Having heard of the Viscosity grade bitumen makes you think,” What is it?” and “What is the viscosity of bitumen?” This type of bitumen or better to say a specific method of bitumen measurement is highly accurate in measuring its hardness in comparison with other forms.

What is viscosity grade bitumen?

Bitumen, a thick, sticky black material derived from crude oil, is essential for modern infrastructure and construction. A notable type is VG bitumen (Viscosity Grade), a petroleum-based material produced from fractional vacuum bottoms during crude oil distillation.

Viscosity Grade bitumen is primarily used as a paving-grade bitumen for road construction. While traditional paving bitumen was specified based on penetration tests, viscosity measurement offers a more precise way to determine binder consistency and assess temperature susceptibility.

This makes viscosity grade bitumen a better choice for specifying bitumen properties. VG bitumen is specifically designed to meet the diverse needs of applications like road construction, asphalt pavement production, roofing, and various industrial processes.

Viscosity grade bitumen is thermoplastic, softening at high temperatures and hardening at low temperatures. This relationship impacts adhesion, rheology, durability, and application temperatures. Ductility, the ability to deform without breaking, is also a key factor in its specifications.

Formula of viscosity grade bitumen

Since Bitumen does not have a fixed formula, there are different formulas based on its needs. So, this product such as viscosity grade bitumen, is a complex mixture of hydrocarbons.

Each bitumen product has a unique composition, containing various numbers of molecules. While bitumen is primarily composed of carbon and hydrogen, it also contains smaller amounts of oxygen, nitrogen, and sulfur.

Note that the composition of viscosity grade bitumen plays a crucial role in determining its physical properties. Any difference in the components and manufacturing processes, impacts the balance and characteristics of the bitumen, affecting its performance in different applications.

Component	Description	Function
Saturants	Stable, linear hydrocarbons.	Provide stability and uniformity.
Aromatics	Flat chain hydrocarbons.	Enhance resilience and deformation recovery.
Resins	Flat, polar hydrocarbons.	Improve adhesive properties, aiding in aggregate binding.
Asphaltenes	Dense, heavy molecular weight hydrocarbons with sulfur, nitrogen, and oxygen.	Increase hardness and durability.

viscosity grade bitumen methods of grading and types

Viscosity Grade Bitumen is categorized based on its flow characteristics at different temperatures which is based on different methods of grading. Its grading is determined through tests at:

• 60°C: To measure high-temperature viscosity.
• 135°C: To assess workability during mixing and compaction.

These tests ensure the bitumen’s suitability for various climatic and construction conditions. Moreover, these tests introduce each grade of bitumen based on viscosity.

VG bitumen methods of grading

Viscosity grade bitumen is classified based on standards such as IS 73, ASTM, and AASHTO. Selecting the right viscosity-grade bitumen is essential for road construction and maintenance, ensuring optimal performance based on environmental and traffic conditions.

Now this question is raised, “What is viscosity grade of bitumen?” Grading methods for viscosity-grade bitumen include Standard Viscosity Grade Bitumen (AC-Grades), where viscosity is measured at 60°C on the original (as-supplied) asphalt binder samples.

In contrast, RTFOT Viscosity Grade Bitumen (AR-Grades) involves measuring viscosity at 60°C after the Roll-On Thin Film Oven Test (RTFOT) on aged residue samples, which simulates the effects of the HMA manufacturing process.

AC Grading

• AC-2.5 to AC-40 represent viscosity levels at 60°C, ranging from 250 to 4000 poises.
• Lower viscosity (AC-2.5, AC-5) suits cold climates, while higher viscosity (AC-10 to AC-40) is ideal for hot climates.
• AC grading measures asphalt binder before HMA production.

AR Grading

• AR grading simulates binder behavior after HMA production for a more accurate pavement performance prediction.

VG bitumen types

Knowing how to choose different grades of viscosity grade of bitumen is crucial for road construction and maintenance, as it is categorized by its viscosity at 60°C, determining its consistency and suitability for different conditions. The most common types of viscosity grade bitumen are:

VG10

Best for colder climates, offering flexibility at low temperatures.

VG20

Suitable for standard road projects in moderate climates.

VG30

Ideal for hot climates, providing stability under heavy traffic.

VG40

Designed for very hot climates and heavy-duty roads, with the highest viscosity.

Viscosity grade bitumen uses

Although the viscosity of bitumen grade 60/70 made this bitumen to be used in asphalt mixes, bitumen emulsion, and modified bitumen, Viscosity grade bitumen is also essential in road construction, paving, and surface dressing, offering superior durability and performance in various climates.

Since this product is mostly used in construction, it is useful to know which viscosity of bitumen is recommended for bituminous concrete.

Each viscosity grade is optimized for specific climate and traffic conditions, ensuring the longevity and durability of infrastructure. Different grades are tailored for specific conditions:

VG-10

Ideal for very cold climates, VG-10 is used in surface dressing and paving, replacing 80/100 penetration grade bitumen. It is also used in bitumen emulsion and modified bitumen production. It performs well in temperatures below 30°C, with a viscosity of 800.

VG-20

Suitable for cold climates and high-altitude regions, VG-20 is commonly used in paving applications where the average temperature ranges between 30–37°C.

VG-30

Perfect for heavy-duty pavements that must withstand significant traffic loads, VG-30 replaces 60/70 penetration grade bitumen. It is ideal for temperate climates, wet conditions, and clayed soil.

VG-40

Designed for high-stress areas like intersections, toll booths, and truck parking lots, VG-40 is highly resistant to heavy traffic and high temperatures (above 40°C). With a viscosity of 3200, it is ideal for roads under substantial traffic pressure.

Viscosity grade bitumen vs. penetration grade bitumen

While both PG and VG bitumen are effective in their respective applications, the choice between the two depends on specific project requirements, climate conditions, and available resources.

Viscosity grade bitumen is more cost-effective and widely used for general purposes, while PG Bitumen provides tailored performance for demanding conditions. Here is the chart that shows the difference between penetration grade and viscosity grade bitumen.

feature	Penetration Grade	Viscosity Grade
Grading Method	Needle penetration depth	Flow properties at specific temperatures
Climate Performance	Suitable for moderate climates	Consistent in hot and cold climates
Common Uses	General road construction	High-performance applications
Cost & Simplicity	Cost-effective, easier to test	More expensive, requires more testing
High-Temperature Performance	Suitable, but not tested for extreme heat	Tested for maximum temperature resistance
Low-Temperature Performance	Not tested for low temperatures	Tested for cold weather resistance
Customization	Less specific for varying conditions	Tailored for specific traffic and climate needs
Global Usage	Mainly in India and select countries	Widely used worldwide

Why Kiapetro?

The price of VG bitumen is heavily influenced by international economic conditions. During periods of economic growth, demand for infrastructure projects rises, which in turn increases the demand for this product, leading to higher prices.

At Kiapetro, we offer high-quality viscosity grade bitumen with competitive pricing and flexible payment options. Our products adhere to international standards, ensuring consistent performance and reliability.

Kiapetro produces and provides all types of viscosity grade bitumen such as VG10, VG20, VG30, and VG40 in high quality. We prioritize timely delivery and excellent value, catering to both one-time and recurring orders with tailored solutions to meet the unique needs of our clients.

FAQ

1. VG30 or VG40? Which one is better?

VG40 is better for high-temperature areas.

2. Which VG types are harder?

VG40 is the hardest and VG10 is the least hard.

3. What is the difference between VG and PG bitumen?

PG is penetration at 25°C, VG is at 60°C and 135°C.