Asphalt cement, or AC grade bitumen, is one of the most common types of viscosity grade bitumen. Viscosity grade bitumen is divided into two groups by the American Association of State Highway Officials (AASHTO):
- Asphalt Cement (AC) Grade Bitumen
- Aged Residue (AR) Grade Bitumen
AC bitumen is classified into several grades, and they can be used in different temperature conditions and traffic loads.
Continue reading to get more information about AC grade bitumen.
Difference Between AC Grade Bitumen vs AR Grade Bitumen
The meaning of the numbers that come after AR and AC grades is different. The number after the AC grade shows the viscosity at 60 °C, while the number after the AR grade gives the viscosity at 60 °C in the thin film oven test.
What are AC 10, AC 20, and AC 30 Bitumen?
AC10, AC20, and AC30 are three popular grades of AC bitumen, sometimes known as AC10 asphalt, AC20 asphalt, and AC30 asphalt.
The AC grading is based on absolute viscosity at 60 °C in 100 poises. It means the viscosity of bitumen AC10 is equal to 10*100 or 1000 poise (100 Pa.s).
AC10 Asphalt
Bitumen AC 10 or AC10 asphalt is a kind of low viscosity grade of AC bitumen. It has relatively high penetration and ductility values. Bitumen AC 10 is typically utilized in places with lower temperatures or for the construction of roadways with light traffic.
The table below contains the AC10 asphalt specifications:
| Bitumen AC10 Specification | |||
| Specification | Test Method | Unit | Value |
| Viscosity, @ 60 °C | ASTM D2171 | Poise (10*Pa.s) | 1000±200 |
| Viscosity, @ 135 °C | ASTM D2170 | CST | Min 150 |
| Flash Point (Cleveland Open Cup) | ASTM D92 | °C | Min 219 |
| Solubility in Trichloroethylene | ASTM D2042 | %WT | Min 99 |
| Penetration, 100g, 5s, @ 25 °C | ASTM D5 | 0.1mm | Min 70 |
| Thin-Film Oven Test (TFOT) | |||
| Viscosity, @ 60 °C | ASTM D2171 | Poise (10*Pa.s) | Max 5000 |
| Ductility, 5 cm/min, @ 25 °C | ASTM D113 | cm | Min 50 |
AC20 Asphalt
Bitumen AC 20 is suitable for moderate temperature and traffic load. It is harder than AC 10 and softer than AC 30.
The following table indicates the Bitumen AC 20 specification:
| Bitumen AC20 Specification | |||
|---|---|---|---|
| Specification | Test Method | Unit | Value |
| Viscosity, @ 60 ◦C | ASTM D2171 | Poise (10*Pa.s) |
2000±400 |
| Viscosity, @ 135 ◦C | ASTM D2170 | CST | Min 210 |
| Flash Point (Cleveland Open Cup) | ASTM D92 | ◦C | Min 232 |
| Solubility in Trichloroethylene | ASTM D2042 | %WT | Min 99 |
| Penetration, 100g, 5s, @ 25 ◦C | ASTM D5 | 0.1mm | Min 40 |
| Thin-Film Oven Test (TFOT) | |||
| Viscosity, @ 60 ◦C | ASTM D2171 | Poise (10*Pa.s) |
Max 10000 |
| Ductility, 5 cm/min, @ 25 ◦C | ASTM D113 | cm | Min 20 |
AC30 Asphalt
Bitumen AC 30 is a hard type of AC bitumen. It has a high viscosity and a low penetration value. Bitumen AC 30 is recommended for high temperature areas with heavy traffic loads.
Check the below table to know the bitumen AC 30 specification:
| Bitumen AC30 Specification | |||
|---|---|---|---|
| Specification | Test Method | Unit | Value |
| Viscosity, @ 60 ◦C | ASTM D2171 | Poise (10*Pa.s) |
3000±600 |
| Viscosity, @ 135 ◦C | ASTM D2170 | CST | Min 250 |
| Flash Point (Cleveland Open Cup) | ASTM D92 | ◦C | Min 232 |
| Solubility in Trichloroethylene | ASTM D2042 | %WT | Min 99 |
| Penetration, 100g, 5s, @ 25 ◦C | ASTM D5 | 0.1mm | Min 30 |
| Thin-Film Oven Test (TFOT) | |||
| Viscosity, @ 60 ◦C | ASTM D2171 | Poise (10*Pa.s) |
Max 15000 |
| Ductility, 5 cm/min, @ 25 ◦C | ASTM D113 | cm | Min 15 |