Bitumen Viscosity Grade

What is Viscosity Grade bitumen?

Viscosity grades Bitumen are categorized according to Viscosity (degree of Fluidity) grading. The higher the grade, the stiffer the Bitumen. In Viscosity Grade, Viscosity tests are conducted at 60 deg. C and 135 deg. C, which represents the temperature of road surface during summer and mixing temperature respectively. The penetration at 25 deg. C, which is annual average pavement temperature, has been also retained in Specifications.

The new method of grading the product has now rested on the viscosity of the bitumen (at 60 C and 135 deg. C). The new grades have thus evolved with nomenclature:

Grades Minimum of Absolute
viscosity, Poise@ 600C
penetration grade
VG10 800 80-100
VG20 1600 —–
VG30 2400 60-70
VG40 3200 30-40/40-50

IS 73:2006 has been released by Bureau of Indian Standards. Three grades of bitumen confirming to IS 73: 1992 are manufactured in India. In this third revision grading of Bitumen is changed from penetration grade to viscosity grade. To improve the quality of Bitumen, BIS revised IS-73-1992 Specifications based on viscosity grade (viscosity @ 60 deg. C) in July 2006.

As per the Specifications, there are four grades VG-10, VG-20, VG-30 & VG-40.

  • Bulk
  • Drum 180, 150, 200 KG (0.6 mm Thickness )
  • Jumbo bag (1 MTon)
  • Poly bag


    • VG-10 BITUMEN

      VG-10 is mostly used in spraying applications such as surface dressing and Paving in very cold climate instead of 80/100 penetration bitumen grade. It is also used to produce Bitumen Emulsion and Modified Bitumen products.

    • VG-20 BITUMEN

      VG-20 is used for paving in cold climate & high altitude regions.

    • VG-30 BITUMEN

      VG-30 is especially used to construct extra heavy duty Bitumen pavements that need to tolerate significant traffic loads. It can be used instead of 60/70 penetration bitumen grade.

    • VG-40 BITUMEN

      VG-40 is used in highly stressed areas such as intersections, near toll booths and truck parking lots instead of 30/40 penetration grade. Because of higher viscosity, stiffer Bitumen mixes can be produced to amend resistance to shoving and other problems related to higher temperature and heavy traffic loads