Q: Is it OK to Pour Concrete Over Asphalt?

• <div><p>You can pour concrete over asphalt if it&rsquo;s in good condition, thick, stable, and well-compacted. Concrete is more durable than asphalt and can extend the lifetime of your driveway without having to pay frequent <a href="https://www.angi.com/articles/asphalt-driveway-repair-cost.htm">asphalt driveway repair costs</a> or replace it completely. </p><p>But this is best reserved as a temporary solution based on budget restraints, as asphalt requires more frequent repairs and assessments than concrete. Once that concrete top is poured, it&rsquo;ll be harder to accurately understand what&rsquo;s happening beneath that layer, which could lead to more issues.</p></div>

Question 1

Which gravel can you harden into a solid surface?

Accepted Answer

•

Decomposed granite and caliche can both harden into a solid surface using a plate compactor. However, due to decomposed granite’s fine particles, it’s not suitable for driveway surfaces. Some homeowners use pea gravel mixed with a gravel-binding resin to bind the loose stones and create a solid surface that won’t shift like loose gravel.

Question 2

What is the lifespan of asphalt pavement?

Accepted Answer

•

You can expect your asphalt pavement to last anywhere from 20 to 30 years, or 25 years on average. The life expectancy of your asphalt driveway depends on the climate, the amount of traffic, and how well you maintain it. While you can’t necessarily control some of these factors, you can control the amount of maintenance effort you put into your driveway.

To prevent your asphalt from deteriorating prematurely, you should follow a good maintenance routine involving regular cleaning, reparation work, and resealing.

Question 3

What’s the difference between asphalt and blacktop?

Accepted Answer

•

While blacktop is a type of asphalt, the terms should not be used interchangeably, as not all asphalt qualifies as blacktop. The primary differences are in their composition, production process, and ideal applications. Blacktop contains more stone than other types of asphalt and is heated to a higher temperature during production—300°F or more—while hot-mix asphalt is heated to between 275°F and 300°F. The ratio of bitumen (a tar-like crude oil) is a key differentiator, though sources vary: some state blacktop has less bitumen, making it less durable, while others claim it has a higher ratio. Due to these differences, asphalt is generally more durable and better for high-traffic areas like highways and streets, while blacktop is more suitable for playgrounds and residential driveways. For a driveway project, it is best to consult a professional to determine the most appropriate material.

Question 4

How long does recycled asphalt take to harden?

Accepted Answer

•

It takes recycled asphalt 48 hours to initially harden and up to 3 months to fully cure. It’s best to stay off of recycled asphalt for at least 48 hours, then you can walk or drive standard vehicles on it. Hold off on driving heavy trucks or equipment on it for at least 7 days. Allowing the surface to melt together and harden ensures that the surface stays durable and long-lasting.

Question 5

Is it OK to Pour Concrete Over Asphalt?

Accepted Answer

•

You can pour concrete over asphalt if it’s in good condition, thick, stable, and well-compacted. Concrete is more durable than asphalt and can extend the lifetime of your driveway without having to pay frequent asphalt driveway repair costs or replace it completely.

But this is best reserved as a temporary solution based on budget restraints, as asphalt requires more frequent repairs and assessments than concrete. Once that concrete top is poured, it’ll be harder to accurately understand what’s happening beneath that layer, which could lead to more issues.