Study On The Performance Of Reactive Blending Modified Asphalt And Asphalt Mixture

Asphalt pavement has many advantages,such as high strength,good stability,good impermeability and so on.It is widely used in highway construction in China.But at present,the number of all kinds of vehicles in our country is increasing at a relatively fast speed,especially heavy trailers and trucks,which load asphalt pavement at different speeds or frequencies continuously,which puts forward higher requirements for the performance of asphalt pavement.In addition,although SBR modified asphalt has excellent low temperature performance and is suitable for areas with low temperature and large temperature difference,it is easy to stratify and segregate when SBR modified asphalt is prepared by physical blending.Therefore,this paper focuses on the preparation of modified asphalt by chemical reaction blending to improve its segregation phenomenon and improve the performance of asphalt and mixture.This paper is mainly divided into three parts: the study of reactive blending modified asphalt,the performance of reactive blending modified asphalt and the performance of reactive blending modified asphalt mixture.1.In addition to SBR modifier,there are DTDM vulcanizer,PPA accelerator and kaolin stabilizer in reactive blending modified asphalt.In the study of the optimum dosage of additives,three levels were selected for each factor,nine test numbers were designed by orthogonal test,and reactive blending modified asphalt was prepared in the same way.The conventional index,135 viscosity index and 5 ductility index after RTFOT were determined respectively.Range analysis method was used to analyze the influence degree of factors under each test index.Topsis analysis method was used to synthetically analyze multi-index and find out the optimum dosage of each additive.2.In the study of the performance of reactive blending modified asphalt,the viscoelastic properties,temperature sensitivity and storage stability were studied and analyzed.The dynamic shear rheological test was used to evaluate its viscoelastic properties,which was divided into two parts: temperature scanning test and frequency scanning test.Then,the complex shear modulus and rutting resistance factor obtained from the temperature scanning test were used to analyze the temperature sensitivity of the blended modified asphalt.The segregation test was used to evaluate the storage stability of asphalt,and the effect of additives on the storage stability of asphalt was evaluated.3.When studying the pavement performance of asphalt mixtures,the AC-13 gradation upper and lower limit median required by the specifications is taken as the test gradation,and the optimum asphalt-aggregate ratio is determined.Then the asphalt mixtures are prepared to evaluate the pavement performance of reactive blending modified asphalt mixtures.Topsis analysis finally determined that the additive content of DTDM,PPA,kaolin and SBR should be 0.8%,1%,0.6% and 4.5% respectively.DTDM promotes the formation of stable network structure between SBR and asphalt,which has a certain effect on improving the high temperature performance of reactive blending modified asphalt;PPA can effectively improve the high temperature resistance of asphalt;the temperature sensitivity of reactive blending modified asphalt is worse than that of SBS modified asphalt;kaolin can significantly improve the storage stability of reactive blending modified asphalt.The high temperature performance and water stability of reactive blend modified asphalt mixture are inferior to SBS modified asphalt,but it has certain advantages in low temperature crack resistance and fatigue resistance.