Composition And Performances Research On The Asphalt Of The Stress Absorbing Layer Of Modified Asphalt Mix

Setting the stress absorbing layer in the structures of the asphalt overlay on old concrete and newly built asphalt pavement on rigid or semirigid base can well solve the problem of the reflective cracks, more and more engineers and technicians are focusing on it. But for a long time, the domestic studies on it are few. Therefore, the application of the the stress absorbing layer is limited in the reconstruction projects.According to the technical requirements of the stress absorbing layer, this paper analysed the influences of the basic asphalt, modifier, stabilizer, compatilizer and the modified technology on the asphalt performances of the stress absorbing layer. Meanwhile, it also proposed the optimum modified formula.As the stress absorbing layer requires its asphalt to have good low temperature performance, this paper studied on the low temperature evaluation indexs of the Sampave asphalt through the force ductility test, and verified the anti-cracking performance of the asphalt mixture in the cold conditions, it put forward (Fl-Fz)/(Fo-Fz) and W2/W1 as the low temperature evaluation indexs of the asphalt. Based on the segregation phenomenon of the modified asphalt during the transportation and storage, it researched the thermal stability of the Sampave asphalt through the segregation test, the result indicated that D-value of the segregation could meet the requirements of the specification. Furthermore, the results of the stability test during the transportation and storage showed that Sampave asphalt had the better performance of heat stability.This paper chose five kinds asphalt which included the Sampave, three types of the modified asphalt and the basic asphalt to study on the rheological performances in the high, middle and low temperature.The results proved that the Sampave asphalt had the better anti-aged performance, the better anti-cracking performance in the low temperature and the better anti-fatigue performance in the room temperature.