Bitumen
- Penetration Grade Bitumen
The penetration grade bitumen with solid and semi-solid states are obtained directly from the distillation of crude oil or other additional operations such as air blowing. These products come out of the bottom of the distillation tower and are often called pure bitumen or penetration grade bitumen, obtained by selecting the appropriate distillation method. This bitumen is obtained through the aeration process on the vacuum bottom (raw material for bitumen production is taken from the bottom of the distillation tower in vacuum) in bitumen production units. The air- blowing process, oxidation, includes a series of complex chemical interactions such as dehydrogenation and polymerization, which can increase the carbon-to-hydrogen ratio, making the bitumen gradually harder. It allows for the production of different grades of bitumen. These types of bitumen have a wide range of applications and higher consumption rates than other types.
This bitumen divided by the degree of penetration include 10/20 to 220/160, in 6 grades used in different cases according to their characteristics. The thermoplastic properties of these bitumen grades make them softer at high temperatures and harder at lower degrees.
- APPLICATIONS OF PENETRATION GRADE BITUMEN
The penetration grade bitumen is mainly used for road construction, preparation of hot asphalt mix, and some other purposes. Over the last three decades there has been a greater tendency to use harder bitumen and produce asphalt with higher properties than soft bitumen in most road construction projects. In general, harder bitumen grades (with lower degrees of penetration) are recommended for areas with warmer climates, whereas softer bitumen (higher degree of penetration) are suggested for areas with colder climates. These bitumen should be used at a temperature between 220–250 ºC and should not be heated above 270 ºC.
- PROPERTIES OF PENETRATION GRADE BITUMEN
The characteristic features of penetrating bitumen are their degree of penetration and softening point. The higher the degree of penetration, the lower the softening point and the softer the bitumen becomes.
Property | Unit | Test Method | 10/20 | 40/50 | 60/70 | 85/100 | 90/130 | 160/220 | ||||||||||
1 | Specific Gravity @ 25/25 ºC | * | ASTM D70 | 1.01-1.06 | 1.01-1.06 | 1.01-1.06 | 1.01-1.05 | 1.01-1.04 | 1.01-1.05 | |||||||||
2 | Penetration @ 25 ºC | 0.1mm | ASTM D5 | 44854 | 40-50 | 60-70 | 85-100 | 90-130 | 160-220 | |||||||||
3 | Softening Point | ºC | ASTM D36 | 58-66 | 52-60 | 49-56 | 45-52 | 43-47 | 35-43 | |||||||||
4 | Ductility @ 25 ºC | cm | ASTM D113 | >5 | >100 | >100 | >100 | >100 | >100 | |||||||||
5 | Loss On Heating | wt% | ASTM D6 | 0.2 max | 0.2 max | 0.2 max | 0.2 max | 0.2 max | 0.2 max | |||||||||
6 | Drop in Pen. After Heating | % | ASTM D5 & D6 | 20 max | 20 max | 20 max | 20 max | 20 max | 20 max | |||||||||
7 | Flash Point | ºC | ASTM D92 | 225 min | 250 min | 250 min | 225 min | 250 min | 250 min | |||||||||
8 | Solubility In TCE | wt% | ASTM D4 | 99.5 min | 99.5 min | 99.5 min | 99.5 min | 99.5 min | 99.5 min | |||||||||
9 | Spot Test | * | A.A.S.H.O.T 102 | Negative | Negative | Negative | Negative | Negative | Negative | |||||||||
- Viscosity Grade Bitumen
Viscosity Grade (VG) bitumen is a standard grade of bitumen applicable for road construction and asphalt production with superior properties Since this group of bitumen has the viscoelastic behavior, more strong and flexible connections between the bitumen and the building materials takes place, depending on the mixing speed of the materials. Viscosity, more than two other common characteristics, namely softening point and penetration, can represent the properties of bitumen. Therefore, viscosity-based classification (degree of fluidity) is separately presented, and codes AC-2.5 to AC-40 are employed to classify the properties of bitumen. Different types of bitumen are classified regarding their absolute viscosity at 60 °C in poise and/or kinematic viscosity at 135 °C in centistokes.
These types of bitumen show thermoplastic properties that soften the bitumen at higher temperatures and become harder at lower temperatures. This temperature-viscosity relationship is uniquely important in determining functional parameters such as adhesion, rheology, durability, and the temperature application of bitumen. Regarding the viscosity grade bitumen, there is more emphasis on the ductility of the product.
Property | Unit | Test Method | 10/20 | 40/50 | 60/70 | 85/100 | 90/130 | 160/220 | ||||||||||
1 | Specific Gravity @ 25/25 ºC | * | ASTM D70 | 1.01-1.06 | 1.01-1.06 | 1.01-1.06 | 1.01-1.05 | 1.01-1.04 | 1.01-1.05 | |||||||||
2 | Penetration @ 25 ºC | 0.1mm | ASTM D5 | 44854 | 40-50 | 60-70 | 85-100 | 90-130 | 160-220 | |||||||||
3 | Softening Point | ºC | ASTM D36 | 58-66 | 52-60 | 49-56 | 45-52 | 43-47 | 35-43 | |||||||||
4 | Ductility @ 25 ºC | cm | ASTM D113 | >5 | >100 | >100 | >100 | >100 | >100 | |||||||||
5 | Loss On Heating | wt% | ASTM D6 | 0.2 max | 0.2 max | 0.2 max | 0.2 max | 0.2 max | 0.2 max | |||||||||
6 | Drop in Pen. After Heating | % | ASTM D5 & D6 | 20 max | 20 max | 20 max | 20 max | 20 max | 20 max | |||||||||
7 | Flash Point | ºC | ASTM D92 | 225 min | 250 min | 250 min | 225 min | 250 min | 250 min | |||||||||
8 | Solubility In TCE | wt% | ASTM D4 | 99.5 min | 99.5 min | 99.5 min | 99.5 min | 99.5 min | 99.5 min | |||||||||
9 | Spot Test | * | A.A.S.H.O.T 102 | Negative | Negative | Negative | Negative | Negative | Negative | |||||||||