Study On The Effect Of Warm Mixing Agent Based On Waste Plastic Pyrolysis Products On Asphalt Performance

With the development of economy,the production of waste plastics is increasing year by year,and the white pollution is becoming more and more serious.Warm mixing agent has become a hot spot in recent years because of its characteristics of reducing asphalt high temperature viscosity and reducing pollution gas emission in asphalt pavement construction.Based on this,this paper proposes to prepare waxy asphalt warm mixing agent from polypropylene(PP)waste plastics by cracking method to promote the utilization of waste plastics.The main contents of the study are as follows:A series of waxy modifiers were prepared by cracking PP plastics under different conditions,and then the cracked wax was added to matrix asphalt to obtain modified asphalt.Through three index tests,dynamic shear rheometer(DSR),Brinell rotating viscometer(RV),adhesion test,Fourier transform infrared spectroscopy(FTIR)and differential scanning Calorimeter(DSC)were used to study the high temperature properties,low temperature properties,warm mixing effect,adhesion properties,Viscoelastic properties and functional group changes of modified asphalt.Studies have shown that:By controlling the cracking conditions,360??T?400?;0.1Mpa?T?1.0Mpa range cracking wax modifiers can be divided into two categories: T?360?(at different pressure conditions)and P=0.1Mpa(at 360? and 380?),which can greatly improve the high temperature performance.However,the cracking wax modifier with no warm mixing effect.T?380? and P?0.5Mpa.the pyrolysis wax warm mixing agent with improved warm mixing effect,water stability and high temperature performance can be obtained.Cracking wax can improve the surface energy(mainly increased nonpolar component)and adhesion properties of matrix asphalt.Anti-spalling performance,water stability.With the increase of cracking temperature,the low temperature performance,warm mixing effect,adhesion property,spalling resistance and water stability of the modified asphalt were improved,but the high temperature performance decreased.With the increase of cracking pressure,the low temperature performance and warm mixing effect of modified asphalt are improved,but the high temperature performance and plastic temperature range decrease.The optimum production conditions of pyrolysis wax warm mixing agent are as follows: T?400 ?,P ?0.5Mpa.the optimum content is 6%.The viscosity of the corresponding asphalt phase is about 34% lower than that of the matrix asphalt,and the high temperature performance of the matrix asphalt is improved at the same time.The added value of rut factor after short-term aging,the service life of asphalt pavement under higher speed and higher load,the viscosity at 60?,the ability to resist slip deformation and the ability to recover deformation.The optimum production conditions of pyrolysis wax warm mixing agent are as follows: T?400 ?,P?0.5Mpa.the optimum content is 6%.The viscosity of the corresponding asphalt phase is about 34% lower than that of the matrix asphalt,and the high temperature performance of the matrix asphalt is improved at the same time.The added value of rut factor after short-term aging,the service life of asphalt pavement under higher speed and higher load,the viscosity at 60?,the ability to resist slip deformation and the ability to recover deformation.The warm mixing mechanism of PP cracking wax warm mixing agent may be that the cracking wax has a variety of molecular chain structures,in which some segments are embedded in asphalt molecules,and after stretching,the "reticular" structure exists stably in asphalt.This improves the Visco-elastic characteristics of asphalt,and then improves the viscosity of asphalt at 60?.With the increase of asphalt temperature,when the temperature exceeds 110?,the cracking wax warm mixture changes from high elastic state to viscous flow state,and exists in asphalt with low molecular weight saturated hydrocarbon,which acts as saturated and aromatic components.The asphaltene in asphalt is dispersed in the form of dispersed medium,and the effect of lubrication and viscosity reduction is finally achieved.