Tribological Investigation of Asphalt Binder Using DSR

One of the key factors in developing an understanding of compaction mechanics is the interfacial friction between the binder and aggregates, and tribological investigations are very useful in this regard. In this study, tribological tests are performed for a range of angular velocities and normal forces such as 5 N, 10 N, and 15 N. Stribeck curves are developed for one unmodified bitumen and two modified bitumen (elastomer and plastomer) at three temperatures of 120 degrees C, 140 degrees C, and 160 degrees C. It is observed that the unmodified binder shows more coefficient of friction than modified binders irrespective of the temperature, whereas the modified bitumen exhibits responses that are dependent on temperature. By studying the different regimes of the Stribeck curve for the different binders, temperatures, and normal forces, it is possible to understand the response of asphalt binders during mixing and compaction.