The topic addressed in this study is relevant and timely, particularly given the growing attention to sustainability in pavement engineering. The investigation into REOB-modified bitumen contributes meaningfully to understanding the challenges and potential of using alternative binders. However, I find the structure of the paper somewhat unsatisfactory. In its current form, the paper first presents mechanical and rheological performance results and only later attempts to interpret these findings through chemical analysis.

 I believe the paper would benefit from a reversed structure: it would be more logical and scientifically robust to first analyze the chemical composition of the materials, and then explain the observed physical behavior based on these findings. As it stands, the paper lacks a clear explanation of the mechanisms behind the unexpected material behavior, such as the increased stiffness despite low PEN grades and soft rheological responses in DSR. This article is commendable, presenting a thorough analysis. I recommend comparing the findings with those of earlier research for a more comprehensive understanding. The writing is clear and the methodology appears robust.