The vast majority of bitumen used in asphalt for road construction is bitumen 60/70. This grade’s full name is bitumen penetration grade 60/70 and is one of the most widely used grade of bitumen across the world.
Bitumen 60/70, which is also called the paving grade bitumen, works well in almost every application. Since this grade of bitumen is suitable for road construction in a wide range of temperatures (from -22 to +76).
Continue reading to find out more details about bitumen pen grades production, specifications, and applications.
What is the Meaning of Bitumen Grade 60/70?
To understand bitumen 60/70 grade meaning, we need to pay attention to the way this type of bitumen is tested after production. This grade of bitumen is named after the penetration test on bitumen.
In this method of testing, we penetrate a standard needle in a sample of bitumen and measure the speed of penetration and estimated the bitumen’s hardness.
With this method of testing, we classify ordinary bitumen into more than 5 grades, including:
- bitumen 30/40
- bitumen 40/50
- bitumen 60/70
- bitumen 80/100
- bitumen 100/120
As you can see in the above range, bitumen 60/70 is a moderate type of penetration grade bitumen. In bitumen 60/70 the numbers 60 and 70 mean that the penetration value of bitumen is between 60 and 70 mm.
Bitumen 60/70 Specifications
The quality of bitumen 60/70 depends on its physical properties and specifications which are obtained by applying bitumen tests. Apart from the penetration test, there are a number of tests that are used for specifying bitumen 60/70 including
Some of these items are more important for suppliers of bitumen 60/70 and their customers. These are softening point and flashpoint values. According to the ASTM D36 method, the softening point of bitumen 60/70 is between 49 to 56 °C, and the flash point of bitumen 60/70 is 250 °C. Another important factor is density. Due to the ASTM D70, the density of bitumen 60/70 is equal to 1.0344.
For more details on bitumen 60/70 specifications, see the table:
| Bitumen Penetration Grade 60/70 Specifications | ||||
|---|---|---|---|---|
| Specification | Test Method | Unit | Min. | Max. |
| Specific Gravity at 25 °C | ASTM D70 | kg/m³ | 1.01 | 1.06 |
| Penetration at 25 °C, 100g, 5s | ASTM D5 | 0.1mm | 60 | 70 |
| Softening Point | ASTM D36 | °C | 49 | 56 |
| Ductility at 25 °C | ASTM D113 | Cm | 100 | – |
| Loss on Heating | ASTM D6 | %WT | – | 0.2 |
| Drop in Penetration after Heating | ASTM D5 | % | – | 20 |
| Flash Point | ASTM D92 | °C | 250 | – |
| Solubility in Trichloroethylene | ASTM D2042 | %WT | 99 | – |
| Spot Test | AASHTO T102 | Negative | ||
The Difference between Bitumen 60/70 and 80/100
The main difference between 60/70 and 80/100 is their penetration value.
To decide between 60/70 vs bitumen 80/100, we should consider the fact that bitumen penetration 80/100 is softer than bitumen 60/70. For this reason, bitumen 80/100 is used at cold temperatures.
Find out more information about bitumen 80/100.
What are Bitumen 60/70 Uses?
The vast majority of bitumen used in asphalt for road construction is bitumen 60/70; that is why this type of bitumen is known as paving grade.
In road projects across the world, they blend this grade of bitumen with aggregates to form hot mix asphalt and pave the road.
Bitumen 60/70 is a popular grade in India and South East African countries since its quality is acceptable and price is not too high.
By extending the performance of final asphalt and treating the cracks in the time of maintenance, bitumen 60/70 is known as a cost-effective solution that reduces the expenses without affecting the quality.
Another application of bitumen 60/70 is in the production of polymer modified bitumen. In PMBs production, we add certain polymers to bitumen 60/70 to improve its properties, including elasticity, brittle point, and the softening point, which are essential for the better performance of asphalt mixture.
How is Bitumen 60/70 Produced?
Bitumen 60/70 is usually produced from crude petroleum oil. Just like other penetration grades, this grade is produced through a blowing process in a refinery.
Due to its medium air blowing and penetration, this grade of bitumen is not too soft or hard.
Bitumen 60/70 does not need further processing, unlike other grades of bitumen. In the industry, this type of bitumen is also named straight run, which means this type of bitumen is produced direct from the vacuum distillation process.
Since this bitumen does not require any modifications, bitumen 60/70 price is lower than other grades of bitumen.
Click to learn about the production process of bitumen.
