Viscosity grade bitumen, (known as VG bitumen), is used in road construction for surface coating applications and the production of hot mix asphalt. The VG specification system was initially introduced in the US during the 1960’s to assess bitumen’s performance at high temperatures. Viscosity grades are specified in the standards ASTM D3381-09 and AASHTO M226-80. For example, bitumen classified AC20 is a bitumen whose viscosity (degree of fluidity) is equal to 2000 Poise at 60°C. Viscosity tests are conducted according to two methods of grading:
– Conventional bitumen (AC-Grades): the viscosity of the standard bitumen is measured at 60°C (140 °F) and 135°C (275 °F)
– Aged bitumen (AR-Grades): the viscosity of bitumen is measured at 60 °C (140 °F) after the Roll on Thin Film Oven Test (RTFOT)
For both methods the penetration at 25°C (annual average pavement temperature) is also retained as a specifications’ criteria. RUBIS ASPHALT MIDDLE EASR / ERES offers a range of AC Grade Bitumen from AC-10 to AC-40. We have also the expertise to manufacture in-house AC grade bitumen for special requests.