Study On The Effect Of Aging On The Performance Of Poly Phosphoric Acid Modified Asphalt

The pavement performance of asphalt pavement has become the most important type of road construction.Due to the impact of climate change,the asphalt pavement is easy to destroy,the ordinary asphalt has been difficult to meet the requirements of road traffic conditions,The researchers have found that adding modifier can improve the performance of asphalt pavement,so the research of modified asphalt has gradually become the focus of research.In this paper,the use of poly phosphoric acid(PPA)modified asphalt,PPA composite modified asphalt,SBS modified asphalt as the research object,based on rheology theory,study of PPA modified asphalt aging before and after the micro to macro.The characteristics of high temperature and low temperature were compared and studied,to provide basis for the application of PPA modified asphalt.Atomic force microscopy(AFM)analysis of PPA modified asphalt shows that the addition of PPA modifier improves the interaction between asphaltene and other components in the matrix asphalt and reduces the difference in properties between asphaltene and surrounding asphalt.The increase in the number of PPA modified asphalt hardness increases,PPA modified asphalt to enhance the high-temperature anti-rutting ability.The addition of PPA played a similar role as stabilizer for SBS modified asphalt,reducing the interfacial energy between matrix asphalt and polymer molecules,preventing the aggregation of polymer molecules and promoting the dispersion of polymer molecular phase.With the increase of PPA content,PPA composite modified asphalt formed a network structure,which enhanced the crosslinking effect of asphalt and polymer molecules and improved the storage stability of asphalt.The anti-aging properties of modified asphalt were analyzed by the residual penetration ratio,the softening point change and the retention retention rate obtained by the penetration degree,the softening point and the ductility test.At the same time,using the penetration index,viscosity index and viscosity index to evaluate the temperature performance of modified asphalt,The results show that the addition of PPA reduces the temperature sensitivity of modified asphalt,has good temperature stability,and improves the anti-aging ability of modified asphalt.With the increase of PPA content,the aging resistance is better.The rheological properties of the modified asphalt were studied by dynamic shear rheological test.The results showed that the PPA modifier improved the rheological properties of asphalt at different temperatures and different aging conditions,adding PPA can significantly enhance its high temperature performance.However,PPA has a negative impact on the fatigue properties of asphalt.With the increase of PPA content,the anti-fatigue ability of modified asphalt becomes worse.The effects of different modifiers on the low temperature performance of modified asphalt were studied by bending beam rheometer and viscoelastic theory.The results show that the PPA and PPA modified asphalt can improve the low temperature performance of PPA and PPA,reduced the storage,increased the dissipation energy and enhanced the stress relaxation ability.