viscosity grade

Viscosity Grade Bitumen

Viscosity Grade Bitumen or VG:

Viscosity grade bitumen is a fundamental property that determines how the material behaves at a certain temperature or a temperature range. The main unit of viscosity is pascal’s second (Pa s). The absolute viscosity or bitumen dynamics measured in pascal seconds is the shear stress applied to the sample in pascals divided by the shear rate per second (1 Pa = 10 Poise). The absolute viscosity of bitumen can be measured by a sliding plate viscometer. For many purposes, it is common to determine bitumen viscosity by measuring the time required for a given amount of material to pass through a standard orifice. These methods are suitable for determining and comparing; if needed, the results can be converted to more fundamental viscosity units.

Applications for viscosity bitumen:

The viscosity class of bitumen is called a grade of refinery bitumen obtained from the vacuum aeration of the distillation tower and divided according to their viscosity. The most common use of this type of bitumen is in road construction, insulation, building construction, and
liquid bitumen production. In terms of place of use, VG30 bitumen is more suitable for temperate climates.

Classification for Viscosity grade bitumen:

viscosity grade test is measured at 60 and 135, which is the 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 the average annual temperature of the asphalt coating is also specified in the specifications of this bitumen standard. The category of viscosity grade of bitumen is classified based on the
viscosity test results. This category of bitumen, which has many uses in hot areas, will soon replace penetrating bitumen.

Different types of viscosity grade bitumen:

The viscosity grade of bitumen is a kind of standard bitumen that is suitable for paving stone, road construction, and asphalt production with special characteristics. Due to its elastic properties, it is used for very strong and flexible connections. As a producer and supplier of different viscosity grades of bitumen, Grand petroleum Company is ready to cooperate and provide your requests for sale in the domestic and foreign markets (exports).

Note: AC bitumen is Asphalt cement solid whose abbreviation is AC, which is obtained from the distillation of crude oil.

  • Bitumen AC-2.5

Bitumen AC-2.5 is asphalt cement with a viscosity of 250 poises at 60c. viscosity grade of bitumen AC-2.5 is the softest grade among all of
the bitumen. Bitumen AC-2.5 is known to the low viscosity, soft bitumen mixtures can’t be produced to improve resistance to displacement and other problems associated with high temperatures and heavy traffic loads.

  • Bitumen AC-5

Bitumen AC5 is a kind of bituminous asphalt, because of its low viscosity this grade of bitumen is mostly used in cold regions. This asphalt is suitable for cold countries like Canada. The temperatures of storage for AC5 are preferred at 135°C to 163°C. High temperatures can increase hardening and heating costs. Bitumen AC5 is suitable to be used for road construction in cold climates. Also, Bitumen AC5 is suitable for manufacturing asphalt mixes, emulsion for some grades of bitumen, modified bitumen, and cut-
back bitumen.

Availability and Ordering:

Grand petroleum Company Bitumen Penetration Grade AC is available in  different packages ready to meet domestic and international market demands.

  • Stainless steel drum
  • Bulk
  • Jumbo Bag
  • Flexi Tanks

To inquire about the latest pricing or to initiate an order, Contact Grand Petroleum Sales

  • Bitumen AC-10

Bitumen AC10 is the result of the heaviest cut of crude oil. The most common application of this elastic compound is related to the
the construction industry, the production of moisture insulation, the production of some chemical compounds and most importantly, the road construction industry. Also, the combination of bitumen AC10 with sand is called asphalt to repair, renovate, and establish roads. Intra-city and inter-city routes are used.

  • Bitumen AC-20

Bitumen AC20 is been categorized according to Viscosity (degree of fluidity) grading. In other words, The higher the grade, the stiffer the
Bitumen AC20is a kind of standard bitumen that is suitable for paving stone, road construction, and asphalt production with special
characteristics. Due to its elastic properties, it is used for very strong and flexible connections.

