Paving Grade Bitumen
Grade 60/70 and 30/40
Straight grade used in construction and maintenance of roads, airfields and allied constructions, manufacturing of bitumen Emulsions.
Bitumen is the end product in the crude distillation process. This raw bitumen is called Straight grade bitumen and has penetration values of 200-300. The straight grade bitumen obtained from the refineries is processed in our highly modernized plant through the exothermic reaction, to the relevant time limit to produce the desired Paving Grades as per the specifications.
Viscosity Grade bitumen is designed to take care of lowest temperature(responsible for cracking) and maximum temperature(responsible for rutting).
Benefits / Advantages of VG Bitumen over Penetration grade:
VG system is based on fundamental engineering parameter(not empirical).
Viscosity is measured at 60degree C and 135degree C, which takes care of both low and high-temperature susceptibility of the binder, which is not possible with penetration value at 25degreeC. Hence pavement engineers, contractors/consultants can have a better understanding of the binder’s performance in the field.
Any two same viscosity grade bitumens would give similar rutting performance in the field.
Greater ease of handling to customers as Viscosity Value at two different temperatures(60degreeC and 135degree C) is available, which would enable users to measure accurate mixing and compaction temperatures.
Minimum specified Kinematic Viscosity value at 135degree C helps to minimize the potential of tender mixes during construction.
Viscosity graded bitumens are suitable for a wide range of temperature: 25degreeC for raveling/fatigue cracking. 60degreeC for rutting and 135degreeC for construction(mixing and compaction).
IS 73-2006 has only 7 tests to evaluate a sample compared to 14 tests in penetration grade system. This reduces time and cost of testing without sacrificing its quality.