Viscosity Grade Bitumen which is produced during the process of oxidation of vacuum bottom in distillation tower and is categorized based on absolute viscosity at 60 ºC or kinematic viscosity at 135 ºC. There are four grades VG-10, VG-20, VG-30 & VG-40. The main common usage of VG is in road construction, water proofing, building construction industries and also in cutback bitumen production.