Pavement Grading Services: An Introduction to a Crucial Step in Pavement Construction

American culture is filled with advice to “build on firm foundations” and stories of what happens to “castles built on sand.” Pavement is no exception. Site preparation is incredibly important, and pavement grading is one of these vital steps.  

At General Pavement Services (GPM), we have over 30 years of experience with site preparation and grading. In this blog, we’ll walk with you step-by-step through what pavement grading is, its importance, and the various grading services available.

Let’s dig in!

Pavement Grading Services: An Introduction to a Crucial Step in Pavement Construction 2

What is pavement grading?

Grading is the first step in building a solid foundation for the road, parking lot, driveway, or other surface you want paved. It involves adjusting the slope, elevation, and smoothness of the ground to make it suitable for the foundation. Here’s how it works. 

1 – Site Inspection and Survey

Before pavement grading begins, the site needs to be inspected and surveyed. Workers will assess the existing topography, soil conditions, and drainage patterns and look for any potential obstacles like large boulders or foliage. 

2 – Clearing and Excavation

Unwanted materials like vegetation, large rocks, and other debris are cleared from the site. If the site is paved but wasn’t properly graded, this step will include removing the old pavement and foundation. Excavation may also be necessary to remove excess soil and create a uniform subgrade.

3 – Subgrade Preparation

The subgrade is the native soil or compacted fill material that serves as the foundation for the pavement. It is crucial to ensure the subgrade is stable, well-compacted, and has the correct slope so water will drain correctly. 

4 – Establishing the Grade and Slope

Engineering plans consider factors like water runoff, accessibility, and overall functionality and use this information to determine the appropriate grade for the site. Grading equipment is then set to achieve the desired slope and elevation for the pavement. Grading is typically done using heavy equipment such as bulldozers, graders, and compactors. These machines cut, fill, and level the surface according to the design specifications.

pavement grading helps with water runoff

5 – Compaction

Proper subgrade compaction is essential to ensure stability and prevent settling. Compactors compress the soil, reducing air voids and increasing the load-bearing capacity. Sloppy compaction can be disastrous, resulting in the pavement shifting and cracking. However, when done correctly, compaction provides a steady base for years to come.

6 – Fine Grading

Once the subgrade is prepared, fine grading is done to create a smoother surface. This involves making precise adjustments to meet the specific requirements needed for the pavement.

7 – Final Inspection

Before paving commences, a final inspection is conducted to ensure that the graded surface meets all specifications and is ready to apply asphalt or other paving materials.

Quality control measures are needed throughout the pavement grading process to verify that the grade, slope, and compaction meet the required standards. This may involve on-site inspections, measurements, and adjustments as needed. Proper grading also ensures adequate drainage to prevent water from accumulating on the paved area. Depending on the project location, workers may create artificial slopes and channels to direct water away from the road or parking lot.

Now that we’ve discussed grading, let’s look at its role in asphalt installation.

What role does grading play in asphalt installation?

Grading is a foundational step that sets the stage for a successful and long-lasting pavement. Here’s why.  

Subgrade Preparation:

Grading ensures the subgrade is stable, well-compacted, and has the proper slope. This is essential for providing a solid foundation to support the weight of the asphalt and the traffic. It will also prevent uneven settling, as discussed earlier.

Water Drainage:

Have you ever been driving after a rainstorm, suddenly hit a large puddle, and felt your car hydroplane? Water pooling on roads and driveways can be dangerous and cause accidents. It also creates cracks and potholes in the pavement. Proper grading helps create a sloped surface, ensuring good water drainage, longer-lasting pavement, and safer travel in rainy weather. 

Smooth Surface:

Fine grading is one part of the grading process and focuses on creating a smooth subgrade surface. This fine surface is essential for an even distribution of the asphalt layer, resulting in a more durable and aesthetically pleasing pavement.

Transition Zones:

Grading is especially important in transition zones where the new asphalt meets existing surfaces like roads, sidewalks, or driveways. It ensures a smooth and seamless connection, preventing bumps, ruts, or other hazards from forming.

pavement grading is important in transition zones where pavement meets other pavement

Compaction Support:

Pavement grading facilitates proper compaction of the subgrade. Adequate compaction is crucial for the stability and load-bearing capacity of the pavement.

Elevation Control:

Grading helps control the pavement’s elevation. Design specifications determine the elevation and ensure compatibility with surrounding structures and surfaces like roads and driveways.

Why is pavement grading so important?

There are two big reasons why grading is vital to any successful paving project. 

First, grading ensures good water runoff. Water is the primary cause of damage to pavement projects. In ideal conditions, water runoff should happen quickly but should be controlled. As we’ve discussed, any accumulation can lead to pavement damage, typically cracks, heaving, potholes, and sinkholes. 

Second, grading is needed for transitions between new and existing pavement. Existing pavements, such as streets, sidewalks, or driveways, usually surround a pavement project. Grading at these transition points should manage water flow and facilitate a seamless shift between surfaces, creating a safe, smooth change between them.

It’s clear: grading is vital in every pavement endeavor to guarantee both efficiency and effectiveness in the project’s overall performance.

Grading ensure pavement effectiveness

What are some grading services in the asphalt world?

There are seven grading services available. These include: 

  1. Rough and Fine Grading: Rough grading involves initial adjustments to the terrain, leveling, and shaping the ground to prepare for more detailed work. Fine grading follows this, refining the surface with precision adjustments to meet specific smoothness and slope requirements. It’s crucial that both rough and fine grading meet local and state requirements.
  2. Grubbing and Land Clearance: This involves digging out roots and rocks (grubbing) and hauling away debris.
  3. Site Preparation: Stabilization and compaction are completed before any paving starts.
  4. Demolition/Excavation: Old pavement, large objects, or structures are demolished or excavated.
  5. Compaction: Multiple rolls drive excess air and water out of the sub-base.
  6. Undercutting and Geo Grids: Soft spots in the sub-base are firmed up through undercutting and geo grids.

Drainage Assurance: This step ensures the maintenance of correct elevation and stormwater retention.

Conclusion

We hope you found this blog informative and helpful! If you did, you might also enjoy the following articles: 

If you have a paving project near our California locations, consider working with General Pavement Management! GPM offers various services, including: 

GPM is committed to going the extra mile to provide quality service and products, including a warrant double the industry standard. If you have additional questions or are ready to start your project, contact us today