Synergistic activation energies in recycled binder blends with composite rejuvenator (CMR)

The use of compose rejuvenator (CMR) offers a promising solution for restoring reclaimed asphalt pavement (RAP) binder performance. This study investigates a novel CMR – comprising waste engine oil, crumb rubber, styrene–butadiene–styrene, and Sasobit – and its effects on rheological and kinetic properties of RAP binders. Blends containing 5%–50% CMR were evaluated using Fourier-transform infrared spectroscopy, dynamic shear rheometer testing, and Arrhenius-based kinetic modelling. Activation energies for aging (Eaa), cracking (Eac), and permanent deformation (Eap) were determined to quantify stiffness, durability, and deformation resistance. Results show that the CMR effectively mitigates aging by reducing stiffness while improving flexibily and fatigue performance. The kinetic parameters were validated using a mass-composite activation energy model, with predictions aligning closely with experimental results. This study provides a kinetics-guided framework for optimising CMR content in RAP binders, balancing stiffness, durability, and deformation resistance, contributing to more sustainable pavement applications.