Study On The Effect Of PPA And Sulfur On The Performance Of Polymer Modified Asphalt

In the study of Polyphosphoric Acid(PPA)and polymer compound modified asphalt,it is easy to appear the problems of poor aging resistance and poor storage stability and other issues,and the application of PPA in high viscosity asphalt is lack,and the characteristics and mechanism of PPA and different polymer modification are not deep enough.In view of this,EVA,SIS,SEBS and SBS modified asphalt were modified with PPA and sulfur(S)respectively in this paper.Physical properties,high and low temperature rheology(DSR,BBR)and infrared,thermal gravimetric and other material structure means were used to reveal the effect and mechanism of PPA and S on the high and low temperature performance,aging resistance and storage stability of polymer modified asphalt.Specific work and conclusions are as follows:Firstly,the effects of PPA and S on the physical properties of polymer modified asphalt such as EVA were studied by means of softening point and penetration and so on.The research shows that adding a small amount of PPA can significantly improve the high temperature performance of polymer modified asphalt,and has no adverse effect on other properties,but it does not improve the aging resistance and storage stability.The experimental results show that the reasonal amount of PPA is 0.5%?1%,and the storage stability of SBS,SIS and PPA modified asphalt is improved by sulfur.In order to study processing technology and formula about PPA applied in high viscosity asphalt,the softing point,viscosity toughness,toughness and dynamic viscosity of 60? were tested to explore the application effect of PPA in SBS high viscosity asphalt.The research shows that the best process is to mix the plasticizer and matrix asphalt in advance,and then add SBS and PPA.PPA reduces the 60 ?dynamic viscosity of SBS high viscosity asphalt.On the premise of not reducing the softening point,ductility,ductility and toughness of modified asphalt,0.5%PPA can reduce the content of 1%SBS in high viscosity asphalt.For the effect of rheological properties of PPA/S and polymer modified asphalt,the temperature and frequency sweep,creep and low temperature rheological were tested by the DSR and BBR.The complex shear modulus,phase angle,viscosity and stiffness modulus of modified asphalt were analyzed.The results show that PPA can improve the high temperature and low temperature cracking resistance of SIS modified asphalt and SB S high viscosity asphalt,the low temperature performance of SIS modified asphalt can be further improved by adding sulfur.The modification mechanism of the modified asphalt was studied by means of infrared spectroscopy,thermal analysis and morphology analysis.The results show that PPA gel can improve the thermal stability of EVA,SEBS,SIS and SBS high viscosity asphalt before aging.PPA reduce the compatibility of SIS and SEBS modified asphalt,sulfur crosslinking improved the compatibility of PPA with EVA and SIS modified asphalt.Based on the above study,PPA can improve the high temperature performance of polymer modified asphalt,but could not improve the aging resistance and storage stability.The dosage of PPA should be appropriate controlled.The storage stability and aging resistance of modified asphalt can be further improved by adding sulfur.The adding order of modifier should be paied attention when PPA applied in high viscosity asphalt.Based on the above,we can provide a reference for the application of PPA and S in polymer modified asphalt.