Bitumen Types

The most important point in purchasing and supplying bitumen is to be familiar with its types and choose the most appropriate sample according to the intended application. In this article, Mahan Zone has examined the types of bitumen samples.
It should be noted that Mahan Zone can provide these samples; so please contact us to purchase and supply the sample you are looking for through the Contact Us section on our site.

Bitumen, also known as asphalt, is a sticky, black, and highly viscous liquid or semi-solid form of petroleum. It’s widely used in road construction, waterproofing, and roofing. There are several types of bitumen, each suited for different applications and environments. Here are the main types:

1. Penetration Grade Bitumen

• Description: Graded based on penetration tests, this bitumen’s hardness is tested by the depth a needle penetrates under specific conditions.
• Applications: Used primarily for paving and road construction.
• Examples: 40/50, 60/70, and 80/100 grades (where lower numbers indicate harder grades).

2. Viscosity Grade Bitumen

• Description: Classified based on its viscosity at a specific temperature, providing a better indication of performance in high-temperature environments.
• Applications: Roads in hot climates, offering greater temperature stability.
• Examples: VG-10, VG-20, VG-30, and VG-40 (increasing numbers correspond to higher viscosity and temperature resistance).

3. Cutback Bitumen

• Description: Made by adding solvents (like kerosene) to reduce viscosity, making it easier to work with at lower temperatures.
• Applications: Used for priming, surface dressing, and as a temporary binder, particularly in cold climates.
• Types: Rapid-Curing (RC), Medium-Curing (MC), and Slow-Curing (SC), depending on solvent evaporation speed.

4. Emulsion Bitumen

• Description: Bitumen dispersed in water, which eliminates the need for heating and allows it to be used in wet conditions.
• Applications: Used for road maintenance, patching, and surface dressing.
• Types: Cationic and Anionic emulsions, depending on the type of surfactant, which affects adhesion to aggregates.

5. Polymer-Modified Bitumen (PMB)

• Description: Modified by adding polymers to enhance properties like elasticity, durability, and temperature resistance.
• Applications: Heavy traffic roads, high-stress pavements, and areas requiring extended lifespan.
• Types: Styrene-Butadiene-Styrene (SBS), Styrene-Butadiene Rubber (SBR), and Ethylene-Vinyl-Acetate (EVA) modified bitumens.

6. Oxidized (Blown) Bitumen

• Description: Produced by blowing air through bitumen, making it more rigid and resistant to temperature variations.
• Applications: Roofing, industrial applications, and waterproofing.
• Grades: Often designated by softening point and penetration (e.g., 85/25 or 95/25).

Each type of bitumen has unique characteristics tailored to specific climate conditions, construction practices, and infrastructure needs.

1. Penetration Grade Bitumen

• Properties: Measured by a penetration test (standardized needle test at 25°C), indicating its hardness and consistency.
• Production Process: Obtained through distillation of crude oil, followed by processing to achieve the desired grade.
• Key Benefits: Reliable under moderate temperature fluctuations; can be adapted for different climates by selecting appropriate penetration grades.
• Limitations: Limited resistance to extreme temperatures, which may cause softening in high heat and brittleness in cold conditions.
• Uses: Commonly used in road construction, especially in regions with stable, moderate climates.

2. Viscosity Grade (VG) Bitumen

• Properties: Rated by kinematic viscosity, reflecting resistance to flow under specific temperatures. Grades range from VG-10 (soft) to VG-40 (hard).
• Production Process: Obtained through fractional distillation and viscosity control.
• Key Benefits: Excellent stability at high temperatures, less susceptible to temperature-induced deformation; effective in hot climates.
• Limitations: Limited suitability in colder climates due to reduced flexibility.
• Uses: Preferred for road construction in regions with high ambient temperatures or areas subject to heavy traffic loads.

3. Cutback Bitumen

• Properties: Contains volatile solvents (e.g., kerosene) to reduce viscosity, making it flow easily without heating.
• Production Process: Bitumen is combined with solvents that evaporate upon application, leaving behind a bituminous residue that hardens over time.
• Types:
  • Rapid-Curing (RC): Fast evaporation, used for tack coats or surface treatments.
  • Medium-Curing (MC): Slower evaporation, used for road mixing and prime coats.
  • Slow-Curing (SC): Very slow evaporation, suited for soil stabilization.
• Key Benefits: Simplifies application in cold climates or remote locations where heating isn’t practical.
• Limitations: Solvent evaporation can impact the environment, requiring careful handling to minimize emissions.
• Uses: Surface treatments, road patching, and prime coatings in colder climates or smaller-scale applications.

4. Emulsion Bitumen

• Properties: Bitumen is suspended in water with an emulsifying agent, forming a stable blend that doesn’t need heating for application.
• Production Process: Produced by blending bitumen with water in a high-shear mixer, along with emulsifiers.
• Types:
  • Cationic Emulsions: Positively charged, ideal for acidic aggregates.
  • Anionic Emulsions: Negatively charged, suitable for basic aggregates.
• Key Benefits: Ideal for damp or wet conditions; no need for heating, reducing energy costs and emissions.
• Limitations: Limited shelf life and storage requirements; may not bond as strongly as heated bitumen in some cases.
• Uses: Road maintenance, surface dressing, and patching. Cationic emulsions are most commonly used as they offer better adhesion to aggregates.

