Like tarmac, an asphalt driveway can last more than 30 years, as long as it is properly installed. Should the design procedure be wrongly done, chances are your driveway will become faulty. Its longevity depends mainly on a strong base, the right materials, efficient construction practices, proper drainage, and regular maintenance.
Here are some key points you need to consider as far as the foundation for an asphalt driveway is concerned.
What is a good Asphalt driveway base?
The secret to a long-lasting asphalt driveway is the properly crushed gravel base beneath the asphalt. There are two types of asphalt: the common mix for home driveways which is smoother and a coarser mix for driveways with heavy traffic.
Features of a good asphalt driveway base include:
A good foundation base for an asphalt driveway should have proper drainage to prevent water from pooling beneath the inner layers, leading to cracks and even potholes. So, ensure yours has at least a 2% slope/fall with a fast-draining gravel base within the asphalt layers.
A good paving contractor should never use short-cuts when installing your asphalt driveway. Throughout the construction process, your contractor should pay keen attention to the materials and techniques for the compaction, which largely involves the edges and joints to the tamping of the pavement edges.
Most contractors recommend the usage of a tack coat to prevent the surface from slipping. So, if yours feels unusually smooth, it probably was tacked improperly. Also, mix segregation is strictly prohibited as it increases the likelihood of potholes and pavement mishaps in the future.
The secret to a good asphalt pavement is a robust subgrade and aggregate base. It starts with stabilizing the subgrade. For example, if the soil beneath your home is predominantly clay, it needs to be replaced with stone and a fast-draining gravel base. When left unremoved, the loose soil might compromise the hot mix’s ability to withstand moisture, heat, freezing temperatures, and heavy traffic impact.
The first step towards creating a good foundation is laying down a rock base before embedding the hot mix. It all depends on the thickness and size of the rock. It’s safer to use a 2 or 3-inch top-size rock for the first base. If you use a smaller and less-thick rock, it might not penetrate into the subgrade and stabilize the earth.
Considering the long-lasting nature of asphalt driveways, it is easy to think that they don’t need maintenance. But as long as they come into contact with water, heat, and ice, it’s easier for them to depreciate, regardless of the qualities of the materials used.
Proper maintenance practices involve addressing the drainage features. If your driveway seems unusually warp, call a paving contractor to check if water has softened the subgrade.
The second maintenance practice involves sealing any cracks due to water or foreign materials like debris or motor oil. Besides their unsightly appearance, cracks and potholes reduce the driveway’s longevity factor. A good sealing product should be fuel-resistant and modified with polymers to prevent spills.
Which is the best base for Asphalt driveway?
A thick asphalt surface for your driveway won’t guarantee how long it will last. The asphalt is merely the top dressing that masks the base below the surface. Instead, you should concentrate on the foundation base.
Getting the right base for your driveway depends on the soil conditions in your area. However, you can narrow down your choice to crushed gravel like C-5 limestone and granite C-5. If you can’t access either option, go for recycled concrete called Con-Bit and combine it with the asphalt. These materials have proper-draining qualities, making them perfect for driveways.
When selecting a base material, don’t concentrate on the type and thickness of the gravel base your contractor intends to install under the surface alone. Choose a material that drains well and allows proper compaction. In this case, go for ground coarse gravel with jig-saw surfaces. This allows them to compact and lock together easily. The jig-saw action protects the base from ice formation that may damage the asphalt surface.
Is 2 inches of Asphalt enough for a driveway?
The thickness of asphalt depends on the type of soil underneath, asphalt mix, the impact of the vehicles expected to use the pavement. You don’t expect a public asphalt driveway to have the same thickness as a residential driveway.
For your case, you expect not more than 4 vehicles streaming in and out of your driveway at low speed. So, your driveway should be 2-3 inches thick, unlike an interstate highway which might need a thickness of at least 4 inches.
Are there different grades of Asphalt for driveways?
Asphalt grades vary by region. There are two types: open-graded and conventional asphalt pavement. The thickness of the asphalt driveway heavily depends on the aggregates. For example, the ratio of every layer to the aggregate should be 3:1.
However, the largest-sized aggregates for open-graded mixes can be up to 80% of the layer’s thickness. To make your pavement look visually appealing without compromising its strength, try using different asphalt mixes. For example, you can start with the conventional mix for the bottom layer, then use a thinner layer of a small aggregate mix at the top.
Tips: Things to consider when making base for Asphalt driveway
Whether you’re looking to install asphalt for your driveway for the first time or already have one, there are many things you probably didn’t know.
Here are a few tips to consider when installing your asphalt driveway.
1. Excavating unwanted materials from the subgrade to pave way for foundation rocks and stones
Installing asphalt starts with removing unwanted materials from the existing surface, including concrete, pavers, and even the asphalt itself. The soil underneath should have fast-draining properties to prevent the asphalt from cracking or having potholes due to being pooled in water.
This process requires heavy machinery like forklifts, front loaders, and small bobcats. Some contractors may recycle the old asphalt or concrete and refine them into high-quality materials for future use.
2. Good surface preparation increases its lifespan
This step involves preparing the site for proper drainage through grading and sloping. Then your contractor customizes the subgrade to meet the standards of the driveway’s layout. Here, laser-guided and automatic motor grader tools will come in handy, to ensure the sloping allows water to run off appropriately.
3. Adequate preparation of the sub-base prevents it from winter damage due to thawing
The crushed gravel base beneath the asphalt is the most fundamental part of your asphalt surface. The solid base determines the durability of your driveway, which is why you should select the right base material according to its thickness and composition.
A good sub-base should not only provide a stable surface to hold the new driveway, but also provide a frost barrier to prevent ice or snow damage. When left uncompacted, the sub-base may reduce the asphalt surface’s longevity.
4. Choosing the right asphalt mix guarantees its durability and strength
A good contractor should recommend the best asphalt mix and use his hot mix plant for your driveway. The hot mix is readily available in your local paving stores, but not all of them suit your driveway. It’s safer to go for a mix that guarantees strength and durability. If it can withstand thawing and freezing, go for it.
5. Regular maintenance lengthens your asphalt’s lifespan
Now that you’ve already known that durability is one of the main benefits of an asphalt driveway, it’s easy to assume that your driveway won’t need regular maintenance. Like other driveway materials, asphalt can wear and tear over time, depending on the impact it receives every day, weather conditions, and the quality of materials used for installation. Your asphalt driveway can last more than 30 years if you seal cracks or the entire driveway, each year. Doing so accentuates the appearance of your driveway, without compromising its strength.