The most common grade of BITUMEN is 60/70 which is applicable in road construction and asphalt pavements. Today the world’s demand for BITUMEN accounts for more than 100 million tons per year which is approximately 700 million barrels of BITUMEN consumed annually.
Petroleum BITUMEN is typically referred to as bitumen or asphalt. In Europe for instance BITUMEN means the liquid binder. In North America, on the other hand, the liquid binder is referred to as asphalt or asphalt cement.
BITUMEN occurs in nature in several forms: hard one – easily crumbled BITUMEN in rock asphalt and softer, more viscous material which is present in tar sands and asphalt ‘lakes’. Another way in which BITUMEN can be obtained is through petroleum processing in this manner the BITUMEN is essentially the residue yielded through a distillation process of petroleum. Although BITUMEN can be found in natural form, the world currently relies for all purposes on petroleum. The material has been produced in this way for over a hundred years.
Depending on physical properties, there are various types of BITUMEN based on penetration as follows:
BITUMEN Penetration Grade 30/40
BITUMEN Penetration Grade 40/50
BITUMEN Penetration Grade 50/70
BITUMEN Penetration Grade 60/70
BITUMEN Penetration Grade 85/100
BITUMEN Penetration Grade 100/120
In this case, the unit of penetration is dmm (deci-millimeter) means 1/10 of a millimeter. As an example, 65 dmm means 6.5 millimeters is the penetration amount of the noodle in the sample and its grade would be 60/70. Obviously, the most penetration value is related to the least viscose sample and
| Test Name | Unit | Standard | Test Method |
| Penetration @25 °C | dmm | 60-70 | ASTM D5 |
| Specific gravity @25 °C | - | 1.01-1.06 | ASTM D7 |
| Ductility @25 °C | cm | >100 | ASTM D113 |
| Viscosity @135 °C | CST | - | ASTM D4402 |
| Viscosity @60 °C | poise | - | ASTM D4402 |
| Flash point | °C | >240 | ASTM D92 |
| Softening point | °C | >46 | ASTM D36 |
| Solubility in toluene | % | 99.5min | ASTM D4 |
| Spot test | | negative | AASHTO T102 |
| Loss on heating | % | 0.2 max | ASTM D6 |
| Retained Penetration | % | >55 | ASTM D5 |
| Retained Ductility@25 °C | cm | >50 | ASTM D113 |
| No. | Analysis | Unit | Limit | Test Method |
|---|---|---|---|---|
| 1 | Density@25°C | Kg/m3 | 1010-1060 | ASTM D70 or D3289 |
| 2 | Penetration @25 °C | Mm/10 | 50-70 | ASTM D5 |
| 3 | Softening point | °C | 46 Min. | ASTM D36 |
| 4 | Ductility@25°C | Cm | 100 Min. | ASTM D113 |
| 5 | Loss on heating | Wt% | 0.2 Max. | ASTM D6 |
| 6 | Drop in penetration after heating | % | 20 Max. | ASTM D5 and D6 |
| 7 | Flash point | °C | 232 Min. | ASTM D92 |
| 8 | Solubility in Trichloroethylene | Wt% | 99.0 Min. | ASTM D4 |
| 9 | Spot test | – | Negative | AASHOT102 |
| 10 | Viscosity@60°C | P | 2000+400 | ASTM D2171 |
| 11 | Viscosity@135°C | CST | 300 Min. | ASTM D2170 |
- In the third revision of Bureau of Indian Standard (IS 73:2013), grading of bitumen was changed from penetration grade to viscosity grade.
- Viscosity Grade (VG) Bitumen is a Bitumen grade mostly used as a Paving Grade and it’s suitable for road construction and for asphalt pavements producing premier attributes.
- Viscosity grade bitumen has a thermoplastic feature that causes the material to soften at high temperatures and harden at lower temperatures. This temperature viscosity relevance is significant when specifying the performance parameters such as the adhesion, rheology, durability, and application temperatures of bitumen. In the Viscosity Grade Bitumen specifications, the most important emphasis is based on the Bitumen ductility.
- Low viscosity grades VG-10 and VG-20 are used in cold climates while high viscosity grades VG-30 to VG-40 are generally suitable for hot climates.
- Viscosity Grade Bitumen shall conform to the standard limits as per the below table:
| Characteristics | VG-10 | VG-20 | VG-30 | VG-40 |
|---|---|---|---|---|
| Absolute viscosity, 60 °C, poises, min | 800-1200 | 1600-2400 | 2400-3600 | 3200-4800 |
| Kinematic viscosity, 135 °C, CST, min | 250 | 300 | 350 | 400 |
| Flashpoint, °C, min | 220 | 220 | 220 | 220 |
| Solubility in trichloroethylene, %, min | 99.0 | 99.0 | 99.0 | 99.0 |
| Penetration at 25 °C, min | 80 | 60 | 45 | 35 |
| Softening point, °C, min | 40 | 45 | 47 | 50 |
| Tests on residue from thin film oven test/RTFOT: | ||||
| Viscosity ratio at 60 °C, max | 4.0 | 4.0 | 4.0 | 4.0 |
| Ductility at 25 °C, cm, min, after thin film oven test | 75 | 50 | 40 | 25 |