Viscosity Grade Bitumen
Viscosity bitumen and VG bitumen ratings
Viscosity bitumen is a type of bitumen that is classified according to its viscosity. The viscosity of a substance is its resistance to flow. Viscosity bitumen is used in making asphalt, insulation and other applications.
Bitumen viscosity is classified according to two main gradations:
ASTM classification: This classification is classified based on the time required for the flow of a certain amount of bitumen at temperatures of 60 and 135 degrees Celsius.
AASHTO Grading: This grading is classified based on the time required for a given amount of bitumen to flow at 25°C.
Grading bitumen viscosity
Bitumen viscosity is classified according to two main gradations:
Bitumen viscosity is measured using a device called a viscometer. A viscometer is a long, narrow tube with a bitumen tank at one end. The bitumen tank is closed with a piston on top. To measure viscosity, the piston is slowly lowered and the time required for a certain amount of bitumen to flow through the tube is measured.
ASTM classification: This classification is classified based on the time required for the flow of a certain amount of bitumen at temperatures of 60 and 135 degrees Celsius.
AASHTO Grading: This grading is classified based on the time required for a given amount of bitumen to flow at 25°C.
ASTM grading
In ASTM grading, viscosity is indicated using one letter and two numbers. The letter indicates the ASTM rating, and the first number indicates the time required for the bitumen to flow at 60°C and the second number indicates the time required for the bitumen to flow at 135°C.
For example, VG-100 bitumen is classified using the ASTM grading and has a flow time of 100 seconds at 60°C and a flow time of 100 seconds at 135°C.
AASHTO grading
In AASHTO grading, viscosity is indicated using a letter and a number. The letter indicates the AASHTO rating and the number indicates the time required for bitumen to flow at 25°C.
For example, VG-20 bitumen is classified using the AASHTO grading and has a flow time of 20 seconds at 25°C.
The relationship between bitumen viscosity grades
A higher grade bitumen has more viscosity and flows more slowly. Lower grade bitumen has lower viscosity and flows faster.
In general, higher grade viscosity bitumen is used in applications that require higher viscosity bitumen, such as asphalt construction. A lower grade viscosity bitumen is typically used in applications that require a higher flow ability bitumen, such as insulation.
The classification of bitumen viscosity is classified based on the time required for the flow of a certain amount of bitumen at a temperature of 60 degrees Celsius.
The VG10, VG20 and VG30 ratings indicate the time required for bitumen to flow at 60°C. In other words, VG10 bitumen flows in 10 seconds at 60°C, VG20 bitumen flows in 20 seconds, and VG30 bitumen flows in 30 seconds.
This classification is simple and easy to understand. Also, this classification is widely accepted in the oil and petrochemical industry.
In some cases, other classifications may be used for bitumen viscosity. For example, in the United States, the AASHTO classification is used. This classification is based on the time required to flow a certain amount of bitumen at a temperature of 25 degrees Celsius.
However, VG10, VG20 and VG30 are the most commonly used bitumen viscosity ratings.
Viscosity grade bitumen (VG)
The higher the temperature, the harder the bitumen is. In the viscosity grade, the viscosity test is measured at 60 and 135, which is the temperature of the road surface in summer and the temperature of mixing asphalt, respectively.
The degree of penetration at a temperature of 25 degrees, which is the average annual temperature of the asphalt coating, is also specified in the specifications of this bitumen standard.
Viscosity category bitumen are classified based on the viscosity test results. This category of bitumen, which has many uses in areas like India, will soon replace penetrating bitumen in these areas.
Bitumen VG-10
Bitumen VG-20
Bitumen VG-30
Bitumen VG-40
