Bitumen Classification
Paving Grade Bitumen by Australian Standards are categorized according to viscosity (degree of fluidity) gradings. The higher the grade, the stiffer the bitumen. Most high performing roads in Australia are built and maintained using bitumen because it is durable and has exceptional waterproofing and adhesive properties. Bitumen’s used in road construction and maintenance are refined and blended to meet strict road engineering requirements and industry specifications.
Paving Grade Bitumen Class 170
Class 170 bitumen is widely used in sprayed sealing and light asphalt applications to provide durability and fatigue resistance. It is also used to manufacture cutback bitumen’s, bitumen emulsions and modified bitumen’s.
Class 170 bitumen is commonly used in road construction and asphalt paving applications, particularly in regions with temperate climates. It provides good durability and resistance to temperature fluctuations, making it suitable for various road surfaces and conditions.
Paving Grade Bitumen Class 240
Class 240 bitumen is for use in sprayed sealing applications where the local road agency has a preference for a slightly more viscous bitumen than Class 170.
Class 240 bitumen is commonly used in road construction and asphalt paving applications, particularly in regions with temperate to hot climates. It offers good stability and resistance to deformation under high temperatures, making it suitable for durable road surfaces.
Paving Grade Bitumen Class 320
Class 320 bitumen is most commonly used to manufacture asphalt mixes. Due to its higher viscosity, stiffer asphalt mixes can be produced to improve resistance to shoving and other problems associated with higher temperature and traffic loads.
Class 320 bitumen is commonly used in road construction and asphalt paving applications, especially in regions with hot climates or heavy traffic loads. It provides excellent stability and resistance to deformation under high temperatures, making it suitable for durable and long-lasting road surfaces.
Paving Grade Bitumen Class 450
Class 450 bitumen is for use in the manufacture of asphalt mixes where the local road agency has a preference for a slightly more viscous bitumen than Class 320.
Class 450 bitumen is typically used in road construction and asphalt paving applications, especially in regions with high temperatures and heavy traffic loads. It offers superior stability and resistance to deformation under extreme conditions, making it suitable for demanding road surface requirements.
Bitumen Class 600
Class 600 bitumen is primarily used to manufacture extra heavy-duty asphalt pavements that need to endure substantial traffic loadings.
This classification indicates a relatively harder consistency compared to lower penetration grades. Class 600 bitumen is often used in road construction and asphalt paving applications, particularly in regions with hot climates or where there are high traffic loads. It offers excellent resistance to deformation under high temperatures and heavy traffic, contributing to the durability and longevity of road surfaces.
Applications
The table below shows typical applications for paving grade bitumen’s:
Storage & Handling
The storage of bitumen’s for prolonged periods at elevated temperatures should be avoided as quality may be adversely affected. As a general rule, bitumen should be stored at the lowest temperature that enables practical use. For normal operations, such as blending and transferring liquid bitumen, temperatures of 10°C to 40°C above the minimum pumping temperature are recommended.
Application Temperature Recommendations
| Type | C170 | C240 | C320 | C450 | C600 |
| Asphalt Mixing | 150 – 160°C | 155 – 165°C | 155 – 165°C | 160 – 170°C | 165 – 175°C |
| Asphalt Compaction | 135 – 150°C | 140 – 155°C | 140 – 155°C | 145 – 160°C | 150 – 165°C |
| Sprayed Sealing | 175 – 185°C | 180 – 190°C | 180 – 190°C | N/A | N/A |
Typical Characteristics
| Type | C170 | C240 | C320 | C450 | C600 |
| Viscosity at 60°C, Pa.s | 170 | 240 | 320 | 450 | 600 |
| Viscosity at 135°C, Pa.s | 0.4 | 0.45 | 0.53 | 0.66 | 0.8 |
| Viscosity at 60°C, after RTFO, Pa.s | 300 | 470 | 640 | 920 | 1300 |
| Penetration at 25°C, dmm | 70 | 58 | 46 | 36 | 27 |
| Flashpoint, 60°C | 360 | 360 | 360 | 360 | 360 |
| Viscosity of residue at 60°C, % of original | 180 | 190 | 200 | 205 | 215 |
| Density at 15°C, kg/m3 | 1.04 | 1.04 | 1.04 | 1.04 | 1.04 |
Health & Safety
To ensure hot bitumen is used in a safe and efficient manner the following safety precautions must be followed:
– Wear suitable personal protective equipment (PPE) at all times. Full skin protection is required to avoid accidental burns when transferring or handling hot bitumen.
– Always prevent contact between water and hot bitumen by checking the contents of the previous load before loading bituminous products into tankers and by following procedures to avoid violent boil-over of tanks.
– Avoid exposure to fumes by standing back on the gantry or upwind until the vapors have dispersed.
– Minimize bitumen fume by heating bitumen and asphalt products to the recommended temperatures.
– Minimize the use of diesel when cleaning equipment as this contributes to the bitumen fume.
