Study On Road Performance Of Qingchuan Rock Asphalt/SBR Composite Modified Asphalt And Its Mixture

In order to improve the phenomenon of increasing diseases of Asphalt Pavement,at the same time,it also responds positively to the call of vigorously developing ecological construction in China.It is imperative to develop a new material which can not only have good pavement performance,but also ensure the construction of "green highway".Qingchuan rock asphalt,as a natural resource,not only has abundant reserves,but also has good road performance and reasonable price.It is a rare material.According to a large number of scholars’ research literature on Qingchuan rock asphalt modified asphalt,Qingchuan rock asphalt mixture does have good high temperature,low temperature,water temperature and fatigue resistance,but the low temperature performance is not ideal.The addition of Qingchuan rock asphalt has a great negative impact on the low temperature performance of mixtures.SBR modifier has the ability of elongation and deformation,and can improve the elongation of asphalt binder,thereby improving its low temperature crack resistance.In this study,Qingchuan rock asphalt and SBR modifier were used to modify base asphalt,and a new type of composite modified asphalt was developed,which not only has good high temperature stability,water stability,fatigue resistance,but also can make low temperature crack resistance meet the requirements of specifications.The main contents of this paper are as follows:1.Qingchuan rock asphalt and SBR modifier were added into the base asphalt separately.The content range of Qingchuan rock asphalt and SBR modifier was determined by penetration,softening point,ductility and distribution viscosity of modified asphalt.2.Six groups of additives were designed by uniform design method,and the preparation of composite modifiers was carried out according to the amount of each group of modifiers.Three indexes of composite modified asphalt were tested,including distribution viscosity test,DSR test and rotary film oven aging test.The results show that the high temperature performance,anti-aging performance and low temperature performance of composite modified asphalt are excellent.3.After determining the model,we use Spass software to carry on the regression analysis to the data,and get the corresponding regression equation by using the measured three indexes test value of composite modified asphalt and the distributionviscosity test value.With the standard requirements of SBS modified asphalt widely used nowadays as the index limit,the regression equation is solved by using the software of matlab.The optimum content of Qingchuan rock asphalt and SBR modified asphalt is 4.8% and 6.1% respectively.Composite modified asphalt was prepared according to the optimum dosage of modifier.Through three indexes test and distributed viscosity test,it was found that the compound modified asphalt with the optimum dosage met the performance specification of SBS modified asphalt.4.Comparing the pavement performance of the composite modified asphalt mixture with the base asphalt mixture,Qingchuan rock asphalt mixture and SBS modified asphalt mixture,it is found that the composite modified asphalt has excellent effect in high temperature stability,water stability and fatigue resistance.The low temperature crack resistance meets the specification requirements,but is slightly worse than SBS modified asphalt mixture.