Application Research Of Composite Modified Asphalt On Pervious Asphalt Pavement

Pervious asphalt pavement is a kind of pavement which uses macroporous mixture as surface layer and dense mixture as middle and lower asphalt surface layer.This kind of pavement can effectively reduce noise,improve the skid resistance of the pavement and quickly drain water,as well as prevent traffic mist and "water drift".Because of the high void ratio of permeable asphalt pavement,it is necessary to use high-viscous asphalt.The performance of high-viscous asphalt directly affects the performance of mixtures,so the development of high-performance high-viscous asphalt is very important for the promotion of permeable asphalt pavement.In this paper,25 groups of specimens were prepared by adding HVA modifier and rubber powder to 70 # base asphalt.The relationship between the amount of HVA and rubber powder and asphalt penetration,ductility,softening point and dynamic viscosity at 60 C was found out through experiments,and the optimum mixing of HVA and rubber powder was designed.Modified asphalt suitable for permeable asphalt pavement was prepared.At the same time,compared with SBS modified asphalt,the anti-aging performance of modified asphalt has been significantly improved.The voidage requirement of pervious asphalt pavement in various countries is studied.The target voidage is 18%,20% and 22%.The gradation of mixture is designed by controlling the passing rate of 2.36 mm sieve hole.The optimum asphalt-aggregate ratio is determined by dispersion test and leak test,and the asphalt mixture is prepared.The high temperature stability,low temperature crack resistance,water stability and water permeability coefficient of self-made high viscous asphalt mixture and SBS modified asphalt mixture were studied through experiments.The test results show that the two mixtures meet the requirements of specifications,and the high temperature stability,low temperature crack resistance and water stability of self-made high-viscous asphalt mixtures are better than SBS modified asphalt mixtures,but the water permeability coefficient of self-made high-viscous asphalt mixtures is smaller than that of SBS modified asphalt mixtures.The influence of void fraction of asphalt mixture on the pavement performance of asphalt mixture is studied through experiments.The high temperature stability,low temperature crack resistance and water stability of asphalt mixture will decrease with the increase of voidage,and the low temperature crack resistance of asphalt mixture is less affected by voidage.The permeability coefficient of asphalt mixture increases with the increase of voidage,and there is a linear relationship between the permeability coefficient and voidage.The target void ratio is 20% to carry out aging test.The oven heating method is used to aging the asphalt mixture,and the aging asphalt mixture is tested to study the high temperature stability,low temperature crack resistance and water stability of the mixture.The test shows that the aging resistance of self-made high-viscous asphalt mixture is stronger than that of SBS modified asphalt mixture.