Types of Bitumen We Provide
There are several types of bitumen available, each with its own set of features, standards, and applications dependent on the needs of the consuming sector. Bitumen specifications vary in terms of safety, solubility, physical qualities, and durability. The design of physical characteristics of the material is critical for understanding the performance of bitumen in service. Bitumen is graded using industry-standard testing procedures.
Bitumen has a variety of applications, but its usage in road construction and maintenance, either directly or through asphalt, accounts for about 90% of total demand. Approximately 90% of the bitumen produced is used in road construction operations, with the remaining 10% used for insulating purposes.
Paving grades, cutback bitumen, and bitumen emulsions are all important bitumen kinds for road uses. Paints, sealants, adhesives, enamels, waterproofing, electrical products, flooring materials, back carpet tiles, land and marine pipe coatings, and a variety of other non-road applications employ hard, oxidized, and blown grades, as well as mastic asphalt.
The bitumen kinds in terms of their generating source Bitumen is classified into three types:
Coal Tar Pitches
Natural bitumen or native asphalts (Gilsonite) are a type of bitumen that has been created naturally through time as a result of climate conditions and is utilized without the need to be processed in distillation ways; they vary greatly in composition and qualities. This type of bitumen is known as natural bitumen. Uintaite is another name for natural bitumen.
Some varieties of bitumen occur naturally as a result of the gradual transfer of crude oil near the earth’s surface and the evaporation of its volatiles over many years.
Such bitumen can be found in nature in pure form (lake bitumen), such as Behbahan Lake Bitumen in Iran and Trinidad Lake Bitumen in the United States, or it can be extracted from mines (mineral bitumen). Natural bitumen examples include rock bitumen and lake bitumen.
Coal Tar Pitches
Coal tar Pitches are hard black substances generated during the distillation of coal tar. Their new broken surface is glossy, and when heated, they melt along with a rapid decrease in viscosity, and their melting point depends on the manufacturing procedure.
Petroleum asphalts are made from bitumen extracted from petroleum. These are solid and semi-solid bitumen that are produced directly from petroleum by distillation or indirectly through additional operations such as air blowing. This type of bitumen is known as petroleum bitumen or distilled bitumen.
Petroleum bitumen is the final result of two stages of distillation in a distillation tower. Light components such as gasoline and propane are extracted from crude oil during the first step of distillation. This process occurs at a pressure of around one atmosphere (units). Heavy chemicals such as diesel and kerosene are separated in the second step. This procedure occurs at near-vacuum pressure. Finally, a combination of solid pieces known as asphaltene is left, which is floating in a grease-like fluid known as Malton. The outcome of two phases of crude oil distillation in the distillation tower is petroleum bitumen.
Petroleum bitumen from crude oil refining entered the market in the early twentieth century, and it quickly supplanted mineral and natural bitumen in asphalt pavements and other industrial applications.
Until the late nineteenth century, the bitumen used in road and street building was a mix of mineral bitumen, bitumen stone, bitumen mastic, and stone powder, all of which were classified as mineral or natural bitumen. They are more widely used and have a wider range of applications than the other types.
Bitumen types may be categorized into two groups based on their application:
Road construction or thin bitumen;
Building bitumen and (roof insulator) or hard bitumen
Road construction or thin bitumen
Bitumen is an adhesive that is used to bind the inorganic components of asphalt in asphalt toppings and bituminous layers of highway constructions (sand, broken stone, ballast, most frequently limestone dust).
The vast majority of bitumen is used in road construction and by municipalities to coat streets. Bitumen for road construction is often classified based on its penetration. The penetration rate of bitumen material shows its strength and hardness, which is defined as the number of penetration units (one tenth millimeter) of one vertical standard needle in one bitumen sample, during a certain time and weight on the needle, and at a specific temperature. Bitumen penetration rate is typically tested at 25 degrees Celsius with a 100-gram weight and in 5 seconds. Bitumen for road construction is “60 to 70” and “85 to 100.”The numbers represent the range of bitumen penetration rate. Bitumen is hydrocarbon substance which is black to dark brown and quite solvable in carbon-sulfur. It is solid in normal environment temperature but in increased temperature, it first becomes a paste and then liquid. It has two important properties, impenetrable against water and adhesiveness which makes it an important material for the application.
Road bitumen range:
Modified bitumen products are more durable and are generally utilized on high-traffic highways. When compared to road bitumen, these varieties are more flexible and can withstand temperature variations on a larger scale.
Polymer Modified Bitumen – Polymer is utilized to alter the Bitumen in this form of Bitumen.
