<p>Aging is a complex phenomenon as it involves hardening, oxidation and loss of volatiles which causes change in physical, chemical, rheological and morphological properties of binder resulting in reduced service life of flexible pavements. The objective of the study is to evaluate the variation of rheological, chemical and morphological properties of modified binders from different sources with aging. For this purpose, CRMB 55 was procured from two different sources and were tested using Dynamic Shear Rheometer (DSR), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The addition of crumb rubber improved the rutting resistance of binder at high temperatures. Particle size of crumb rubber used has significant effect on the properties of modified binders i.e., modified binder with larger size and high crumb rubber content possesses better resistance to traffic and loading conditions. CRMB sample with higher crumb rubber content showed better anti-rutting performance and higher resistance to permanent deformation.</p>