12.5mm vs 9.5mm Asphalt Paving: Which Is Right for Your Project?

When it comes to choosing the right asphalt paving for your project, the thickness of the asphalt plays a crucial role in ensuring the longevity and durability of the pavement. Two commonly used asphalt thicknesses are 12.5 mm and 9.5 mm. The 12.5 mm Superpave, with a minimum lift thickness of 2 inches, is preferred for heavy-duty applications where the pavement needs to withstand substantial traffic and load. It’s essential to check the aggregate sizes of the mix design before using it in thinner lifts to ensure optimal performance and strength. Ultimately, selecting the right asphalt thickness depends on the specific requirements and traffic conditions of your project.

How Thick Should New Asphalt Be?

When it comes to determining the appropriate thickness for new asphalt, various factors need to be taken into consideration. While a 4-inch thickness can provide adequate performance, opting for a greater thickness can offer additional benefits. For a stronger and more stable driveway that can withstand a wider range of climate conditions and heavy loads, a thickness of 5 or even 6 inches of full-depth asphalt is recommended.

Additionally, some contractors may choose to incorporate a base layer of compacted aggregate or gravel to further enhance the durability of the pavement. This involves utilizing 6 to 8 inches of thoroughly compacted aggregate as the foundation, followed by 3 inches of asphalt pavement. This base layer serves to distribute the weight of vehicles more evenly across the underlying soil, reducing the risk of future pavement failure.

Consulting with an experienced contractor can help you determine the most appropriate thickness that will meet your needs and provide a long-lasting pavement solution.

Factors to Consider When Determining the Appropriate Thickness for New Asphalt.

  • Expected traffic volume
  • Climate and weather patterns
  • Subgrade conditions
  • Type and size of vehicles
  • Pavement design life
  • Existing pavement condition
  • Availability of materials
  • Budget constraints
  • Local regulations and specifications
  • Environmental impact
  • Future maintenance plans

In addition to the specified aggregate size and thickness, SM-9.5A also requires the use of a specific asphalt binder known as PG 64S-2This designation ensures the desired performance and durability of the asphalt mix.

What Is SM 9.5 a Asphalt?

SM-9.5A is a type of asphalt mix that consists of a fine to medium aggregate size with a nominal maximum size of 3/8 inch (9.5 mm). It’s commonly used as a surface mix and is typically placed at a thickness of 1 ½ inches (40 mm). The “A” designation in SM-9.5A refers to the Performance Graded (PG) asphalt binder required for the mix, which is PG 64S-22.

The use of a smaller aggregate size in SM-9.5A provides a smoother surface compared to larger aggregate sizes. This makes it suitable for applications where a smoother finish is desired, such as parking lots, residential driveways, and low-speed roadways. The finer aggregate also allows for better compaction, resulting in a more durable and long-lasting pavement.

In addition to it’s durability and smooth surface finish, SM-9.5A also offers good skid resistance, which is important for ensuring vehicle safety. The mixs properties are designed to provide adequate friction between the tires and the pavement surface, reducing the risk of skidding and improving overall road safety.

It’s commonly used in a wide range of applications, making it suitable for various project types and locations.

In addition to it’s smooth appearance, the 9.5 mm asphalt mix, also known as SP 9.5mm, is typically used for applications with lighter traffic loads, primarily for car traffic. It can be applied as either a bottom or top lift and is generally placed at a depth of 1″ to 1 ½” per lift.

What Is 9.5 Mm Asphalt Used For?

9.5 mm asphalt, also known as SP 9.5mm, is primarily used for lighter traffic load applications, specifically car traffic only. It’s a structural mix that offers a smoother appearance compared to the SP 12.5 mix. This makes it suitable for projects where aesthetics are a consideration.

When it comes to the thickness of the asphalt layer, the SP 9.5mm mix is typically specified to be placed in 1″ to 1 ½” depth per lift. This means that it can be used effectively as either a bottom or top lift.

If you’re dealing with heavier traffic loads, such as trucks or buses, the SP 12.5 mix might be more appropriate. However, for lighter traffic loads and applications that prioritize aesthetics, the SP 9.5mm mix is often the preferred choice.


In conclusion, the choice between 12.5 mm and 9.5 mm asphalt paving depends on the specific project requirements. Ultimately, considering the intended purpose and the specifications of the project will help determine the right asphalt paving size for a successful outcome.

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