Composite activation energy of aging and cracking kinetics for recycled fine aggregate matrix

The use of reclaimed asphalt pavement (RAP) introduces performance concerns and testing challenges, including binder chemistry changes and labor-intensive procedures. To address these, this study applies Fine Aggregate Matrix (FAM) testing, enabling direct RAP evaluation without binder extraction. FAM mixtures were prepared using 0–3 mm RAP fraction, virgin binders, and two gradation types. Aging activation energy was determined from reference modulus variations. The time-strain superposition model estimated fatigue damage density and cracking activation energy. Results show this model reduces testing time and prevents equipment overheating. Virgin FAMs exhibit higher cracking resistance but lower aging resistance than recycled FAMs, while SBS-modified binders outperform Pen-70. Finer gradations improve cracking resistance but reduce aging resistance. Finally, the mass-composite model predicts activation energies of recycled FAMs and finds minimal error (0.51–2.32%).