| Fischer-Tropsch wax FT wax,as an asphalt modifier,can greatly improve the high-temperature performance of asphalt and significantly reduce the Brinell viscosity of asphalt.Of course,FT wax modified asphalt also has some shortcomings,such as poor crack resistance at low temperature.SBS modifier also has good modification effect on asphalt.SBS modified asphalt has excellent crack resistance at low temperature.SBS can be melted into asphalt under high-speed shear conditions,and can be mixed with other polymers for composite modification,so it can be combined with Fischer-Tropsch wax for composite modification.However,the storage stability of SBS modified asphalt is poor,and segregation will occur if the static time is too long.Based on the respective advantages of the two modifiers and the easy production of Fischer-Tropsch wax,this paper proposes to use FT and SBS to modify asphalt.Fischer-Tropsch wax is compatible with base asphalt,and the scheme of composite modification is established by orthogonal experiment.According to the three indexes of FT/SBS composite modified asphalt,Brinell viscosity and elastic recovery,the main influencing factors were analyzed,and the optimum preparation process was determined.FT/SBS composite modified asphalt was prepared.The formula of FT/SBS composite modified asphalt was optimized to compensate for the low temperature ductility of modified asphalt.The regular performance of composite modified asphalt varies with the content of FT and alkylbenzene.The physical properties of FT/SBS composite modified asphalt were evaluated by SHRP index.The rheological properties of modified asphalt at medium and high temperature and at low temperature were measured.Storage stability,short-term aging and thermal dispersion of FT/SBS composite modified asphalt.Pavement performance of FT/SBS composite modified mixture.The results show that FT can significantly improve the high temperature performance of asphalt,and has a good viscosity reduction effect.Good fluidity of FT modified asphalt is conducive to high temperature construction mixing.FT/SBS composite modified asphalt was prepared according to the optimum preparation process obtained by orthogonal experiment.WJB and FT can complement each other by FT and WJB content test.After adding FT and SBS,the high temperature performance of asphalt was significantly improved,and the temperature sensitivity ofasphalt at high temperature,moderate temperature and low temperature was significantly reduced.At low temperature,FT/SBS composite modified asphalt had good flexibility,but its stress dispersion ability became worse.Some cross-linking reactions between FT,SBS and matrix asphalt were possible.The addition of FT and SBS significantly improved the asphalt resistance.Chemical properties;FT/SBS has poor storage stability and is easy to segregate,and does not segregate after adding stabilizer.It can be seen from the thermal stage phase contrast microscope that the dispersion effect of FT/SBS modified asphalt is better and better with the increase of static thermal storage time,that is,its stability is improved.Finally,the pavement performance of FT/SBS composite modified asphalt mixture is studied.The mixture has good high temperature stability,excellent rutting resistance,good water damage resistance and strong fatigue resistance.FT has no adverse effect on low temperature performance of composite modified asphalt mixture. |
