3)Analysis and research on construction technology and economy of OGFC-10 was made.The results showed that construction temperature should be carefully controlled.The equivalent annual cost EAC was 3.5,indicating favorable economic benefit could be obtained.