Modified bitumen range:
Modified bitumen 10/40-65
Modified bitumen 25/55-65
Modified bitumen 45/80-65
Modified bitumen 45/80-75
Modified bitumen 25/55-65
Rubber bitumen is produced by recycling the rubber components of waste tires. Meanwhile, roads with this type of rubber bitumen pavement can have a longer lifespan and lower maintenance costs than roads with traditional asphalt, which has a higher load factor. Traffic noise may be minimized and vehicle stopping distances can be lowered thanks to the new rubber bitumen-type asphalts.
Natural Rubber Modified Bitumen and Crumb Rubber — Crumb rubber and natural rubber are also used as bitumen modifiers.
2. Building bitumen or industrial bitumen
Building bitumen completely satisfies the limit values given in conventional bitumen test techniques. Furthermore, they strengthen the durability of the roofing and water proofing felts created from them and ensure suitable age resistance.
Types of Bitumen and their Properties and Uses
The grade types of bitumen can be classified into five types, their properties and uses are elaborated in the following sections:
Penetration Grade Bitumen
Oxidized Bitumen Grades
Cut Back Bitumen
Viscosity Graded Bitumen
Performance Graded Bitumen
Polymer Modified Bitumen
Penetration Graded Bitumen / Penetration Grade Bitumen
Penetration bitumen is produced in a variety of viscosities by fractional / vacuum distilling crude oil and is categorized based on its penetration range.
The penetration test is used to describe the bitumen on the basis of hardness. As a result, it is known as penetration bitumen. The depth to which a standard needle will penetrate under specific test conditions is used to classify graded bitumen. This “pen” test classification is used to determine bitumen hardness, with lesser penetration indicating harder bitumen. Penetration graded bitumen specifications often indicate the penetration range for a grade, such as 50/70. Other tests, such as softening point, solubility, flash point, and so on, are used to categorize bitumen for specification purposes.
Penetration grades are ideal bitumen for asphalt and Road Construction due to their durability and temperature resistance. This type of bitumen is most commonly used for manufacturing of bitumen emulsions, polymer modified binders and cutback bitumen and also for the manufacture of hot mixed asphalt as a tack coat in surface treatment.
The bitumen penetration can be classified into the following grade types:
Bitumen Penetration 30/40
Bitumen Penetration 40/50
Bitumen Penetration 50/70
Bitumen Penetration 60/70
Bitumen Penetration 80/100
Bitumen Penetration 85/100
The softest degree is called Bitumen Penetration 100/120.
The hardest degree is called Bitumen Penetration 20/30.
Oxidized Grade Bitumen
Oxidized Bitumen are produced by the addition of processed air. Passing hot air over bitumen can be used to change its physical features for particular commercial applications. This process gives the bitumen more rubbery characteristics than its original composition, resulting in harder bitumen.
The air is introduced under pressure into soft bitumen while maintaining a constant temperature. The reaction of the introduced oxygen and bitumen components produces compounds with a larger molecular weight. As a result, the Asphaltenes and Maltenes content rises, resulting in a harder mix. The ductility and temperature susceptibility of this harder mix are reduced.
The oxidized bitumen products’ nomenclature and classification are based on a combination of the temperature at which the bitumen reaches a specific “softness” when heated up, as represented by the ring and ball softening point test, and the penetration value.
The oxidized bitumen is used in a variety of industrial applications, including sealing saw cuts and joints with minimal predicted movement, roofing, waterproofing, and pipe coating, and is also used for the manufacture of sound dampening felts, under carriage sealant, roofing felt, electric cable joints, joint filling compound, sealant compound, bituminous marine mastic for oil and gas pipeline joints, and many other applications under controlled temperature conditions. For instance, as an anti-slip layer compound in the piling industry and as sound dampening in the automotive industry.
This technique of processing can provide bitumen with a reduced penetration, which can be used for road paving.
Oxidized bitumen most used grades:
Low Oxidized Bitumen: R75/25, R75/30, R85/25, R85/40, R95/25, R90/40
Medium Oxidized Bitumen: R90/10, R90/15
Hard Oxidized Bitumen: R115/15, R110/15, R105/5, R105/15, R105/35, R150/5
Cutback Bitumen or as it is called Liquid Bitumen, is a kind of bitumen or Asphaltum that has been dissolved in a solvent. Naphtha, gasoline and kerosene, white spirit, and other common solvents include these.
Bitumen is ‘cutback’ by adding small amounts of petroleum distillates such as kerosene. This is done to temporarily lower the viscosity of the asphaltum so that it can penetrate pavements more efficiently or to allow spraying at temperatures too cold for successful sprayed sealing with neat Asphaltum. After application, the components used to cut back bitumen will evaporate, leaving the remaining substance with a hardness similar to the original asphaltum.
In road construction, the material must be fluid in nature at the moment of laying, i.e. during surface dressing. It is also critical for the material to return to its previous hardness and properties after setting. The fluidity is obtained for any bitumen by raising the temperature. Any bitumen may be made more fluid by raising the temperature. This is ensured by cutback bitumen. On the other hand, Cutback bitumen, is used when fluidity at lower temperatures is required during surface dressing.
