Impact of Aging on the Performance of Microencapsulated Phase Change Materials in Asphalt Binder across Variable Temperature Range

This study assesses the thermal stability, thermoregulation ability, and performance of microencapsulated phase change materials (MPCMs) in asphalt binders considering different aging levels. Three MPCMs having melting points of 6°C, 28°C, and 37°C (namely M6, M28, and M37) were incorporated into PG 58-28 and PG 64-22 binders. After that, each binder was aged using rolling thin film oven (RTFO) and pressure aging vessel (PAV). The thermal stability of MPCM-modified binders was assessed by measuring enthalpy at different aging levels, and respective performance was evaluated using complex shear modulus (G*) and Glover–Rowe (G-R) parameters. The performance within the thermoregulation range was assessed using percentage change in G* and Superpave fatigue parameter (G*·Sin[δ]) from temperature ramp tests (TRT). Results showed that aging reduced the enthalpy of MPCM binders, but M6 and M28 exhibited good thermal stability in both binders compared with M37. In addition, stiff binders and lower dosages tend to have less enthalpy. At RTFO level, all dosages of M6 and M28 in PG 58-28 demonstrated improved rutting resistance, whereas only M28-20% in PG 64-22 showed enhanced rutting resistance. At PAV level, all samples (except M28-20% in PG 64-22) showed improved cracking resistance compared with the control binders. TRT confirmed that surviving M6 and M28 particles enhanced G*·Sin(δ) at the PAV level within the thermoregulation range. M37 showed thermal instability in both binders at RTFO and PAV levels. In summary, M6 and M28 in PG 58-28 binders demonstrated high thermal stability and enhanced cracking resistance, making this combination suitable for practical asphalt applications.