The objective of this article was to investigate the influence of a rejuvenator of vegetal origin on the behavior of several binder blends at low and high temperatures. An important characteristic of a binder is the critical temperatures that are related to the pavement performance (its susceptibility to temperature change). One fresh binder (50/70 penetration grade binder), a Reclaimed Asphalt Pavement (RAP) binder, and a rejuvenator were blended in different dosages, and a total of 17 binders were tested. Complex shear modulus tests at high and intermediate temperatures and bending beam rheometer tests at low temperatures were performed in order to obtain the critical temperatures. Another objective was to estimate TDSRhighcritical and TBBRlowcritical for all blends from the experimental results of base constituents by using two estimation approaches (a classical and a proposed approach, which is an original input of this work). A statistical analysis was performed in order to highlight their validity. Good correlation was found between the experimental and the estimated results. However, a more accurate estimation was performed with the proposed approach that has the great advantage of requiring only the temperature values and concentrations (a,b,c) for the three base components (respectively, fresh binder, RAP binder, and rejuvenator).