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Can You Put Asphalt Over Concrete?

 

Putting asphalt over concrete may be possible, but only in certain conditions. Successfully paving over concrete depends heavily on the climate, underlying concrete, traffic load and installation. Ultimately, it’s important to understand the situations in which asphalt can effectively be laid over a concrete surface and when it’s better to consider other options.

 

If you’re considering laying asphalt over a concrete driveway, think about hiring a professional paver to handle the project. Putting blacktop over concrete can lean either way depending on the circumstances, so it’s best to get a professional opinion.

 

Things to Consider Before You Put Blacktop Over a Concrete Driveway

 

While paving blacktop over concrete is a common technique used to create several types of roads, is it the right technique for your driveway? There are several long-term maintenance requirements you’ll likely need to be prepared to cover if you go this route. 

 

The biggest consideration you’ll need to make is how the stability of the concrete will affect the condition of the asphalt. This will vary depending on the climate, current condition of the concrete and other factors.

 

Pros and Cons of Asphalt Over Concrete

Before paving blacktop over your concrete surface, be sure you’ve considered all the downsides and side effects associated with this technique. Asphalt may work well and have some benefits, but it also has some drawbacks to be aware of. By understanding the differences between asphalt and concrete and their pros and cons, you can make an informed decision.

 

When done correctly and under the right circumstances, pouring asphalt over your concrete driveway can be beneficial in several ways, including: 

 

  • Easier to repair: When it comes to minor damage, asphalt is usually easier to fix than concrete due to its flexibility.
  • Attractive aesthetic: If curb appeal is on your list, asphalt can elevate your property by providing a smooth, dark and sleek appearance to your driveway.
  • Quicker installation: Unlike concrete, asphalt is faster to install, especially when the weather’s mild in Central PA. You can enjoy minimal disruption and downtime to your driveway.
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Though it has some advantages, putting asphalt over concrete also has drawbacks. Consider the long-term implications and costs involved with the following:

 

  • Climate-dependent: Asphalt is softer than concrete, making it more flexible to Central Pennsylvania’s freeze-thaw cycles. However, if the underlying concrete is in bad condition, it can impact the asphalt, potentially leading to cracks.
  • Reflective cracking: Pouring asphalt over concrete won’t mask any existing cracks — they’ll eventually surface, leading to more deterioration.
  • More maintenance: Asphalt is easy to maintain, but with a damaged or cracked concrete base, it may require more costly upkeep.
  • Underlying concrete issues: Putting asphalt over concrete won’t address any underlying concrete problems. These will eventually need tending to, contributing to issues down the line.
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Longevity

Paving asphalt over concrete can offer good longevity, as long as the concrete base is secure. States in the northern part of the country are more likely to use asphalt due to its ability to withstand the constantly changing climate conditions. Concrete use can result in cracks and shifts, but this is not because of paving mistakes — it’s from temperature change.

 

If you are looking to pour asphalt over concrete, it’s important to know that professionals must create a uniform base, clean and mill the concrete to ensure the asphalt overlay will have a good bond with the concrete. After milling, professionals will use proper adhesives and hot mix asphalt to correctly bond the asphalt over concrete.  

 

Will Asphalt Crack if It’s Laid Over Concrete? 

 

Asphalt can crack if it’s poured over concrete. An unstable concrete base can become compromised from the gradual cracking of concrete as it moves and shifts from the environment around it, with factors including:

 

  • Traffic
  • Temperature fluctuation
  • Freezing and thawing of ice and snow

 

When pouring asphalt over concrete, the asphalt’s lifespan is determined by the quality and integrity of your sub-base, which in this case would be the concrete. If there are cracks in the concrete or you have an uneven base, your asphalt driveway or parking lot can be compromised and crack where your concrete is cracked. 

 

One of the biggest concerns of putting asphalt over concrete is that the condition of the asphalt often depends on the condition of the concrete underneath it. If you don’t have a good foundation to build on, you will be running into trouble down the road with your driveway or parking lot.

 

Preventing Cracking

 

To prevent the concrete from cracking and shifting, expansion joints are measured out no farther apart than two to three times the total thickness of each concrete slab. For example, if the concrete slab is 4 inches thick, the expansion joint should be between 8-12 feet apart. These expansion joints are most commonly made from rubber, metal or braided materials like stainless steel. 

 

After the concrete is poured with proper expansion joints, the asphalt can be poured on top of the concrete if you want that solution.

Benefits of Removing Concrete First

Removing old, cracked or unstable concrete first lets you start fresh with a strong foundation, which benefits the final result. Even if the concrete appears healthy on the surface, there’s no way of knowing its true state without removing it.

 

As asphalt generally reflects what’s underneath it, consider the following benefits of removing concrete first, which could save time and money over the long term.

 

Creates a Structurally Sound Base

Older concrete that is cracked from the expansion and contraction of freezing and thawing ice should be removed and replaced before you pour asphalt. It is best to start from the ground up to ensure you have a structurally sound base. The quality and integrity of your driveway or parking lot can suffer if your concrete is not removed or replaced first.

 

You’ll Know What’s Going on Under the Base

Another reason to remove your concrete is to find out what is under the base of your current driveway. It could be sunken or shifted, revealing holes where water and ice can form, ruining your base of concrete. Sometimes it’s best to have the existing surfaces excavated so you can start fresh with a reliable sub-base.

 

Asphalt Is Easier to Install and Maintain

Using asphalt for new driveways is often a better choice than using solely concrete for a few reasons. Asphalt can be flexible with temperature by contracting and expanding in warm and cold weather, since it is not a compact surface like concrete. It is much more affordable to install and maintain while having a fast installation time, so overall it is more economically efficient and cost-effective than solely using concrete.

 

Asphalt driveways with a proper, stable base may require less maintenance in the long run. Pouring asphalt over concrete can be cheaper in the short term, but you will have to spend money to fix and maintain it, costing more money over time. Digging up the concrete and laying asphalt may be expensive at first, but can save you money in the long run due to asphalt’s longevity and low maintenance needs.

 

Boosts Curb Appeal

Using primarily asphalt allows the surface to last longer and maintain its appearance. Your driveway is in the front of your property, and is one of the first things passersby see, no matter how narrow or wide it is. Unstable or worn concrete underneath the asphalt will eventually affect the appearance of your driveway, potentially showing cracks, slits and unevenness, depending on the concrete. Asphalt with a strong base provides a smoother outcome, boosting your home’s value and appearance. 

Discuss Putting Asphalt Over Concrete With CMI Paving

For the most educated and well-informed decision, consider having a pavement professional inspect your concrete surface. At CMI Paving, we have over 40 years of paving experience, reinforcing driveways with durable asphalt suited to Pennsylvania’s climate. 

 

We want our customers to have the correct information so they can make the right decisions when hiring professionals to pave their driveways or parking lots. Consider discussing your options with us to decide whether to pave blacktop over your concrete driveway or replace it. Don’t look anywhere else for professionals to newly install, repair or replace a driveway in Central Pennsylvania and beyond.

 

From residential and commercial paving to excavation work, we have the professionalism and expertise to answer your questions and deliver results that will satisfy your needs. Contact CMI Paving for a free estimate to discuss the possibility of laying asphalt on top of concrete.

 

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