In this paper, the effect of physical hardening and aging temperatures on the low temperature rheological properties of the asphalt binder is experimentally investigated and modelled. First, Dynamic Shear Rheometer (DSR) tests are performed from −30°C to 80°C on four virgin asphalt binders and the corresponding long-term aged binders, which were previously short-term aged at three different temperatures (123°C, 143°C, and 163°C). Master curves are generated to evaluate the impact of aging temperatures, while the effect of physical hardening is also addressed through a simple testing procedure. Then, Bending Beam Rheometer (BBR) tests are conducted under three different conditioning times (1 h, 24 h, and 72 h) for the same materials, followed by the calculation and comparison of creep stiffness, S(t) and relaxation parameter, m-value. In addition, the Huet model is fitted to the experimental data. Finally, the relationship between the time domain complex modulus based on DSR and the creep stiffness obtained with the BBR at different conditioning time is established, and the critical cracking temperatures are calculated and compared. Results indicate that physical hardening causes a significant increase in complex shear modulus and creep stiffness for DSR and BBR, respectively. This trend is remarkable between the first 60 minutes and 24 h while only a moderate contribution can be observed when conditioning time is extended. Linear correlations can be observed between the DSR and BBR results at different conditioning time. No particular storage time leads to equivalent E(t) master curves for BBR and DSR; the curve of 24 h seems to be a compromise in terms of experimental and time costs. In addition, the reduced aging temperature can significantly mitigate the effect of physical hardening, while only a slight improvement can be found in the aging properties of asphalt binders.

This recommendation is based on the results of an inter-laboratory study organised by the RILEM technical committee TC 264-RAP "Asphalt Pavement Recycling"—Task Group 3 (TG3) focusing on Asphalt Binder for Recycled Asphalt Mixture. The TG3 aimed to evaluate the effect of a specific family of materials known as asphalt recycling agent (ARA) on the aged binder under different configurations. Even though ageing is an irreversible phenomenon, effective ARA must have the capability to improve the flexibility of the bituminous materials and their resistance against cracking susceptibility with no adverse effect on the rutting resistance of pavements containing reclaimed asphalt. A total of 17 participating laboratories analysed the properties of binder blends composed of aged binder from reclaimed asphalt in three different contents (60, 80, 100%), ARA and virgin binder. The physical properties of the blends were thoroughly evaluated through traditional and rheological binder testing. This recommendation proposes to restore the original material properties at low and intermediate temperatures (i.e. cracking resistance) while balancing the high-temperature characteristics (i.e. rutting susceptibility) with durable impact throughout the progression of ageing phenomena. Therefore, useing of the Dynamic Shear Rheometer is foreseen as a more suitable and sustainable means to evaluate binder blends containing an asphalt recycling agent. Compared with conventional testing, the proposed approach requires fewer materials while resulting in a faster experimental procedure with one single test.