Research On The Technical Characteristic Of The Polyphosphoric Acid Modified Asphalt And Asphalt Mixture

The traditional polymer modified bitumen is mostly the physical modification, populerly, thecompatibility of asphalt and modifier is poor,lack of thermal stability,processing complex and highcost.These reasons Restricts the performance of modified asphalt.Add polyphosphoric acid in asphalt, the chemical modification can significantly improve the performance of asphalt concretepavement.Polyphosphoric acid modified asphalt has a promising tomorrow for itsless cost, simpleprocess. Polyphosphoric acid modified asphalt has not widely used in China,the lack ofsystematic study study of materials,design, evaluation criteria, mechanism analysisrestrictits its application,To some extent.This paper make the combination of experimental study and theoretical analysis, conducted a in-depth study from a different perspective on the technical performance of the polyphosphoric acid modified asphalt mixture.This paper make a connection of the type of asphlt, Polyphosphoric acid level and content, polymertype and content with the technical performance of Polyphosphoric acid modified asphalt.The results show that the polyphosphoric acid can effectively improve the asphalt temperature-sensitive, high temperature stability, storage stability and aging resistance, the reasonable content of polyphosphoric acid is within 0.5%—1%.Adding SBS and SBR polymer, can effectively improve the low temperature crack resistance of the polyphosphoric acid modified asphalt.This article selects polyphosphoric acid modified asphalt mixture AC-13 and AC-20,as mixture design and pavement performance research example.The rutting test of asphalt mixture evaluates the capacity of deformation resistance; immersion marshall test, freeze-thaw splitting test and dynamic water scouring experiment evaluates the mixture water stability; bending test at low temperature evaluates anti cracking performance; bending test at low temperature before and after aging split test evaluates the anti aging performance. The results shows that: polyphosphoric acid has a significant effect in improving the high temperature stability and the anti aging property of the asphalt mixture, improve water stability to some extent, but it has a certain negative effect on the low temperature anti-cracking performance. Taking Chinsese Asphalt Pavement climatic zoning, road performance results and economic benefit analysis into account, this paper recommend the mixed mode of the polyphosphoric acid in modifing asphalt. At last put forward the polyphosphoric acid modified asphalt evaluation index system.The construction and performance testing of Jing-Kong test road verified the conclusion of the indoor test. Through this process, this paper summarizes the construction technology and quality control methods of polyphosphoric acid modified asphalt concrete pavement. Theeconomical analysis shows that polyphosphoric acid modified asphalt has favorable economic and social benefits and broad application prospects.