Research On The Structure And Properties Of Asphalt Modified With PU/active Filler

At present,asphalt modified by SBS is mainly acted as the binder for asphalt pavement.It is just simple physical blending between SBS and asphalt,which limits its application in engineering because of lack of stability in high temperature.Polyurethane(PU)has excellent resistance to weather and wear.In the subject,castor oil and pure MDI are used to synthesize polyurethane prepolymer with different NCO content,which are added to asphalt as modifier to explore its modification effect.On the basis,the modified asphalt sample are prepared with the method of combination of organic and inorganic modifier.Through analysis of softening point,viscosity,needle penetration,segregation test,microstructure observation,FTIR and rheological property,the effect of halloysite nanoparticles(HNTs),methylcellulose(MC),ethyecellulose(EC)and PU additive amount on asphalt structure and properties are explored.The test results show that the modification effect is related to both the content of free NCO group and PU molecular structure.When the additive amount of PU with 20.71% NCO is 2%,the modification effect is best.PU has good dispersibility in asphalt and good compatibility with asphalt.When the additive amount of PU is 2%,the addition of HNTs is more than 2%,the addition of MC is no more than 1.5%,the addition of EC exceeds 1.5%,the modified asphalt has better stability of high temperature.With the increase of the amount of HNTs,its dispersion is worse and worse,while MC and EC have good dispersibility.Active filler is beneficial to the rheological property of asphalt.