Dr. Salih Kocak

This paper investigated the rutting potential and continuous grade temperature (C-PG) changes of original, aged, and crumb rubber-modified asphalt binders. The original binder was selected based on the research region, and it had a performance grade (PG) of 58-28. Modifications were performed using a single mesh size #20 CR modifier. C-PG of asphalt binders is determined at high, intermediate, and low temperatures. The multiple stress creep recovery test was conducted to evaluate the rutting performance and traffic grade of asphalt binders at regional high temperature as well as at high PG temperatures. MSCR tests were performed using bob and cup (BC), which is also known as the concentric cylinder, geometry since the use of parallel plate geometry was not allowed for binders with discrete particles larger than 250 microns in size. The results show that the crumb rubber modification improved the original binder's high rutting resistance along with traffic grade bumps and continuous PGs.

Polymer modification of asphalt binders has gained quite popularity in many transportation agencies, primarily due to the superior crack- and rut-resistant performance. However, added cost of polymer modification results in an appreciable increase in the initial cost of an asphalt pavement. There are more economical and sustainable alternatives to polymers, such as the so-called “De-Vulcanized Rubber (DVR)”. Primary advantage of DVR technology is that, it is made from scrap tires and when mixed with asphalt binder, the particles completely dissolve within the binder. Therefore, the final product is a complete fluid, not a suspension. The main objective of this study was to investigate the relative performances of the SBS polymer and DVR in an asphalt binder. The impact of the modifications on performance grade (PG) and fatigue cracking resistance was investigated. The results have shown that more sustainable modification of asphalt binders can be achieved by replacing the entire or some amount of SBS with DVR.