Viscosity Grade Bitumen
Performance-Based Specifications
Viscosity Grade Bitumen (VG Bitumen) is classified based on its viscosity (flow resistance) at 60∘C and 135∘C Unlike the Penetration Grade, which only measures consistency at a single temperature, the VG system provides a more accurate performance prediction for the binder throughout its service life in varying temperatures. This system is favored in many regions for its emphasis on rheological properties.
Key Features & Applications :
Definition
Classified by its viscosity at 60∘C (e.g., VG-30, VG-40).
Primary Us
Hot Mix Asphalt (HMA) applications where consistent performance is critical.
Benefit
Better resistance to rutting at high temperatures (due to specified viscosity).
Suitability
Excellent for high-volume traffic areas and projects requiring stringent material control.



