All About Bitumen Prime Coat Calculation

All About Bitumen Prime Coat Calculation

Bitumen prime coat is a crucial element in the construction of roads, providing a sturdy foundation for the layers above. This thin layer of bitumen emulsion not only increases the adhesion between the base layer and the subsequent asphalt layers, but also protects the base from water infiltration, reducing the chances of potholes and cracks. However, the calculation of bitumen prime coat quantity can be a challenging task, requiring a thorough understanding of various factors such as the type and condition of the surface, weather conditions, and traffic volume. In this article, we will delve into the intricacies of bitumen prime coat calculation, and explore the various methods and factors to consider for an accurate and efficient application.

Bitumen Prime Coat Calculation

Bitumen Prime Coat Calculation

Bitumen prime coat is a fundamental component in the construction of asphalt pavements. It is applied to the surface of the base course before the placement of the asphalt layer. The purpose of a prime coat is to protect the base course from moisture intrusion and improve adhesion between the base course and the asphalt layer. For this reason, it is essential to calculate the required quantity of bitumen prime coat accurately. The following are the steps involved in bitumen prime coat calculation:

1. Determine the area to be primed: The first step in calculating the bitumen prime coat is to determine the area of the base course that needs to be primed. This can be done by measuring the length and width of the base course in meters and then multiplying them to get the area in square meters.

2. Calculate the required thickness: The prime coat thickness is typically between 0.10 to 0.15 mm. The recommended thickness may vary depending on the type of base course and its condition. Hence, the required thickness should be determined based on the project specifications.

3. Calculate the volume of prime coat: Once the area and thickness of the prime coat are known, the required volume of prime coat can be calculated using the formula:

Volume (m3) = Area (m2) X Thickness (m)

4. Convert the volume to liters: Bitumen prime coat is usually applied in liters per square meter (L/m2). Therefore, the volume of prime coat calculated in step 3 should be converted to liters. This can be done by multiplying the volume by 1000.

5. Determine bitumen content: Bitumen prime coat typically consists of 80% bitumen and 20% water. Hence, to determine the bitumen content, the volume of the prime coat calculated in step 4 should be multiplied by 0.8 (80%).

6. Adjust for wastage: A certain percentage of the prime coat is typically lost due to wastage during application. Depending on the contractor’s experience, 10-15% of the calculated bitumen content should be added to account for wastage. For example, if the calculated bitumen content is 200 liters, the final quantity required would be 230 liters (200 liters + 30 liters for wastage).

7. Purchase the required quantity: The final quantity calculated in step 6 should be purchased to complete the prime coating of the designated area.

In conclusion, calculating the required quantity of bitumen prime coat is crucial for a successful pavement construction project. It is essential to accurately determine the area, thickness, and bitumen content to achieve the desired results. Additionally, the wastage factor should also be considered to avoid any delays or extra costs during the construction process.


In conclusion, understanding the basics of bitumen prime coat calculation is crucial for any construction project involving asphalt pavements. By properly calculating the amount of bitumen prime coat needed, contractors can ensure the stability and longevity of their roadways, while also minimizing excess costs. It is important to consider factors such as surface type, climate conditions, and application method when determining the appropriate amount of prime coat to use. With the knowledge and use of proper calculation techniques, construction teams can effectively plan and execute their projects, resulting in durable and high-quality roadways. Overall, the proper calculation of bitumen prime coat is an essential component in the successful construction and maintenance of asphalt pavements.


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