Modern asphalt pavement is a mixture of stone aggregate and mineral filler such as crushed rock, sand, gravel, slags, and recycled materials.
That mixture is combined with a small amount of heated asphaltic cement binder to form a cohesive surface mix suitable for roadways, parking lots, and driveways. With proper asphalt paving and maintenance, an asphalt surface should last 30 years or more.
Types of asphalt
Porous Asphalt
Porous pavement is composed of a thin layer of asphalt poured over a base of aggregate. It is a cost-effective pavement solution that would last for more than two decades with proper asphalt paving and maintenance.
Porous pavement is excellent for rainy areas, parking lots, and paved surfaces requiring adequate drainage. Porous pavement is often used in parking lots to allow the water to drain through the pavement after heavy storms.
Perpetual Pavement
A perpetual pavement uses a multi-layer durable design process that provides a smooth, safe, and long-lasting surface. The perpetual pavement base is a flexible layer that absorbs wear and tear.
It has a solid middle layer which supports stability, while the smoother top layer of asphalt mix is designed for heavier traffic. The perpetual pavement is effective for quick patch and repair suitable for roads that can’t be shut down for long construction projects.
With the proper asphalt paving and maintenance, you can enjoy a perpetual pavement for at least 50 years.
Quiet Pavement
Quiet pavement is one made of a stone-asphalt mix that reduces noise pollution by traffic.
Warm Asphalt mix
Warm asphalt mix is manufactured at a lower temperature, 50 to 100 degrees cooler than hot mix asphalt.
The manufacturing process reduces fuel consumption and greenhouse gas generation. It is an appropriate mix to add reclaimed asphalt pavement to, which can provide better durability with regular asphalt paving and maintenance.
Thin Overlays
Thin overlays are thin asphalt pavement layers that preserve a pavement by being positioned over existing asphalt paved surfaces.
If there are minor imperfections, thin overlays can help cover them up and improve its appearance.
Additionally, a thin overlay can boost the quality of ride, decrease distress and noise level in the pavement, and improve life-cycle cost by preserving pavement ‘s top shape for years to come with regular asphalt paving and maintenance.
How is asphalt pavement installed?
1. Remove the existing pavement surface.
The first step in installing asphalt pavement is the removal of the existing surface.
No matter how much scheduled asphalt paving and maintenance is performed, these surfaces are often older asphalt, concrete, or paving stones.
Usually, a reputable paving team will begin the demolition process to remove all of the existing surface, providing a clean canvas for the new asphalt. Removing the paving surface requires forklifts, bobcats, front loaders, and dump trucks.
2. The Grading and Sloping Process
Once the demolition process has begun, and the existing surface has been completely removed, the pavers can begin the grading and sloping process.
The grading and sloping steps help to create a pavement that boasts excellent water drainage in the event of high rains.
Depending on the company you hire to do your asphalt paving and maintenance, pavers will usually use automated laser transits and motor graders for the best outcome.
Since water is the primary source of damage to asphalt, grading and sloping should be done with precision and carefulness.
3. Prepare the Sub-Base
As soon as pavers have created a surface that yields excellent water drainage, it’s time to prepare the sub-base. In asphalt roadways, driveways, etc., the sub-base gives support to the new pavement.
Additionally, the sub-base provides a frost barrier for the winter season.
The frost barrier helps reduce the likelihood of sustained damage during winter’s harsh temperature. During the prep phase, workers have to carefully measure the thickness of the sub-base, its stability, and compaction.
If the measurements don’t line up, it can cause the asphalt surface not to be as durable as it should. No amount of asphalt paving and maintenance can make up for a poorly prepared sub-base.
4. Sub-Base Repair
As the sub-base is compacted to the proper standard, the pavers will execute what is known as a “proof roll.” A proof roll secures the underlying surface to ensure that it’s strong enough to hold up the top layer of asphalt. If the pavers find a spot that is not sturdy during the proof roll, they will take the necessary steps to repair the sub-base.
5. Binder and Surfacing
Once the sub-base has been adequately repaired for any weak spots, the pavers can start the binding and surfacing. The binding agent is usually made of aggregate that’s mixed with oil. The mixture makes the binder industrial-strength and sturdy to withstand asphalt paving and maintenance.
6. Install the Asphalt
After the first five steps are completed with precision, the pavers can install the top layer of asphalt.
If the old asphalt meets with new asphalt ends, butt joints should be installed to ensure a smooth transition between both pavements. Once complete, the whole surface is smoothed and compacted down.
Once all steps have been completed, the new asphalt will boast smooth driving and years of durability with the proper asphalt paving and maintenance.
Proper maintenance for asphalt surfaces
A proper asphalt paving and maintenance program includes crack filling, pothole repair, sealcoating, and many other surface applications, depending on the pavement condition. It should also involve sweeping and periodic line striping.
Three main types of asphalt pavement maintenance:
1. Preventive Maintenance:
This type of asphalt paving and maintenance is the most effective to extend pavement life cost-effectively. Preventative maintenance is a way to ensure the effectiveness of surface treatments when the asphalt is in fairly good condition.
From crack sealing small cracks to seal coating parking lots, preventive maintenance addresses minor issues before they become serious issues.
Pavement Sweeping: Regular sweeping protects the pavement. Sand and grit that accumulate over time are abrasive and will eventually wear away the surface.
