Influence of SBS Polymer on Asphalt Binder Characteristics and Moisture Resistance of Mixtures

This study investigates the effect of Styrene-Butadiene-Styrene (SBS) polymer on asphalt binder properties and the performance of asphalt mixtures. Binder modification was evaluated through penetration, softening point, and rotational viscosity tests, showing that SBS addition enhanced binder stiffness, increased temperature resistance, and improved workability during mixing and compaction. Marshall tests indicated a progressive increase in stability and a gradual reduction in flow with higher SBS content, reflecting improved load-bearing capacity and reduced susceptibility to permanent deformation. Indirect tensile strength (ITS) tests under dry and wet conditions demonstrated enhanced moisture resistance in SBS-modified mixtures. Overall, SBS modification significantly improves both the rheological characteristics of the binder and the mechanical performance of asphalt mixtures, with the highest improvement observed at the 4% SBS content, providing an effective balance between stiffness, deformation resistance, workability, and moisture susceptibility.