Characterization of effects of reclaimed asphalt pavement (RAP) source and content on dynamic modulus of hot mix asphalt concrete.

• Effects of source and content of reclaimed asphalt pavement were characterised. • Two new parameters were proposed to analyse trend and variations of dynamic modulus of asphalt concrete. • Effects of the reclaimed materials on activation energy of asphalt binder were evaluated. • The trend of relative dynamic modulus depends on source and content at frequency and temperature sweeps. • There are some correlations between the activation energy of binders and dynamic modulus of mixes. 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. [ABSTRACT FROM AUTHOR]