The use of asphalt pavement is widely popular in construction projects involving residential and commercial properties. Due to its durability to withstand external elements like heat, hail, ice, and rainfall, it has a long life span, lasting upwards of 25 years with regular maintenance. As a result, it is a common fixture in our daily lives, being used for our roadways, parking lots, and roofing materials. If you are a residential or commercial property owner, knowing how the asphalt pavement installation process works step-by-step is beneficial to proper maintenance and repair.
1. Removing Existing Asphalt via Demolition
The first step in the asphalt installation process is to remove the old, existing surface. The most commonly removed materials are concrete, pavers, and worn-out asphalt that is no longer functional.
If the area that is being re-done is large enough, small to large machinery like bobcats, forklifts, front loaders, and dump trucks may be used to break up and remove the old debris. To minimize as much waste as possible, the existing surface is recycled by DCPLM into reusable, new asphalt for future projects.
2. Grading and Sloping Installation Area
With the area clear, the next step is to prepare the surface for proper water drainage by testing water runoff direction.
- The area is strategically sloped to ensure your asphalt’s structural strength remains intact, and grading is used to make the asphalt porous enough to prevent water collection.
- This process is done with automatic motor graders, and laser-guided transits.
This step is vital, as improper water drainage leads to asphalt heaving, cracking, and pothole damage.
3. Preparing, Creating, and Compacting a Sub-Base
To ensure that your asphalt pavement has the support it needs to withstand inclement weather, and heavy vehicle impact, a strong sub-base is required.
- The sub-base layer acts as a frost barrier, reducing winter damage that occurs from the freeze-thaw cycle of the winter-spring months.
- It also works to reinforce your asphalt pavement, preventing it from buckling under pressure, or from forming depressions or dips.
For the sub-base to be strong, proper thickness, and compaction are needed to secure it in place.
4. Proof Rolling to Identify Weak Spots in Sub-Base
Now that the sub-base is graded, sloped, and compacted, DCPLM proof rolls the surface to identify any weak spots. This involves:
- Taking a loaded quad-axle dump truck, and rolling it over the entire sub-base surface area, inch-by-inch, to ensure that it is strong and flexible.
- If any of the sub-base layer begins shifting, dipping, or flexing by more than an inch under the quad-axle truck, then it means that the sub-base layer requires additional reinforcement before the asphalt can be installed.
When there are weak areas found in the sub-base layer, DCPLM will either:
- Repair using the traditional undercutting technique, which involves digging down 2-3 feet and replacing the soft soil with aggregate material.
- Dig 16 inches down, and lay down a geo-grid to connect the bridge base materials together.
- Use a technique called plowing, which still involves undercutting the sub-base layer, but instead of removing the soft soil, we just mix in added aggregate to strengthen the compromised area.
5. Asphalt & Sub-Base Binding
Once the proof roll reveals that the sub-base layer is strong and supportive enough for the asphalt pavement installation, a binder is applied. This binder is what gives the new asphalt pavement installation its strength. It is composed of an aggregate base, mixed with oil.
6. Laying Down the New Asphalt Surface
After 24-48 hours, the sub-base layer and applied binder should be completely cured, creating a solid foundation. Now, a fresh layer of asphalt is added on top to create that smooth, jet-black finished surface you are used to seeing on roadways, and parking lots. The surface asphalt is composed of bitumen (binding agent), oil, and sand.
7. Smoothing Out the Surface With Butt Joints & Transitions
On most properties, the asphalt pavement installation will connect to existing roadways, parking lots, or driveways. This means that the transition from new to old must be made smooth. This is done with butt joints, and graded transitions, to ensure that pedestrians don’t notice the difference between the old and new asphalt surfaces.
Wrapping It Up: The Final Roll Over
After all the butt joints and transitions are laid out, a roller truck is used to ensure that the new asphalt pavement installation is compact and smooth. This ensures that there are no aggregate bumps or stones left poking through the new surface.