Characterization of polymer modified asphalt for rutting and cracking potential using dynamic shear rheometer

In Pakistan, flexible pavements are experiencing a high rate of deterioration due to rutting and fatigue cracking. In order to minimize these problems, it is important to characterize the locally available asphalts at a full range of temperature and also to develop appropriate polymer modified asphalts in the laboratory that can be used to improve the pavement performance. In order to achieve objective virgin asphalt samples from Attock oil refinery were obtained and then six polymer modified asphalt samples were prepared in the laboratory by using Elvaloy (R) RET polymer. The rheological properties were obtained by using Dynamic Shear Rheometer at temperature range from intermediate to high and at a frequency of 10 rad/s. The finding of analysis revealed that polymer modification has significant effect in enhancing the elastic behavior and reducing the viscous behavior of asphalt. The results showed that there is rapid change in visco-elastic behavior of polymer modified asphalt from 1.35% to 1.70% of polymer content but slight change occurred from 1.70% to 2.0 %. Therefore, it recommends that optimum content of polymer for modification is lying between three mentioned values. The most important finding is that a decrease in the temperature susceptibility has observed in case of laboratory polymer modified asphalt that makes the asphalt more suitable for use to control rutting and cracking potential in extreme climatic regimes of Pakistan. The results of prediction models indicate that Witczak models of asphalt have good predictability both for virgin and polymer modified asphalts.