5. Polymer-Modified Bitumen (PMB)

• Properties: Enhanced elasticity, durability, and flexibility due to polymer modification.
• Production Process: Polymers such as SBS, SBR, or EVA are blended with bitumen, modifying its structure and performance characteristics.
• Types:
  • Styrene-Butadiene-Styrene (SBS): Provides high elasticity and resistance to deformation.
  • Styrene-Butadiene Rubber (SBR): Adds flexibility and toughness.
  • Ethylene-Vinyl Acetate (EVA): Enhances temperature resistance.
• Key Benefits: Excellent for high-stress applications and extended durability, especially under extreme temperature and heavy loads.
• Limitations: Higher cost and more complex application processes.
• Uses: High-traffic roads, airports, bridge decks, and areas exposed to heavy loads or high temperatures.

6. Oxidized (Blown) Bitumen

• Properties: More rigid and temperature-resistant due to oxidation, which alters bitumen’s molecular structure.
• Production Process: Air is blown through bitumen under controlled conditions, hardening the bitumen and making it more temperature-resistant.
• Grades: Classified based on softening point and penetration rate (e.g., 85/25, 95/25), with the first number indicating softening point and the second indicating penetration.
• Key Benefits: Improved resistance to temperature changes; doesn’t soften or flow in high temperatures and maintains flexibility in cooler temperatures.
• Limitations: Hardness can limit its use in flexible pavements; generally not suitable for typical road applications.
• Uses: Industrial applications, such as roofing, waterproofing, and manufacturing adhesives.

Additional Types of Specialized Bitumen:

• Natural Bitumen (Asphaltite): Mined from natural deposits and used in specialized applications due to high asphaltene content, offering natural viscosity and resistance.
• Multigrade Bitumen: A mix with varied penetration rates to improve both cold and heat performance, often used in climates with extreme temperature shifts.

Choosing the right bitumen depends on factors like climate, load requirements, and desired lifespan, with each type engineered to perform optimally under specific conditions.

Natural bitumen, also known as “asphaltite” or “native asphalt,” is a naturally occurring, semi-solid form of petroleum. Unlike refined bitumen, which is processed from crude oil, natural bitumen forms through the natural degradation of organic materials over millions of years. Here’s a deeper look into its properties, types, extraction methods, and applications:

Key Properties of Natural Bitumen

1. High Asphaltene Content: Natural bitumen has a high concentration of asphaltenes, giving it greater viscosity, rigidity, and durability compared to refined bitumen.
2. Low Volatile Content: Natural bitumen is less prone to evaporative loss, which enhances its longevity and stability under high-temperature conditions.
3. Thermoplasticity: It softens when heated and hardens when cooled, which is beneficial for applications like waterproofing and road surfacing.
4. High Adhesion: Natural bitumen has excellent adhesion properties, making it ideal for binding with aggregates in construction.

Types of Natural Bitumen

Natural bitumen varies in composition based on its geological formation and the extraction location. Common types include:

1. Gilsonite:
   • A type of natural asphalt found in deposits in the U.S., particularly Utah.
   • Hard, brittle, and often ground into powder for use in drilling mud, ink, paint, and industrial coatings.
2. Trinidad Lake Asphalt:
   • Extracted from the Pitch Lake in Trinidad and Tobago, this type is known for its purity and stability.
   • Used in high-performance road construction, especially in locations requiring durability and resistance to deformation.
3. Tar Sands Bitumen:
   • Found in large quantities in places like Alberta, Canada, tar sands consist of a mix of bitumen, sand, clay, and water.
   • Requires intensive processing to separate the bitumen from other materials, primarily used in the petroleum industry for synthetic crude production.
4. Rock Asphalt:
   • A natural blend of bitumen and mineral matter, often quarried and processed for road surfacing.
   • Common in locations like Kentucky and Oklahoma in the U.S. and parts of Europe.

Extraction Methods

The method used for extracting natural bitumen depends on the form it takes and its location:

1. Mining: For deposits like Gilsonite and Trinidad Lake Asphalt, open-pit mining and quarrying methods are often used to extract the bitumen.
2. Steam and Hot Water Extraction: For bitumen from tar sands, steam or hot water is injected to soften the bitumen, allowing it to be separated from other materials. This method is used predominantly for Canadian tar sands.
3. In Situ Extraction: Used when deposits are deep underground. Techniques like steam-assisted gravity drainage (SAGD) involve injecting steam to liquefy the bitumen, allowing it to flow to the surface.

