<p>Warm Mix Asphalt (WMA) additives are designed to reduce the viscosity of asphalt binders. This property allows mixing, compaction, and placement at lower temperatures than traditional hot mix asphalt. This temperature reduction can lead to significant energy savings and environmental benefits, such as reduced greenhouse gas emissions and improved working conditions. However, it is essential to thoroughly evaluate how these additives influence the mechanical and chemical performance of the binder, particularly in terms of rutting resistance and fatigue life. This study examines the rheological, physical, and chemical properties of a control SBS polymer modified binder (PMB) with WMA additives. The binder characteristics were assessed through viscosity testing, PG grading, DSR frequency sweep testing, and conventional penetration and softening point tests. FTIR spectroscopy and XRD were further used to examine chemical and microstructural change of the control and modified asphalt binders. The WMA additive used in this study is Wetbond. The PMB was blended with four different concentrations (0.2%, 0.4%, 0.6%, and 0.8%) of Wetbond by weight of asphalt binder, resulting in the preparation of five binders in total within the laboratory setting. Results indicate that adding Wetbond decreased PMB viscosity and penetration and increased the softening point up to 0.6% concentration of Wetbond. Wetbond demonstrated the ability to elevate PG levels and improve PMB’s rutting and fatigue performance. This study underscores that viscosity alone should not be the sole criterion for selecting a WMA additive, as such additives may adversely affect the short-term and long-term performance of the binder. Hence, careful consideration is essential when choosing a WMA additive for a specific type of binder. The statistical analysis was conducted to see the significance of adding Wetbond into SBS-modified asphalt binders.</p>