During pavement construction, styrene–butadiene–styrene (SBS) modified asphalt binders (SBS-ABs) undergo short-term thermo-oxidative aging, during which SBS macromolecules degrade concurrently with the stiffening of the asphalt binder. In this paper, the coupled influence of these mechanisms on the rheological behavior of SBS-ABs is investigated over a wide range of angular frequencies and SBS dosages. Rheological results show that at low angular frequencies ( $\omega $ < 1 rad/s), rolling thin film oven (RT-FO) aged SBS-ABs exhibit substantially reduced viscoelastic properties compared with unaged binders at higher service temperatures, including decreases of approximately 50–70% in complex viscosity ( $\eta $ *), storage modulus (G′), and complex modulus (G*). In addition, RTFO-aged binders display phase angle increases of approximately 15–30°, reflecting deterioration of the SBS-maltene-rich network. The strong dependence on slower $\omega $ arises from the sluggish mobility of SBS molecules and the presence of SBS-maltene-rich network in the asphalt binder, and the effect of RT-FO aging is found to be most pronounced at SBS dosages between 3 and 5 wt.%. These results demonstrate that the synergistic effects of SBS polymer degradation and binder stiffening can be effectively characterized only when rheological measurements span a broad frequency range (0.01–10 rad/s) and SBS content (2–7 wt.%). The findings provide practical guidance for SBS-modified binder formulation and performance evaluation during construction-related aging.
