Thermal and rheology analysis of bitumen modified with waste polybutadiene rubber

The limitation in the application of pure bitumen for producing asphalt mixtures is due to the increased vehicle load and the effects of environmental factors, which results in the premature deterioration involving the rutting in asphalt layers. In this study, the waste polybutadiene rubber was used in combination with Sasobit to improve thermal resistance and rheology behavior of bitumen. For this purpose, the bitumen samples were prepared with different percentages of additives using the high shear mixer. The results of the study showed that adding waste polybutadiene rubber to the bitumen improved thermal resistance, rutting and fatigue resistance potential, and generally, middle and high temperature performance. Accordingly, the combinations of 2.3%PBR and 2.3%PBR+2.5%Sasobit increase the high-temperature bitumen performance by one and two grades, respectively. The combinations of 2.3%PBR increase fatigue life and add Sasobit, and also adding more than 2.3% PBR reduce fatigue resistance. The results of TGA show that there is good agreement between the results of these technique and other results, which can help assess the results accurately at macromolecular level.