Impact of Wetting and Drying Cycles on Reclaimed Asphalt Pavement and Warm Mix Asphalt Performance: Comparison with Long-Term Aging Conditions for Pavement Durability

The primary objective of this study was to evaluate the effect of reclaimed asphalt pavement (RAP) and warm mix asphalt (WMA, Sasobit) combinations on moisture susceptibility, fatigue resistance, rutting behavior, Marshall stability, and aging of bound base-course mixes. Two RAP sources (from pavements with different service lives) were incorporated at ≈ 35 % and ≈ 70 % by mix mass, and mixtures were produced as hot mix asphalt (HMA) and WMA. Specimens were conditioned under two environmental regimes’ standardized long-term aging (LTA) and accelerated alternate wetting–drying (W&D) cycles and tested for Marshall stability, indirect tensile strength (dry/wet), rutting resistance (dynamic stability), and fatigue life (four-point bending). Alternate W&D cycles produced measurable degradation: fatigue life declined by roughly 10%–21% (dependent on RAP content); and moisture resistance (indirect tensile ratio) decreased by about 4%–9% in several WMA cases. LTA tended to increase stiffness and Marshall stability but did not reproduce the same moisture-driven losses observed under W&D. The results indicate a trade-off: WMA with Sasobit improves workability and can reduce some aging-related losses at moderate RAP contents, yet lower mixing/compaction temperatures may limit RAP–virgin binder blending and increase moisture vulnerability unless antistripping measures are applied. Therefore, WMA is a promising option for RAP-inclusive mixes when moisture risk is managed. It should not be adopted unconditionally in moisture-prone environments.