Evaluating the Characteristics of Crumb Rubber Modified Asphalt Binders Produced with Local Bitumen: Case of Kuwait

This research study evaluated the characteristics of crumb rubber modified (CRM) asphalt binders produced with local bitumen. Two different percentages of crumb rubber (CR); 10% and 15% and one bitumen type with penetration (Pen) grade 60/70 were evaluated. The evaluation included viscosity, ductility, penetration, softening point, scanning electron microscopy (SEM) images, and multiple stress creep recovery (MSCR) test. MSCR results showed that the addition of CR to the local bitumen significantly improved the performance grade (PG) of the produced binder as per AASHTO M332 standards. The traffic loading level for both 10% and 15% CRM asphalt binder increased to “Extreme” level at 76°C. Both 10 and 15% CRM binders passed the local Kuwaiti requirement for modified binders, however the 15% CRM binder was found not to be modified with an elastomeric polymer. This can be attributed to the lake of full blending between the CR particles and the binder’s bulk due to the increase in CR percentage.