  • Bitumen AC-30

Bitumen AC 30 is a grade of Viscosity for Bitumen that this Viscosity of the standard bitumen (asphalt) is measured at 60 degrees. The main
usage of bitumen AC 30 is in road making in hot temperate regions. The applications of bitumen AC 30 are suitable for road construction
projects in warm & dry regions. Also, it can be useful for producing some kind of asphalt primer. Bitumen AC 30 is used in road construction, surfacing, and some industrial applications and manufacture asphalt mixes, bitumen emulsion, cut-back bitumen, and modified bitumen.

  • Bitumen AC-40

Bitumen AC40 is suitable for the construction of sidewalks and asphalt in tropical areas such as tropical belts in India or even in the south of
our country, Iran; It should be considered when buying bitumen. Since bitumen AC40 has high stability in hot weather, it has received special attention for the repair or construction of roads and sidewalks in tropical areas where the average air temperature is high.
Also, the versatility of Bitumen AC40 to be used in hot mix asphalt has made the demand for this product and the purch

viscosity grade bitumen

Viscosity stands as a pivotal technological and functional parameter within the realm of bituminous binders. Various definitions and test methods underscore its importance. In the context of bitumen, viscosity embodies the internal friction encountered as particles shift between layers.

Bitumens, akin to liquids, possess intricate rheological traits. Their viscosity fluctuates in response to temperature, shear rate, test duration, and the methodological nuances employed. Thus, ensuring the comparability of viscosity results mandates adherence to meticulously defined measurement conditions: appropriate temperature, calibrated measuring systems, consistent shear rates, and standardized testing durations.

Deviation from these conditions may render comparisons and substitutions of viscosity results erroneous, potentially yielding misleading conclusions. Notably, the inverse relationship between bitumen temperature and viscosity underscores its utility in establishing viscosity-temperature characteristics, vital for determining pumping temperatures, aggregate coating, and pavement compaction.

Yet, caution must be exercised, particularly with polymer modified bitumen and highly modified bitumen HiMA, whose unique properties stemming from polymer compositions render conventional viscosity-temperature relations inadequate for precise temperature determinations. In such cases, temperatures derived from these relations should be viewed as approximate, reflecting the complexity of the materials involved.


Imagine a road basking under the summer sun, its surface firm yet flexible. This remarkable characteristic is largely thanks to a hidden hero: bitumen. But what exactly is bitumen, and how does its viscosity play such a crucial role in road construction?

Think of bitumen as the black glue that holds everything together. It’s a complex liquid with a personality all its own, and one of its defining features is its resistance to flow, which we call viscosity. Just like honey thickens in the fridge and thins when warmed, bitumen’s viscosity changes with temperature. The hotter it gets, the more easily it flows.

This temperature sensitivity is crucial. When constructing roads, we need bitumen that’s flexible enough in cold weather to withstand cracks, yet firm enough in hot weather to prevent ruts from forming under heavy traffic.

Here’s where Viscosity Grade  Bitumen comes in. It’s specially graded based on its viscosity, like a spectrum from thin and runny (VG10) to thick and sluggish (VG40). Choosing the right grade for the job is essential. Imagine using honey for road construction in the summer – it would be a sticky mess!

But bitumen is more than just a temperature-sensitive glue. It also boasts impressive adhesion, clinging tightly to the stones (aggregates) used in asphalt mixes. This keeps our roads strong and prevents them from crumbling under pressure.

Furthermore, bitumen is durable, standing up to harsh weather and the constant wear and tear of traffic. It’s even water-resistant, protecting the road base from water damage, which can be a major enemy of asphalt.

And don’t forget its elasticity. Just like a rubber band, bitumen can stretch and return to its original shape, allowing it to absorb the impact of vehicles without cracking.

So, the next time you drive on a smooth, resilient road, remember the silent hero beneath your tires – bitumen. It’s a fascinating material, and understanding its viscosity and other properties is key to building roads that are built to last.









Viscosity at 60° C







Viscosity at 135° C







Penetration at 25° C, 100 grams, Five Seconds







Flash point, Cleveland Open Cup







Solubility in Trichloroethylene







Test on the Residue of Thin Bitumen Layer

Heating Loss






Viscosity at 60° C







Ductility at 25° C, 5cm/min







Stain Test

Naphtha Solvent


Naphtha-Xylene Savent, Xylene Percentage


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