Why Is Drainage So Important For Asphalt Pavements?

Learn why drainage is so important for asphalt pavements.

Learn why drainage is so important for asphalt pavements.

Flooding in parking lots and on other asphalt surfaces can be a huge safety concern since it can cause dangerous conditions for both drivers and pedestrians. Water is also a big problem for the asphalt itself. Water can cause serious damage to the pavement from all sides. Continue reading to learn more about why proper drainage is vitally important for your asphalt pavement.

Water Causes Damage From Above

Water can damage asphalt from all directions. From above, it destroys the asphalt over time by breaking down the bonds between the rocks and sand and the asphalt binder. This binder is an oil byproduct and just like in the kitchen oil and water don’t mix. This means that water sitting on the surface of your asphalt can cause huge problems when it doesn’t drain away effectively.  

Draining Water Above

The slope of pavement is the biggest factor in draining water before it can pool on the surface. Asphalt pavement should have at least a 1% slope so that the water can flow away. If you already have your pavement installed without enough slope, work on maintaining it by sealing cracks and patching potholes so that the water that isn’t draining does less damage.

Water Causes Damage From Below

From below, water can wash away the subsoil and weaken the supporting material so that the asphalt cracks under pressure. This usually happens where there isn’t adequate drainage so that the ground gets saturated.

Draining Water Below

Depending on the soil under your pavement, you may need to approach subsurface drainage differently. In some cases, a class-5 aggregate base will be enough to allow proper drainage. In others, you may need to install a 12-18” drainable sand layer below that aggregate base, especially in heavy clay soil. Alternatively, you could install drain tile below the pavement, including a channel to funnel the water away to the storm drain systems.

Winter Water Damage

Finally, during winter, water produces even more problems for your asphalt. It can get into cracks that are already there and worsen them through the freeze-thaw cycle (where freezing causes the water to expand and enlarge the crack, then it melts and slips further down to do it again). Water can also freeze in the layer below the asphalt, causing it to heave upwards and crack. Both of these should be helped by employing the drainage solutions mentioned above, since there should no longer be any pooling water there to freeze.

Need Help Preparing Your Pavement? PTG Enterprises Can Help!

If you want to protect your driveway or parking lot and ensure it has a long lifespan, choose PTG Enterprises for your sealcoating and asphalt needs. We offer commercial concrete, masonry, asphalt installation, repair, and paving throughout Baltimore, Harford, Anne Arundel, Howard, and P.G. Counties. If you are interested in hearing how we can help you, contact us online or give us a call at (410) 636-8777. For more tips and tricks, be sure to follow us on Facebook, Twitter, YouTube, LinkedIn, Google+, and Flickr.

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