Ultimate Asphalt Driveway Paving Guide
Table of Contents
- Asphalt Driveway Overview
- Advantages of Using Asphalt for Driveway Paving
- What is Asphalt Made Of?
- Asphalt Driveway Paving Installation: Quality Matters
- Common Wear and Tear Issues
- Asphalt Driveways: Bottom Line
Asphalt Driveway Overview
Also known as "blacktop", this beloved surface covering is a frequent choice for a wide variety of commercial and residential applications from parking lots and driveways, to interstate highways and airport runways.
When you consider the many benefits of using this smooth, quiet, durable, sustainable, and budget-friendly material, it's not hard to see why so many people choose asphalt as a top-shelf paving option.
Advantages of Using Asphalt for Driveway Paving
Whether you're paving a large or small residential driveway, asphalt should be a serious consideration for several important reasons:
1. Fast Installation Time
Asphalt takes far less time to install than concrete, as it does not require the extensive drying and curing time that is common for concrete installations.
On the other hand, laying a concrete driveway would take roughly twice the amount of time, not to mention the additional time it takes for concrete to set and cure. By contrast, most asphalt driveways are ready to go in as little as 2 days after installation.
Due to its high bitumen content (the sticky black substance inside), asphalt is quite flexible making it an excellent surface for supporting and efficiently distributing load stresses.
In addition, your blacktop driveway can be salted in the winter to help the snow melt faster and provide better traction. By contrast, concrete driveways can sometimes be damaged by certain salts or de-icing agents.
While asphalt driveways tend to develop cracks at a slightly higher rate than that of their concrete counterparts, it is far easier (and much less expensive) to repair cracks in blacktop versus concrete.
Your paving contractor can seal any cracks or fissures in the surface of the blacktop using a specialized sealant or emulsified liquid (known as "sealcoating").
3. Heat Retention During Cold Months
In colder climates, an asphalt surface can really demonstrate its usefulness during the winter months because its dark color absorbs sunlight which makes it retain heat. This causes snow to melt much faster than it would on a lighter colored surface.
This means that if your neighborhood were to get hammered by a major blizzard, the snow would melt quicker on your asphalt driveway than it would your neighbor's concrete driveway.
Hey, who knows – maybe if you let the sun shine long enough, you can cut your snow shoveling duties in half by letting your driveway do its thing.
There is a flip side to this, however: During the heat-drenched days of summer, a blacktop driveway is definitely no friend to bare feet!
4. Highly Cost-Effective
Of all the different paving options there are to choose from, asphalt ranks as one of the absolute cheapest to install (aside from gravel).
And since a blacktop driveway can be installed within a quicker time frame than other paving materials (e.g. concrete paving stones), you'll spend less money on labor costs as well.
The budget-friendly nature of asphalt should not only be considered in terms of its installation cost, but also its low long-term maintenance costs as well.
As mentioned earlier, if your blacktop driveway begins to show signs of cracking, you can simply hire a trusted paving professional to seal those cracks for a reasonably low price.
It should be noted that if you just had an asphalt driveway installed, you should not have any sealant applied until at least six to nine months have passed. Otherwise, you can run the risk of damaging the foundation.
Regular upkeep tasks such as sealcoating (every 2-4 years), sweeping, crack filling, and general maintenance can add several years to the lifespan of your asphalt surface, at a lower average cost than that of concrete.
5. Environmentally Sustainable
It is comprised of several different naturally occurring materials (e.g. sand, gravel, bitumen, etc.) that are renewable, making it a prime candidate for recycling.
With the colossal amount of asphalt that is recycled on an annual basis, economists have estimated that it actually saves taxpayers roughly $1.8 billion per year.
Not only can damaged or out-of-service roads be broken up and recycled into new asphalt, but other post-consumer waste products such as old shingles or used tires can be recycled into new blacktop pavement as well.
This high "recyclability" gives asphalt a virtually unlimited life cycle, as it can be used over and over again in a variety of forms or applications.
What is Asphalt Made Of?
One of the main ingredients in asphalt is a naturally occurring material known as bitumen. This black, gummy, viscous liquid is mixed with sand and crushed rocks (often called "mineral aggregate") to form asphalt.
