Overview
Penetration bitumen is graded by how deep a standard needle sinks into it at 25 °C, in tenths of a millimetre. It is the most widely used paving binder.
In warmer regions, a stiffer bitumen with a lower penetration grade resists heat better. In colder climates, a softer bitumen with a higher grade stays flexible and resists cracking.
Supply comes from six production complexes in Tehran, Tabriz, Arak, Shiraz, Bandar Abbas and Abadan, made to national and international road-construction standards.
Technical data sheet
Penetration grades (ASTM D36-95 / UNI EN 1426)
| Specification | Unit | 10/20 | 30/40 | 35/50 | 40/50 | 50/70 | 60/70 | 80/100 | 85/100 | 100/120 | 160/220 | 200/300 | Test method |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Specific gravity @25°C | — | — | 1.01-1.06 | — | 1.01-1.06 | — | 1.01-1.06 | 1.01-1.05 | 1.01-1.05 | 1.01-1.04 | — | 1.01-1.05 | ASTM D-70 |
| Penetration @25°C, 100 g, 5 s | 0.1 mm | 10-20 | 30-40 | 35-50 | 40-50 | 50-70 | 60-70 | 80-100 | 85-100 | 100-120 | 160-220 | 200-300 | ASTM D-5 |
| Softening point, ring & ball | °C | 58-78 | 55-63 | 50-58 | 52-60 | 46-54 | 49-56 | 45-52 | 45-52 | 42-49 | 35-43 | 34-41 | ASTM D-36 |
| Ductility 25°C after TFOT, min | cm | — | 100 | — | 100 | — | 100 | 100 | 100 | 100 | — | 100 | ASTM D-113 |
| Loss on heating, max | % wt | — | 0.2 | — | 0.2 | — | 0.2 | 0.5 | 0.5 | 0.2 | — | 1.3 | ASTM D-6 |
| Drop in penetration after heating, max | % | — | 20 | — | 20 | — | 20 | 20 | 20 | 20 | — | — | ASTM D-6 & D-5 |
| Flash point, Cleveland open cup, min | °C | — | 250 | 240 | 250 | 230 | 250 | 232 | 232 | 250 | 220 | 177 | ASTM D-92 |
| Solubility in CS₂, min | % wt | — | 99.5 | 99 | 99.5 | 99 | 99.5 | 99.5 | 99.5 | 99.5 | 99 | 99 | ASTM D-4 |
| Organic matter insoluble in CS₂, max | % wt | — | — | — | 0.5 | — | 0.5 | 0.5 | 0.2 | 0.2 | — | 0.5 | ASTM D-4 |
| Spot test | — | — | Negative | — | Negative | — | Negative | Negative | Negative | Negative | Negative | Negative | AASHTO T 102 |
A dash means no value is given for that grade.