Containing elements such as sulfur, iron, oxygen, and calcium, bitumen is kind of a side product of crude oil. In addition, complex hydrocarbons compose this material. Just like every product, there are factors affecting its quality and ease of production, such as the type of crude oil or its source. When we check the early usage of bitumen, we see that it was used for its waterproofing and adhesive features. But, as the years passed and new studies were developed, we could now use it for road construction as well. For example, according to recent announcements, the great majority of U.S. roads are made of bitumen. Let’s see what bitumen is
Bitumen Extraction
We would like to state that bitumen extraction plants differ in facilities, operations, and other aspects. But, to make it clear, we will share two main recovery circuits:
Primary recovery circuit: As is mostly agreed, we can say that the primary recovery circuit, consisting of a gravity separation cell, is the heart of bitumen extraction plants. The sizes of the gravity separation cells can vary, but commonly, the smallest cells are between 24 and 30 meters wide.
Secondary recovery circuit: The extraction aims to remove tar sands, or crude oil, from bitumen. During this process, middlings, the fractions falling between the heaviest and the lightest components, occur. So, during the secondary recovery circuit, consisting of flotation cells, the middle stream is removed from the bitumen.
To make it more detailed, we would like to share three streams that the main vessel produces: overflow, middlings, and underflow. Lastly, it is better to indicate that some plants also have a tertiary bitumen recovery circuit where the material is recovered from the underflow.
Bitumen Production
Just like the extraction process, the production process also varies according to facility and operator conditions. Here are the basic production methods for bitumen.
Distillation: As mentioned above, facilities produce bitumen from crude oil. After the extraction, the crude oil arrives at the refinery, where it goes through distillation. This process aims to separate several components of the crude oil.
Vacuum Distillation: In this process, the residual fractions are processed in a more detailed way to obtain high-quality bitumen.
De-Asphalting: This process involves mixing solvent with crude oil in order to extract lighter hydrocarbons from heavier asphaltic components. After removing the solvent, you can get high-quality bitumen.
Oxidation: This method is also known as blown bitumen. In this process, the air passing through heated bitumen helps produce the final product. This method greatly increases the viscosity and softening point of bitumen.
Cutback: It is a mixture of a solvent that lowers the viscosity and bitumen. After application, the solvent evaporates, and high-quality bitumen can be produced.
Use of Bitumen in Road Construction
Asphaltic bitumen plays a vital role with its unique features and advantages. We can summarize the importance of bitumen in road construction as follows:
Binder: Bitumen has a binder characteristic that holds aggregate particles together and forms a cohesive and durable pavement system.
Flexibility: The flexibility of the material allows it to accommodate slight movements. In addition, it prevents deformations caused by traffic loads, settling of the underlying soil, or temperature fluctuations. In conclusion, the elasticity of bitumen makes the road more durable.
Waterproofing: Bitumen is known for its characteristic waterproofing. This characteristic makes it an effective barrier against moisture. Therefore, the material is resistant to freeze-thaw cycles. As we can conclude, asphaltic bitumen has an extended lifespan in regions with different climate conditions.
Durability: As we listed above, bitumen has binding, flexible, and waterproof characteristics. These features make the material durable and wear-resistant. In addition, the material has the ability to keep itself safe from the stresses of traffic loads.
Rut Resistance: Due to traffic loading, repetitive deformations can be observed on the pavements. Thanks to the viscosity and elasticity of bitumen, such repetitive deformation is prevented. In addition, this material ensures a smoother and safer driving surface for all types of vehicles.
Easy Application: To make it more convenient for road construction, bitumen is applied at low temperatures. This reduces emissions and energy consumption during the construction process. Due to its ideal viscosity rate and elasticity, it is also easy to apply the material to the pavement.
Sustainability: The best part of bitumen is that it is a sustainable solution. Because this material can be reclaimed and reused from old pavements. The process is not limited to cold recycling. Bitumen can also be returned with a hot-in-place recycling method.
Noise Reduction: Every item seems to have the best characteristic. Asphaltic bitumen provides noise reduction benefits on roads. So, to achieve quieter and more comfortable roads, it is better to choose bitumen for road construction material.
Versatility: What makes a material perfect? We think it’s versatile. Because the more versatile a material, the more it becomes useful and functional. Bitumen can be blended with other materials to enhance its performance characteristics.
Economic: Let us summarize the importance of bitumen in road construction in this item. Bitumen is a binding, flexible, durable, water-resistant, rut-resistant, easy-to-apply, sustainable, and versatile material. All these characteristics make it an economic solution for road construction.
Summary
Bitumen is a side product of crude oil. At first, the material was used for waterproofing and adhesion purposes; later, companies started using it for road construction. Bitumen is an important element in this business. because it is a binding, sustainable, economical, versatile, and durable solution for pavements.
FAQ
Which bitumen is used for road construction?
Asphaltic bitumen, made from a byproduct of crude oil, is used for road construction. The reason it is used is because it is easy to produce and apply. Besides, this material is non-toxic and has a strong binder.
Which bitumen grades is best?
Bitumen has several grades. According to studies, VG10 bitumen is the softest of all. Therefore, for paving roads, VG10 would be a good option to use.