Application of bitumen rheological parameters to predict thermal cracking behavior of polymer modified asphalt mixture

Effects of bitumen rheology on low temperature properties of polymer modified asphalt mixtures were studied. The rheology of the bitumens were characterized using SHRP bending beam rheometer (BBR), and the low temperature properties of the mixtures were evaluated by indirect tensile strength test and creep compliance test at different polymer contents. The results indicate that, in most cases, polymer modification do not show significant low temperature performance grade improvements as compared to the corresponding base bitumen. The mixture fracture temperature does not match as well bitumen cracking temperature. Based on the results obtained, it was concluded that not all of the bitumens with same low temperature performance grade may perform the same. The results indicate that it would be very difficult to establish general relationships between properties of polymer modified bitumen and the performance of pavement at low temperatures leading to the conclusion that the most sensible would be to evaluate the performance on the polymer modified asphalt mixture.