Applications of Natural Bitumen

1. Road Construction: Natural bitumen, especially Trinidad Lake Asphalt, is prized for its longevity and performance in high-traffic and extreme temperature zones.
2. Waterproofing: Because of its natural thermoplasticity and high adhesive properties, it’s ideal for waterproofing applications in roofing and industrial sealing.
3. Industrial Coatings and Sealants: Gilsonite is often used in industrial applications like paints, inks, and varnishes for its hardening and binding properties.
4. Petroleum Industry: Tar sands bitumen is often upgraded into synthetic crude oil, which can then be refined like traditional crude.
5. Asphalt Additive: Natural bitumen can be mixed with refined bitumen to enhance elasticity, durability, and longevity in pavements.

Advantages of Natural Bitumen

• Durability: Natural bitumen tends to have higher resistance to wear and environmental degradation, making it ideal for long-lasting applications.
• Temperature Stability: It performs well in extreme heat and can resist softening, making it ideal for tropical climates.
• Low Environmental Impact: For applications like waterproofing, natural bitumen can sometimes reduce the need for synthetic additives.

Limitations of Natural Bitumen

• Limited Availability: Unlike refined bitumen, which can be produced in large quantities, natural deposits are limited and often costly to extract.
• Complex Extraction Process: Extracting and processing natural bitumen, especially from tar sands, can be energy-intensive and environmentally challenging.
• Consistency and Quality Variability: Natural bitumen’s properties can vary widely based on source, requiring additional processing for specific applications.

Natural bitumen continues to be valued for its unique properties and is especially useful in applications that demand high resilience and stability, particularly in road construction and waterproofing solutions.

Multigrade bitumen is a specially engineered type of bitumen designed to perform well across a wide range of temperatures. It combines the qualities of both soft and hard bitumen grades, allowing it to maintain flexibility in cold conditions and resist deformation in hot climates. This versatility makes it particularly valuable for road surfaces exposed to varying seasonal temperatures, heavy traffic loads, or extreme weather conditions.

Properties of Multigrade Bitumen

1. Enhanced Temperature Range: Multigrade bitumen maintains its stability across a broader temperature spectrum, resisting cracking in cold weather and rutting in hot weather.
2. Improved Flexibility and Elasticity: It has better elasticity than conventional bitumen, reducing the risk of cracking under stress.
3. High Resistance to Deformation: Multigrade bitumen’s modified structure prevents softening and deformation under high temperatures and traffic loads, making it suitable for regions with heavy vehicle traffic.
4. Strong Adhesion to Aggregates: The modified bitumen binds well with aggregates, providing a longer-lasting bond and improving pavement durability.

Production Process

Multigrade bitumen is produced by mixing base bitumen with special additives or modifiers, such as polymers. The modification process aims to alter the molecular structure of the bitumen, resulting in a product that behaves similarly to soft bitumen at low temperatures and hard bitumen at high temperatures. Commonly used additives include elastomers and plastomers, which enhance flexibility and temperature resistance.

Benefits of Multigrade Bitumen

1. Extended Pavement Life: Because of its ability to perform well across different temperature ranges, multigrade bitumen reduces the need for frequent maintenance and repairs, extending the lifespan of pavements.
2. Cost-Effectiveness: While the initial cost of multigrade bitumen may be higher, its durability reduces long-term maintenance costs.
3. Resistance to Environmental Factors: Multigrade bitumen provides good resistance to weather-related deterioration, reducing the effects of moisture, oxidation, and ultraviolet (UV) light.

Applications of Multigrade Bitumen

1. Road Construction in Variable Climates: Ideal for areas that experience both cold winters and hot summers, as it adapts well to seasonal temperature changes.
2. High-Traffic Roads and Highways: Used in high-stress applications like highways and busy urban roads where pavements need to withstand constant loads and resist deformation.
3. Airport Runways: Its high resistance to rutting and deformation makes it suitable for runways, which require durability and resistance to heat from friction.
4. Bridges and Overpasses: These structures experience additional flexing due to movement, making multigrade bitumen’s elasticity advantageous.

Limitations of Multigrade Bitumen

1. Higher Initial Cost: Multigrade bitumen is more expensive than traditional penetration-graded or viscosity-graded bitumen due to the additional materials and processing required.
2. Complex Application Process: The addition of modifiers requires specialized handling and equipment for mixing and application.
3. Availability: In some regions, access to multigrade bitumen may be limited due to production constraints or local demand.

Common Grades and Standards

Multigrade bitumen is typically categorized based on international standards, with grades that specify performance at low and high temperatures. Common standards include those from the American Association of State Highway and Transportation Officials (AASHTO) and the European Committee for Standardization (CEN), which ensure consistency in performance and quality across different applications.

Key Differences from Polymer-Modified Bitumen (PMB)

While multigrade bitumen and polymer-modified bitumen (PMB) may seem similar, PMB usually has more specialized additives and is generally designed for high-stress applications with extreme temperature ranges. Multigrade bitumen, on the other hand, provides a balance between flexibility and hardness without requiring the extensive polymerization typical of PMB, making it more accessible for widespread infrastructure applications.

Multigrade bitumen is thus an adaptable and cost-effective option for many road construction projects, offering a balance of flexibility and strength that is ideal for regions with varied climates or heavy traffic demands. Its development reflects ongoing innovations aimed at producing longer-lasting, resilient infrastructure materials.