Study On The Performance Of Polyphosphate Modified Bio Asphalt And Its Mixture

In recent years,the research on bioasphalts in road materials has gradually become a hotspot.However,there are few comparative studies on bioasphalts from different biomass sources,and the performance defects of bioasphalts are mainly improved by polymer modifier.Therefore,the purpose of this paper is to compare and analyze the performance differences of different kinds of bioasphalts,and to explore the influence of polyphosphoric acid on the performance of different bioasphalts.In this paper,bio oil I and bio oil II were mixed with 70# petroleum asphalt to prepare bio asphalt I and bio asphalt II.In the bio asphalt,PPA modified bio asphalt I and PPA modified bio asphalt II were prepared by mixing with polyphosphate.Then the penetration test,softening point test,ductility test,film oven test and adhesion test were used to analyze the performance of two kinds of bio asphalt and PPA modified bio asphalt.The test results show that there are great differences between the two kinds of bio asphalt.The increase of bio oil I ratio in bio bitumen will increase the consistency and high temperature performance of asphalt,and decrease the performance of low temperature and anti-aging,but it will not adversely affect the adhesion between asphalt and aggregate.The increase of bio oil II content in bio bitumen can significantly improve the ductility of matrix asphalt at low temperature,but it will lead to a decrease in asphalt consistency,high temperature resistance,aging resistance and adhesion to aggregates.Polyphosphate was selected to optimize the performance of bio asphalt I and bio asphalt II.The incorporation of polyphosphoric acid leads to a decrease in the low temperature properties of the 2 kinds of bio bitumen,but the consistency,high temperature performance and aging resistance can be improved.Polyphosphate has no adverse effect on the adhesion between bio asphalt I and aggregate,and can improve the adhesion between bio asphalt II and aggregate.Comprehensive analysis shows that polyphosphate can not solve the problem of poor low-temperature performance of bio asphalt I,but reduce its low-temperature deformation resistance.Therefore,it is considered that bio asphalt I is not suitable for performance improvement with polyphosphate alone.Due to the complementary effect of bio oil II and polyphosphate on the performance of asphalt,the asphalt binder prepared by 10% bio oil II + 70# base asphalt + 0.9% PPA(0.9% PPA modified bio asphalt II for short)can maintain better performance,so this paper will test and analyze its mixture to verify the performance of asphalt binder.Through rut test,low temperature bending test and 48 h immersion Marshall test 0.9%PPA The performance of modified biological asphalt II mixture and 70# petroleum asphalt mixture were compared and analyzed.The results show that: 0.9%PPA The modified asphalt II mixture has excellent low-temperature crack resistance and good water stability,but its high-temperature performance is slightly lower than that of the base asphalt mixture.