Reserch On The Viscoelastic Characteritistic And High Temperature Properties Based DMA Of Rubber Asphalt

Domestic and overseas index system is mainly based on common indexs, including the Brookfieldviscosity,the penetration, the softening point, etc. And the limitation of those index on evaluating rubberasphalt is known to all. In SHRP, the viscoelastic property of base asphalt got systematically studied, andalso on SBS modified asphalt. But it is still rarely studied in the viscoelastic property of rubber asphalt.Some research work aiming at high temperature rheology of rubber asphalt has been done in this paper:Firstly, starting with feasibility of the rubber asphalt DSR test, by sweeping various temperature ofrubber asphalt in different interstice between parallel plates, variability of parameters in different conditionsis studied, the test condition of rubber asphalt DSR is presented, which the variability can be controlledwithin5%when distance between parallel plate is2mm and stain is10%.Secondly, temperature sweep was adopted for different mesh number, different content (viscosity),different base asphalt and rubber asphalt. Data at58℃～82℃such as complex modulus, phase angel andcomplex viscosity were processed. The change law of morphology structure of rubber asphalt is analyzed.Rut factor and SBS improved rut factor are achieved, then analyzed on adaptability, and rut factor applyingto rubber asphalt is proposed.By frequency sweep test to kinds of rubber asphalt above, the data in different frequencies at60℃such as complex modulus, phase angel and complex viscosity is achieved, and storage modulus, lossmodulus and complex viscosity are fitted with master curve, then shift factors and material parameters C1、C2of different rubber asphalt are obtained; Cross model, Carreau model and the fitting master curve ZSVof rubber asphalt are calculated, combined with rubber asphalt ratio, Cross model and Carreau model ZSVare proposed for evaluation index of high temperature property.Repeat creep tests are performed with7kinds of rubber asphalts in different viscosity grades. Thestrain change of rubber asphalt under different stress at60℃is obtained, the creep deformationcharacteristics of rubber asphalt under different states of stress and viscosity are analyzed, ZSV of repeatcreep andG Vof viscosity stiffness modulus are calculated. Combined with viscosity grades of rubberasphalt and different base asphalt law, creep test ZSV is proposed as the evaluation index of hightemperature property.Then, relevant experimental studies are performed on the maininfluencefactors of regular hightemperature index of rubber asphalt, adaptability of high temperature property of rubber asphalt is analyzed,its viscosity property is analyzed in conjunction with modified mechanism of rubber asphalt. After mixdesign of3kinds of gradation and4kinds of viscosity grades,12kinds of rubber asphalt mixture areperformed by Hamburg wheel tracking test, high temperature property index of mixture such as strainamount, strain rate and slop in stable stage can be achieved. And combined with mixture gradation, theasphalt-aggregate ratio and rubber asphalt property, strain rate is proposed as the evaluation index of hightemperature property, strain amount and the slop in stable stage as the reference indexs.Finally, correlation analysis is performed on regular high temperature index and high temperaturerheology index of different rubber asphalt. The Brookfield viscosity, AR rut factor and ZSV of the Carreaumodel are proposed as the evaluation indexs of rubber asphalt’s high temperature property,softening point, Cross model, ZSV of repeat creep and viscosity stiffness modulus as the reference indexs.Correlation analysis is performed on high temperature property index of rubber asphalt and hightemperature index of mixture, strain rate is proposed as the evaluation index of rubber asphalt mixture’shigh temperature property, strain amount and the slop in stable stage as the reference indexs.