Crack Sealing: Cracks should be the first thing addressed when scheduling maintenance. Cracks ¼ inch or larger should be cleaned with high-pressure air and then sealed with a hot rubber crack sealer fortified with polymer.
Seal coating: Protective seal coating will significantly extend the life of pavements. Seal coating is critical for eliminating the damaging effects of the sun, oxidation, and water.
2. Corrective Maintenance:
This type of asphalt paving and maintenance is performed when the pavement needs repair and is usually more costly. Repairs could be structural overlays, mill, overlays, minor pothole repair, patching, rutting ,or extensive cracking. Corrective maintenance is also termed “reactive” maintenance.
Asphalt Repairs: Surface repairs can involve a thin overlay of compacted hot mix being applied to fill low areas or to replace lost surface fines. This process is also known as “skin patching” and is an essential part of asphalt paving and maintenance.
Asphalt Removal and Replacement: Removal and replacement are recommended for areas exhibiting base failure or “alligatoring.”
Alligator Cracking is a pattern of interconnected lines or cracks that signal structural failure.
This cracking typically begins as lengthy cracks, which will eventually spread and deteriorate into alligator cracking. Like rutting, cracking comes from a surface or base that is too thin or weak layers of top asphalt, base, or subgrade.
If it is caught early on in the asphalt paving and maintenance cycle, cracks can often be filled with crack seal material and seal coated to protect against moisture. Once cracks deteriorate to Alligator Cracking, the only accurate repair is removing the asphalt and base and repaving.
This process involves saw cutting and removal of the distressed area. The base material is then either recycled or replaced and a new compacted hot mix
asphalt completes the job.
Asphalt Overlay: An asphalt overlay is simply the process of installing a new surface layer. A hot mix asphalt layer is laid directly over existing asphalt on either parking lots or roads.
Pavement should be relatively sound to be a candidate for an overlay due to regular asphalt paving and maintenance without large areas of base failure.
Fabric Overlays: Fabric overlays form a barrier between the existing surface and the asphalt, protecting the sub-grade from water intrusion, reducing asphalt paving and maintenance costs, and extending pavement life. If the pavement condition has deteriorated to requiring an overlay of new asphalt, an inner layer of fabric should be considered.
Milling: Milling is the process of removing a selected, precise thickness of asphalt pavement with a large rotating drum that grinds up and removes the surface. Milling is recommended when an asphalt pavement’s deficiencies are primarily surface distresses. Milling may offer an effective solution in addition to regular asphalt paving and maintenance. Once the milling is removed, the asphalt is often recycled as aggregate in new pavement.
3. Emergency Maintenance:
Emergency asphalt paving and maintenance is performed during an emergency, such as a blowout or severe pothole that needs repair immediately for safety reasons or to allow traffic to utilize the roadway or parking lot.
Emergency maintenance also describes temporary treatments designed to hold the surface together until more permanent repairs can be performed.
Proactively planning preventive asphalt paving and maintenance is the best way to prevent costly corrective or emergency maintenance.
Advantages of Asphalt Pavement
- The majority of communities and government agencies prefer asphalt pavement for their roads because of its durability and performance during heavy traffic conditions with regular asphalt paving and maintenance.
- Asphalt also has excellent waterproofing, flexibility, and adhesive properties to bind and hold the pavement’s aggregates. Asphalt has been widely used for paving and road construction.
- Asphalt pavement is eco-friendly, safe, and tolerates a range of temperatures and weather conditions.
- Asphalt is used more frequently than other surface types because it is more cost-effective with regular asphalt paving and maintenance.
Disadvantages of asphalt and common issues
- Asphalt is a complex mixture of thousands of chemicals. Asphalt’s characteristics provide easy access to weather, salts, and other chemicals to attack and disintegrate the asphalt molecules. As the asphalt molecules disintegrate, the pavement loses much of its original properties, such as binding and waterproofing. Regular asphalt paving and maintenance can help counteract the weathering and disintegrating effects.
- Moisture is the biggest enemy of asphalt. Once it seeps into the foundation, it can wash away critical pavement components over time that make up asphalt and keep it strong.
- Freezing and thawing will cause some shifting in asphalt and, as the snow melts, it causes moisture, asphalt’s primary enemy.
- Motor oil, diesel oil, and grease contain petroleum that can weaken and penetrate asphalt. Weakening leads to structural breakdowns of asphalt followed by cracking. This situation can be avoided by cleaning up oil and grease spills as soon as possible during asphalt paving and maintenance.
The cost of paving and maintaining an asphalt surface
Your location and the type of asphalt surfacing project you need done, such as installation, repair, or repaving play a role in determining an asphalt surface’s final cost.
If you are planning to pave a new asphalt surface, you can expect to pay between $3 to $4 per square foot.
The entire cost of an asphalt pavement installation also includes construction, working, time, and other project factors. The final price would consist of ripping out the existing pavement, hauling it away, and doing other work that the area needs before laying down the asphalt mix.
Repairing or repaving asphalt paving and maintenance does not cost as much as a total installation. Service costs for the asphalt pavement on a repaving project would cost about $1.75 to $2.25 per square foot.
Asphalt pavement surfaces that are properly maintained by regularly scheduled asphalt paving and maintenance can last over 20 years. Even if a patch, repair, or repaving service appears costly initially, it would likely extend the life of your road or paved surface. If your parking lot or road needs replacing, you will often only need to repave the top layer of asphalt for it to look new again.