The curing time is controlled by the kind and dilution of solvent, while the amount and volatility of the oil added influence the viscosity of the Cutback Bitumen.
Cutback Bitumen grades
Slow Curing (SC Grade)
Medium Curing (MC Grade)
- Medium Curing Cutback Bitumen (MC3000)
- Medium Curing Cutback Bitumen (MC250)
- Medium Curing Cutback Bitumen (MC800)
- Medium Curing Cutback Bitumen (MC70)
- Medium Curing Cutback Bitumen (MC30)
Rapid Curing (RC Grade)
- Rapid Curing Cutback Bitumen (RC3000)
- Rapid Curing Cutback Bitumen (RC800)
- Rapid Curing Cutback Bitumen (RC250)
- Rapid Curing Cutback Bitumen (RC70)
- Rapid Curing Cutback Bitumen (RC30)
Bitumen Emulsion is a two-phase system composed of two immiscible liquids, water and asphaltum.
An emulsifier with a long hydrocarbon chain and either a cationic or anionic ending is employed as a surface active agent should be mixed with water before adding asphaltum because asphaltum is an oil and cannot be combined with water. The addition of an emulsifier to water facilitates in the breakdown of asphalt into minute particles and maintains it disseminated in suspension. An electrochemical environment is provided by this emulsifier. The ionic part of the chain is drawn to water, whereas the hydrocarbon part is attracted to bitumen. As a result, bitumen emulsion is a liquid product composed of three components (water + emulsion + asphaltum) in which droplets of asphaltum are suspended in water.
Viscosity Grade (V) Bitumen
Viscosity Grade Bitumen, often known as Asphalt, is a standard petroleum grade Asphaltum that is manufactured from fractional vacuum bottom from crude oil distillation that is frequently used as paving for road construction and asphalt pavements manufacturing with superior properties.
VG Bitumen is primarily employed in the production of hot mix asphalt for bases and wearing courses, and it has traits and properties that distinguish it from other agents. They produce exceptionally flexible and persistent connections with other materials, owing mostly to Asphaltum’s viscoelastic reaction, its usage and the behavior of which are temperature dependent.
Bitumen is classified according to its absolute viscosity at 60 degrees Celsius or its kinematic viscosity at 135 degrees Celsius. The nominal viscosity preceded by a V, is often given in specifications for viscosity graded bitumen.
Viscosity Grade (VG) Bitumen Grades
Performance Grade (PG) Bitumen
Asphaltum that has been graded based on its performance at various temperatures is known as Performance Grade (PG) bitumen.
Long-Term Pavement Performance (LTPP) has provided a method for calculating the temperature of the pavement depending on the temperature of the air above. This relatively new approach of classifying bitumen is based on temperature variations. It is a completely scientific method for studying the mechanical properties of bitumen. A temperature range for bitumen is specified in this method, and the consumer may readily select the required product. The greatest and lowest temperatures of the pavement are estimated as a result, and the bitumen that works effectively in that temperature range is selected. A wider PG range means higher resistance and more favorable specifications.
PG Grades with the best resistance in thermal cracking:
- PG 64 -22
- PG 76 -22
- PG 64 -28
- PG 58 -34
PG Grades with the best resistance against rutting:
- PG 82 -22
- PG 76 -28
- PG 70 -28
- PG 76 -22
Common in toll roads (high Volume)
- PG 64-22
Common in toll booth (high volume and slow traffic)
- PG 70-22
Common in the rest area (high volume and standing traffic)
- PG 76-22
Polymer Modified Bitumen (PMD)
Polymer modified bitumen is a mixture made of bitumen polymers that modify the viscos-elastic behavior of the bitumen, making it more appropriate for varied stresses , it is produced by modifying the strength and rheological qualities of penetration graded bitumen. This is accomplished by adding 2 to 8% polymer. Including SBS (styrene butadiene styrene), SBR (styrene butadiene rubber) and EVA (ethylene vinyl acetate)
Styrene–butadiene–styrene (SBS) is the most often used polymer for bitumen modification, followed by other polymers such as styrene–butadiene–rubber (SBR), ethylene-vinyl-acetate (EVA), and polyethylene. SBS block copolymers are elastomers that improve the elasticity of bitumen.
These polymers change the bitumen’s strength and viscoelastic qualities.
This is achieved by:
- Increasing the elastic response
- Enhancement of the cohesive characteristic
- Increased Fracture Strength
- Adding ductility
Because of its waterproof property to resist adverse weather conditions, polymer modified bitumen is one of the most useful bitumen grades that is used in manufacturing pavement, roadways for high traffic, and residential roofing solutions.
Although polymer modified bitumen is more expensive than pure bitumen, it is considered more cost effective due to the economic benefits of reducing road maintenance expenses.