Bitumen is far from a newly discovered material. In fact, this sticky substance was commonly used in the mummification practices of the ancient Egyptians over 5,000 years ago!
Technically speaking, bitumen is known as a "cementitious" material, which is a fancy way of saying that it acts like cement.
Since bitumen is the primary binding agent in asphalt, it is in heavy demand year-round to the tune of over 100 million tons per year.
So where does all of this highly useful material go?
Perhaps not surprisingly, it is also the most recycled material in the U.S. with over 60 million tons being reused or recycled each year.
Compare that with only 2 million tons of plastic being recycled per year, and you can easily see why asphalt is considered to be one of the most sustainable, environmentally friendly materials in use today.
Asphalt Driveway Paving Installation: Quality Matters
When it comes to installing asphalt paving, quality is of the utmost importance. If the job has been done right, the blacktop will be level, smooth, and neat.
A shoddy job, on the other hand, will be evidenced by rough, uneven, and generally unattractive pavement.
For example, you've probably seen paving jobs where it looked like the blacktop was literally dumped and splattered over a given area, with no clean-cut edges or smooth transitions to speak of.
This type of common occurrence should give us a good idea of the workmanship, technique, and skill level that is required to produce a quality asphalt paving job. There are several steps that your paving contractor will carry out in order to install a high-quality blacktop surface.
Below is a general overview of the process:
1. Preparing the Subgrade Area
If the installation is being performed as a new construction, your paving contractor should take great pains to ensure that the soil subgrade has been adequately prepared, graded and compacted, so that the surface is absolutely level.
This may include removing any loose rocks or stones, as well as "soft" soils such as clay or sand.
That doesn't mean that the ground cannot have any slope, as we know that many driveways and other surfaces do sit at an incline.
But the ground must be level in the sense of not having any dips, bumps, or other surface aberrations that could cause problems once the asphalt layers have been applied.
If your contractor will be extending or expanding upon an existing pavement installation, precision saw-cutting or milling techniques may be used to create a smooth transition between the two pavement surfaces.
2. Building the Subbase and Base
Your paving contractor will then build a subbase and base layer (directly above the soil subgrade) using aggregate material such as crushed stone or gravel.
Normally 4-6 inches thick or more, this will provide solid support for not only the asphalt but for the vehicles that will park or drive upon it as well.
In fact, the entire process requires an extreme level of precision and attention to detail, which is why a job like this is always best left to a trained professional.
3. Drainage Considerations
When it comes to blacktop paving installations, water can be a formidable nemesis.
If the installation is done incorrectly, it will be easy for water to collect on the surface of the pavement which can eventually cause potholes, alligator cracking, heaving (formation of ice crystals in the soil beneath the pavement), or even collapsing of the ground beneath the pavement.
Your paving contractor should make the appropriate considerations for water drainage by ensuring that the pavement has the proper slope and grade to facilitate efficient water runoff.
These considerations may include gutters and curbs that will direct water runoff to the appropriate catch basins or storm drains, in order to avoid potential water damage issues.
All of these factors must be taken into account when planning out a paving installation, showing once again why this type of precise and highly detailed work is best carried out by a qualified contractor.
4. Applying the Asphalt
After the base has been built to exacting specifications, your paving contractor will then begin laying down the asphalt.
This process is done in a series of layers known as "courses", where each layer (or course) must be rolled and then carefully compacted to ensure a smooth, evenly-finished product.
Using specialized equipment, the asphalt is heated to a high temperature in order to make it easier to spread across the surface. If the semi-liquid mixture is allowed to cool too much, it will hinder the flexibility of the asphalt, making it difficult to apply an even course.
The thickness of the asphalt pavement will vary depending on the type of vehicles and loads it will support, as well as the condition and thickness of the subbase.
5. Smoothing Out Transitions
Your paving contractor must not only consider the quality of the surface covering itself, but also how it connects with the streets, sidewalks, etc. that surround it.
The last thing you would want is to have a big "hump" or other pronounced inconsistency in these transitions, as they can not only produce a jarring effect but can also hinder the proper drainage of water from the pavement.
One of the most common techniques that your paving contractor might use to smooth out these transitions is a process known as asphalt or pavement "milling", which involves removing and reshaping part of an existing paved surface using a specialized piece of equipment.
