Coal Product Used in Surfacing the Road: Coal Tar

Coal tar is the coal product used in surfacing the road. It is a black, sticky, and highly viscous liquid obtained during the process of coal carbonization. Coal tar has been used for centuries in various applications, including road surfacing due to its excellent binding properties and durability.

What is Coal Tar?
- Coal tar is a thick, black liquid that is a byproduct of the destructive distillation of coal. It is obtained by heating coal in the absence of air at high temperatures, resulting in the decomposition of coal into various byproducts.
- The process of coal carbonization involves heating coal to produce coke, coal gas, and coal tar. Coal tar is collected and separated from the other byproducts through a series of cooling and condensation processes.

Properties and Characteristics of Coal Tar:
- Sticky and Viscous: Coal tar is a highly sticky and viscous liquid, which makes it an excellent binder for road surfaces.
- Water Repellent: It has water-repellent properties, preventing water from penetrating into the road surface and reducing the risk of damage caused by water seepage.
- High Durability: Coal tar is highly durable and can withstand heavy traffic loads, making it suitable for surfacing roads.
- Thermal Stability: It has good thermal stability, resisting damage caused by temperature fluctuations and preventing cracks in the road surface.
- Chemical Resistance: Coal tar is resistant to various chemicals, including gasoline and oils, which helps protect the road surface from damage due to spills and leaks.

Advantages of Using Coal Tar in Road Surfacing:
- Excellent Binding Properties: Coal tar has strong adhesive properties, ensuring that the aggregates in the road surface are firmly bound together.
- Longevity: Roads surfaced with coal tar have a longer lifespan compared to other materials, reducing the need for frequent repairs and maintenance.
- Waterproofing: Coal tar acts as a waterproofing agent, preventing water from seeping into the road surface and causing damage.
- Chemical Resistance: It provides protection against chemical spills and leaks, reducing the risk of road deterioration.
- Cost-Effective: Although the initial cost of using coal tar may be higher, its long-term durability and reduced maintenance requirements make it a cost-effective choice in the long run.

In conclusion, coal tar is the coal product commonly used in surfacing the road due to its excellent binding properties, durability, and resistance to water and chemicals. It provides a long-lasting, cost-effective solution for road construction and maintenance.

B) coal tar

because bitumen is the petroleum product used in surfacing road