Study On Road Use Of Waste Plastic Bag Asphalt Mixture

China's highway mileage has ranked the first in the world.A large part of the highway pavement and urban road pavement are paved with asphalt mixture,but there are cracks,flooding,pits,ruts and other damage phenomena in the operation process,and the rutting disease is the most serious.Plastic bags are widely used in people's lives and seldom reused.White pollution has become an increasingly serious environmental problem in modern society.In order to solve this problem,this paper proposes to mix waste plastic bags with asphalt for modification,which can improve the road performance of asphalt mixture while consuming plastic bags.Comparing waste plastic asphalt mixture with ordinary asphalt mixture,rutting test,immersion Marshall test and shear test were carried out by mixing waste plastic bag asphalt mixture.Modified asphalt was prepared by mixing waste plastic bags with hot base asphalt.By comparing the penetration,ductility and softening point of asphalt with the modified asphalt mixed with waste plastic bags,it is concluded that the penetration,ductility and softening point of modified asphalt decrease with the increase of the content of waste plastic bags,which indicates that the high temperature performance of modified asphalt is improved,but it is not suitable for low temperature environment.Asphalt is weak acidic,basalt is alkaline aggregate,is a good raw material for mixtures,but limestone powder is used in this test.After standard Marshall test,the amount of aggregate and mineral powder used in 1 # aggregate 2 # aggregate 3 #aggregate is 22%,30%,44% and 4% respectively.The optimum oil-stone ratio is4.6% by calculating the gross volume density,voidage,stability and saturation ofdifferent oil-stone ratios.With the increase of plastic bags,the high temperature performance of asphalt mixture increases,reaching the peak value when the content of plastic bags is 0.6%.This is because the addition of plastic bags improves the viscosity of asphalt and increases the surface energy of asphalt mortar,thus forming a more stable interface after bonding with aggregates.However,the increase of the content of asphalt mortar will agglomerate the plastic bags and affect the dispersion system of asphalt mortar,resulting in deterioration of performance.The water immersion Marshall test of modified asphalt mixture shows that the best content of waste plastic bags with 0.6% is the strongest water damage resistance.This is consistent with the conclusion deduced from the surface energy theory shown above.The rutting of asphalt mixtures is mainly caused by the weakening of shear resistance of asphalt mixtures under high temperature,resulting in cumulative plastic deformation.The shear test of asphalt mixture shows that the shear resistance of modified asphalt mixture is the strongest when the content of asphalt mixture is 0.2%.