Bitumen, also known as asphalt, is a dark, sticky substance primarily used in road construction and roofing. It is a versatile material that has been used for thousands of years, and it continues to be an important component in the infrastructure of modern cities.
In this article, we will explore the different types and grades of bitumen available and discuss the various applications for which they are used.
Bitumen is a naturally occurring substance that is derived from crude oil. It is a complex mixture of hydrocarbons typically composed of more than 90% carbon and hydrogen. It is a semi-solid or liquid material that is black or dark brown in colour.
Types of bitumen
Bitumen is a versatile material that is used in a wide range of applications. The two main types of bitumen are natural bitumen and refined bitumen. Each type has unique properties and characteristics that make it suitable for specific applications.
Natural bitumen
Natural bitumen is derived directly from natural sources such as rock asphalt, tar sands, and oil sands. The most common form of natural bitumen is asphalt, a naturally occurring mixture of hydrocarbons found in many parts of the world.
Asphalt is a dark, viscous material that is composed primarily of hydrocarbons. It is typically composed of more than 90% carbon and hydrogen.
Tar sands and oil sands are also sources of natural bitumen, but these materials are typically more difficult to extract and process. Tar sands are a mixture of clay, sand, water, and a thick, molasses-like substance called bitumen. Oil sands are a mixture of sand, water, clay, and a heavy, viscous form of crude oil called bitumen.
Properties of natural bitumen
- Natural bitumen is a brittle material that is sensitive to temperature changes.
- It is not suitable for high-temperature applications because it can become brittle and crack.
- It is more sensitive to the elements and can deteriorate over time.
- Natural bitumen is a good waterproofing material, it has been used for thousands of years to waterproof roofs and walls.
Refined bitumen
Refined bitumen is a product that is derived from natural bitumen through a refining process. The refining process removes impurities and unwanted materials, resulting in a more consistent product in terms of composition and properties. It is a more consistent and uniform product than natural bitumen.
Types of refined bitumen
- Cutback Bitumen: It is bitumen dissolved in a solvent. It is used for cold weather paving and as a prime coat for hot mix asphalt paving.
- Emulsified Bitumen: It is bitumen emulsified with water. It is used for road construction, slurry seal, and micro-surfacing.
- Modified Bitumen: It is bitumen that has been modified with polymer additives. It is more durable and elastic than regular bitumen and is used in roofing, waterproofing, and insulation applications.
Properties of refined bitumen
- Refined bitumen is more consistent and uniform in composition and properties than natural bitumen.
- It is more resistant to temperature changes and the elements, making it more durable and longer-lasting.
- It is more elastic and flexible than natural bitumen, making it more suitable for applications requiring greater flexibility.
Both types of bitumen have their own unique properties and characteristics that make them suitable for specific applications. Natural bitumen is a brittle material sensitive to temperature changes, making it more suitable for waterproofing applications. Refined bitumen is more consistent and uniform in composition and properties, making it more suitable for road construction and other high-performance applications.
Grades of bitumen
Bitumen is available in different grades, each suited for specific applications. The grade of bitumen is determined by its penetration value and viscosity. Penetration value is a measure of the consistency of bitumen, while viscosity is a measure of its resistance to flow.
Penetration grades
Penetration grades of bitumen are classified based on their penetration value, which is measured in tenths of a millimetre (0.1 mm). The lower the penetration value, the harder and more brittle the bitumen is.
- Hard Grades: Bitumen with a penetration value of less than 50 is considered a hard grade. These grades are typically used in waterproofing and insulation applications.
- Medium Grades: Bitumen with a penetration value between 50 and 150 is considered medium grade. These grades are typically used in road construction and paving applications.
- Soft Grades: Bitumen with a penetration value greater than 150 is considered soft grade. These grades are typically used in high density road construction and paving applications.
Performance graded bitumen
Performance Graded Bitumen (PGB) is a type of bitumen graded based on its performance characteristics, such as its resistance to rutting, fatigue, and thermal cracking. PGB is designed to meet specific performance requirements and is often used in high-stress applications such as high-traffic roads, airports, and ports.
PGB is graded using two main characteristics: the Performance Grade (PG) and the high-Temperature Performance Grade (T). The PG grade measures the bitumen’s ability to resist rutting, a type of deformation that occurs in the wheel tracks of roads.
The T grade measures the bitumen’s ability to resist thermal cracking, which occurs when the bitumen is exposed to high temperatures.
One of the advantages of using PGB is that it can be tailored to meet specific performance requirements. For example, a road expected to experience high temperatures and heavy traffic can be constructed using a PGB with a high T grade. Similarly, a road expected to experience heavy rainfall can be constructed using a PGB with a high PG grade.
