Viscosity Grade Bitumen Description
Viscosity Grade Bitumen (VG Bitumen) is a type of bitumen introduced in the late 20th century by the United States. It is graded based on viscosity at 60°C and 135°C, with penetration at 25°C also measured. This test helps understand bitumen’s response to temperature fluctuations, demonstrating its resistance to flow in hot climate conditions. VG bitumen is most commonly used in India, with four grades: VG10, VG20, VG30, and VG40. The viscosity test offers a more fundamental approach to analyzing bitumen’s behavior in specific temperatures.
Type of Viscosity Grade Bitumen
- VG 10 Bitumen is the softest grade of viscosity bitumen, suitable for spraying applications and surface coating in cold climates. It is also used for manufacturing bitumen emulsions and modified bitumen products, particularly in India. VG10 has better performance in cold weather due to its viscosity.
- VG 20 Bitumen is suitable for cold climatic and high altitude regions, suitable for road construction in regions with 30 to 37°C average temperatures.
- VG 30 Bitumen is primarily used for extra-heavy bitumen pavements that bear significant traffic loads. VG30 can be used instead of 60/70 penetration bitumen grade.
- VG 40 Bitumen is used in areas with high pressure from heavy traffic loads, such as intersections, near toll booths, and truck parking lots. Its high viscosity makes it suitable for improving resistance to shoving and other problems associated with higher temperatures and heavy traffic loads. VG40 has been used in industries for a long time instead of the penetration grade bitumen 40/50.
VG Bitumen Application
Viscosity Grade Bitumen (Asphalt) is a standard grade bitumen used in road construction and asphalt pavement production. It is primarily used in hot mix asphalt for bases and wearing courses and has unique characteristics and qualities.
Viscosity Grade Bitumen achieves flexible and tenacious connections with other materials due to its viscoelastic response, which depends on the speed of charges applied. It is petroleum grade bitumen, manufactured from fractional/vacuum distillation of crude oil, and is specified by ASTM Standard D3381–09 and AASHTO M226-80 (2008).
Viscosity Graded specifications cover bitumen graded by Viscosity at 60 C (140 °F). Higher grades stiffen the bitumen. Tests are conducted at 60 C and 135 C, representing the temperature of road surface during summer and mixing temperature, respectively.
Comparison Standards of VG Bitumen
Standard Absolute and Kinematic Viscosity
For measuring the viscosity of bitumen, there are two methods known as absolute (or dynamic) viscosity and kinematic viscosity.
In absolute viscosity, the level of bitumen’s resistance to flow is measured in 60° C, but kinematic viscosity is the viscosity to density ratio in 135° C.
The difference between these two types of viscosity grading is that the absolute viscosity predicts the characteristics of bitumen in a hot summers, but the kinematic viscosity predicts the bitumen performance in a hot mix asphalt.
These grading test results are VG10, VG20, VG30, and VG40 that are more popular in Asian and African countries.
Specification
| Specification | VG-10 | VG-20 | VG-30 | VG-40 |
|---|---|---|---|---|
| Absolute Viscosity 60 ◦C, Poises, min | 800 | 1600 | 2400 | 3200 |
| Kinematic Viscosity, 135 ◦C, CST, min | 250 | 300 | 350 | 400 |
| Flash Point, ◦C, min | 220 | 220 | 220 | 220 |
| Solubility in Trichloroethylene, %, min | 99 | 99 | 99 | 99 |
| Penetration Value, at 25 ◦C | 80-100 | 60 | 50-70 | 40-60 |
| Softening Point, ◦C, min | 40 | 45 | 47 | 25 |
| Thin-Film Oven Test (TFOT) | ||||
| Viscosity Ratio at 60 ◦C, Max | 4 | 4 | 4 | 4 |
| Ductility at 25 ◦C, Cm, Min | 75 | 50 | 40 | 25 |
| Specific Gravity at 25 ◦C | – | – | 1.0131 | – |
