The effects of the reclaimed asphalt pavement (RAP) source and content on the dynamic modulus (E *) of hot mix asphalt concrete were characterized. Two parameters were proposed: the non-dimensional dynamic modulus-temperature index (∇E T *) and non-dimensional dynamic modulus-frequency index (∇E fr *). Parameter ∇E fr * indicates the increase of relative E * per unit percent RAP from different sources during frequency and temperature sweeps, while ∇E T * characterizes the reduction of relative E * per 1 °C temperature increase. An analysis of the results showed that ∇E T * of RAP mixes were 6.80% to 12% higher than those of the control samples, indicating less temperature susceptibility. Furthermore, an analysis of ∇E fr * trends showed temperature independency at higher temperature ranges. In addition, the results showed that the activation energy (AE) of the mixes was 1.51 MJ/mol/K to 9.86 MJ/mol/K higher than that of the control samples (without RAP), which depends on the RAP content and source. Moreover, E * linearly increases as AE increases. In conclusion, the increase of intermolecular forces owing to the higher AE in the blended binders increased the mix stiffness, which resulted in a higher E * in mixes containing RAP.