Preparation Of Dry Mix High Viscosity Modifier And Application In Porous Asphalt Mixture

Drainage asphalt pavements require high viscosity asphalt with high adhesion and excellent rheological properties due to the large void ratio and the susceptibility of the asphalt binder to external environmental influences.In wet high viscosity asphalt,the modifier is prone to segregation with the asphalt,resulting in poor storage stability.Due to the special characteristics of the dry mix process,its production of asphalt mixes eliminates the preparation and transportation of modified asphalt,effectively solving the problem of lack of stability of wet high viscosity asphalt.At present,China’s commercially available direct-injection modifiers are generally expensive.Therefore,the development of dry mix high viscosity modifier with independent intellectual property rights and to meet the performance of the road is the main issue in the development of functional pavement today.To meet the performance requirements of drainage asphalt pavement,thermoplastic elastomer,softening agent,adhesion promoter,solubilizer and anti-aging agent were used as the main factors in this paper.The dry mix high viscosity modifier(XA)was prepared by mixing test and by dense refining,extrusion and shear granulation process.With penetration,softening point,5 ℃ ductility,and 60 ℃ dynamic viscosity as evaluation indicators,the influence of various factors on the performance of high viscosity asphalt was explored through regression model variance analysis.According to the above results,the compound system of the XA dry mix high viscosity modifier was optimized,and the feasibility and process parameters of modifier preparation were determined.Two commercially available high viscosity modifiers were selected as the control group(TY,TPS).Through solubility parameter analysis,infrared analysis,differential scanning calorimetry analysis,surface energy analysis,and fluorescence microanalysis,the compatibility relationship between matrix asphalt and three dry mix high viscosity modifiers was comprehensively explored.The results show that XA modifier has the best compatibility with matrix asphalt,followed by TPS and TY modifier.The conventional technical indexes and storage stability of high viscosity asphalt were compared to explore the best dosage of three modifiers.The recommended dosage of TY,XA,and TPS high viscosity modifiers is 12%,12%,and 15% respectively.The aging resistance of high viscosity asphalt was studied and the results showed that the high temperature and low temperature performance of XA high viscosity asphalt after RTFOT and PAV were better than the other two modified asphalts The rheological properties of high viscosity asphalt at high and low temperatures were studied with DSR and BBR.The results show that the addition of modifiers can effectively improve the hightemperature deformation resistance,creep recovery ability,and resistance to low-temperature cracking of asphalt.The final gradation was determined based on the relationship between the initial asphalt dosage and the void ratio of XA high-viscosity asphalt mixture.The effects of dry and wet processes on the road performance of the three high-viscosity asphalt mixtures were compared and analyzed by evaluating the dynamic stability,maximum bending tensile strain,freeze-thaw splitting strength ratio,residual stability,and immersion fly-away loss rate of TY,XA,and TPS asphalt mixtures.The results showed that TY high viscosity asphalt mixture exhibited more outstanding road performance,followed by XA high viscosity asphalt mixture and TPS high viscosity asphalt mixture.