6. Applying the Surface Course
This final roll is designed to create a smooth surface that is free from protruding aggregates or other surface irregularities that can hinder the pavement's functionality.
Once this final layer has been applied and the asphalt has time to dry and settle, your pavement installation will be ready for use!
Asphalt Driveway Paving: Common Wear and Tear Issues
As the law of entropy would have it, all asphalt surfaces are subject to wear and tear over time. Many of these issues appear gradually and are nothing out of the ordinary, while others might come rather unexpectedly.
In either case, the most common telltale sign that wear and tear is occurring is when cracks begin to emerge.
Below are some of the most common culprits for cracks in blacktop pavement:
1. Improper Installation
Of all the reasons why asphalt defects can occur, this one has to be the number-one culprit.
One of the most common mistakes made by inexperienced or subpar paving contractors is not adequately compacting the foundation before laying the asphalt.
When this happens, the courses that are laid on top of the foundation don't get the support they need, which will eventually result in cracking and uneven "pockets" developing in the blacktop.
If the pavement begins to display cracking within the first two years of being installed, this is a sure sign of poor installation practices.
2. Ultraviolet (UV) Rays
Asphalt can take a beating from the sun, especially in very hot or arid climates. Interestingly enough, it's not so much the heat from the sun that causes problems for asphalt; rather it's the UV rays that do most of the dirty work.
This natural form of radiation emitted by the sun can zap the moisture right out of asphalt, drying it out and diminishing its natural flexibility.
Your paving contractor has all the tools and equipment necessary to perform this task, so be sure to ask them about this much-needed routine maintenance.
3. Changes in Soil Composition
Not all soil is created equal; some parts of the world have rich soil with a moist composition, while other areas have soil that is mostly comprised of sand or clay.
In areas where the soil composition has a high clay content, you will more than likely have more trouble with an asphalt installation.
The reason for this is that the clay goes through shrinking and expansion cycles due to changing weather conditions. For example, if a particular area is hit with a prolonged drought, this will cause the clay to dry up and shrink.
Once the rain finally comes, the clay will then swell up and expand. This can wreak havoc on pavement by constantly shifting and moving the ground beneath it, eventually weakening the structural integrity of the pavement. Once this happens, cracks are virtually inevitable.
4. Soil Erosion
Soil erosion is a common occurrence in areas where the paved surface is lower than the terrain that surrounds it.
When this occurs, runoff from rainwater will eventually saturate the soil that surrounds the pavement installation, causing water to seep underneath the pavement and disturb the foundation.
5. Damage from Tree Roots
You have to admire Mother Nature, especially when something as unassuming as a tree root can exert enough pressure on pavement to eventually cause cracking or other surface disruptions.
This scenario is quite commonly seen in driveways although sidewalks, streets, and even parking lots can experience damage from tree roots as well.
6. Excessive Weight
One of the first factors that a paving contractor must consider is the type of loads that a paving installation will support. For example, it's obvious that an airport runway designed to support 400-ton jumbo jets is going to need a much stronger foundation than a residential driveway.
7. Freezing and Thawing Cycles
The earth beneath your driveway is not a static thing; it's constantly changing and can be materially affected by factors such as temperature and humidity. This holds especially true in terms of freezing and thawing cycles.
Every time the ground beneath the pavement freezes or thaws, it contracts or expands which can cause the pavement to move or shift. If water penetration happens as a result of these shifts, the damage from cracking can worsen over time.
While there's no way to prevent 100% of the wear and tear that your asphalt pavement might endure, our qualified paving contractors can help you maximize the lifespan of your blacktop through professional installation techniques and proven repair methods.
So whether you're dealing with a cracking problem that came from excessive UV exposure or a pesky tree root, our contractors can get your asphalt installation looking great again!
Asphalt Driveways: Bottom Line
There are dozens of asphalt paving contractors out there, but not all of them provide the same level of service, expertise, and workmanship.
Our trusted contractors understand that the needs of every customer will be different, and they are willing to take the time to thoroughly assess your paving project so that they can make the most appropriate recommendations.
Whether you have a residential, commercial, or industrial project to take care of, you can rest assured that we will connect you with a qualified and experienced contractor to handle the job.
Contact us today to see how we can help you create a stunning asphalt driveway that will stand the test of time.
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