PGB is also widely used in the construction of new roads, in particular, those with heavy traffic or extreme weather conditions. PGB is also used to resurface existing roads to improve their performance and extend their lifespan.
Furthermore, PGB is also used in constructing airports, ports, and other high-traffic areas, as it offers improved resistance to rutting and thermal cracking. In addition, PGB is also used in the construction of parking lots and other high-traffic areas, as it offers improved resistance to rutting and thermal cracking.
Viscosity grades
Viscosity grades of bitumen are classified based on their viscosity, which is measured in poise (P). The higher the viscosity, the more resistant the bitumen is to flow.
- High Viscosity Grades: Bitumen with a viscosity of more than 180 poise is considered a high viscosity grade. These grades are typically used in roofing and waterproofing applications.
- Medium Viscosity Grades: Bitumen with a viscosity between 80 and 180 poise is considered a medium viscosity grade. These grades are typically used in road construction and paving applications.
- Low Viscosity Grades: Bitumen with a viscosity of less than 80 poise is considered to be a low viscosity grade. These grades are typically used in road construction and paving applications.
Bitumen is available in different grades based on its penetration value and viscosity. The choice of grade depends on the specific requirements of the application and the conditions in which the bitumen will be used.
Hard grades are typically used in waterproofing and insulation applications, while medium and soft grades are typically used in road construction and paving applications. High viscosity grades are typically used in roofing and waterproofing applications, while medium and low viscosity grades are typically used in road construction and paving applications.
Applications of bitumen
Bitumen is used in various applications due to its waterproofing, insulation, and adhesive properties. The most common applications of bitumen include:
Road construction and paving
One of the most common bitumen applications is road construction and paving. Bitumen is used as a binder in asphalt concrete, which is used to surface roads, highways, airports, and parking lots. The grade of bitumen used in this application is typically a medium or soft penetration grade with a medium viscosity.
Roofing and waterproofing
Bitumen is also commonly used in roofing and waterproofing applications. Bitumen-based roofing materials such as asphalt shingles and roll roofing are widely used for residential and commercial roofing.
Bitumen is also used to waterproof foundations, basements, and retaining walls. The grade of bitumen used in this application is typically a hard penetration grade with a high viscosity.
Insulation and soundproofing
Bitumen is also used in insulation and soundproofing applications. Bitumen-based insulation materials are commonly used in building and construction to insulate walls, floors, and ceilings. Bitumen is also used in soundproofing applications to reduce noise transmission through walls and floors. The grade of bitumen used in this application is typically a hard penetration grade with a high viscosity.
Adhesive and sealant
Bitumen is also used as an adhesive and sealant in various applications. Bitumen is commonly used as an adhesive in constructing wood and asphalt shingles and in producing roofing felts.
Bitumen is also used as a sealant to seal joints and seams in roofing and waterproofing applications. The grade of bitumen used in this application is typically a medium or soft penetration grade with a medium viscosity.
Other applications
Bitumen is also used in other applications, such as in the production of cable sheaths, paint, and adhesives. In industrial applications, bitumen is used as a lining material in tanks, ponds, and lagoons to prevent leakage and evaporation.
Bitumen is a versatile material widely used in various applications due to its waterproofing, insulation, and adhesive properties. The most common bitumen applications include road construction and paving, roofing and waterproofing, insulation and soundproofing, adhesive and sealant. The choice of grade depends on the specific requirements of the application and the conditions in which the bitumen will be used.
Understanding the versatility of bitumen
Bitumen is a versatile and essential material in the construction and infrastructure industry. It is widely used in various applications due to its unique properties, such as waterproofing, insulation, and adhesive. Understanding the different types and grades of bitumen is crucial in selecting the appropriate material for a specific application.
The various types of bitumen include natural bitumen, extracted from natural deposits, and processed bitumen, produced by refining crude oil. Each bitumen type has unique properties and characteristics that make it suitable for certain applications.
The grades of bitumen are determined by its penetration and viscosity properties. The penetration grade is used to measure the consistency of the bitumen, and the viscosity grade is used to measure the resistance to flow.
These properties determine the suitability of the bitumen for specific applications such as road construction and paving, roofing and waterproofing, insulation and soundproofing, and adhesive and sealant.
In conclusion, bitumen is a critical material that plays a vital role in the construction and infrastructure industry. Understanding the different types and grades of bitumen and their properties is essential in selecting the appropriate material for a specific application.
With the advancement in technology and research, new developments in the bitumen industry can be expected, opening up new possibilities and uses of this versatile material.
Don’t let your next construction project fall short of expectations. Contact Northern Highways Bitumen today and let our team of experts help you plan and execute a successful project using the latest techniques and materials. From road construction to airport runways, we have the experience and skills to get the job done right. Call us now to schedule a consultation and take the first step toward a successful project.
