Water Drainage for Asphalt Pavements

Why Water Drainage is So Important for Asphalt Pavements

No matter what kind of asphalt paving you’re installing, proper drainage is key to keeping it looking its best and ensuring it lasts as long as possible. In fact, it’s safe to say that proper drainage is the most important factor in asphalt longevity. Here are our top five reasons why water drainage is so important for asphalt pavements.

Prevents Surface Wear and Tear

Despite seeming relatively harmless, water is actually one of asphalt’s worst enemies. With asphalt being a crude-oil product, water and asphalt simply don’t mix, just as oil and water don’t mix. Puddles will quickly form on asphalt pavements lacking proper drainage, which is why most professional asphalt contractors will grade any surface they pave to allow for proper drainage.

In addition to grading an asphalt pavement to improve drainage, routine maintenance is essential for protecting asphalt from water damage. Regular maintenance like crack sealing, patching, and asphalt seal coating will prevent water from seeping through the porous asphalt and causing potholes and other structural damage.

Avoids Potholes and Structural Damage

When it pools on the asphalt surface, water gradually breaks the bonds between the asphalt binder and slowly seeps into the layers under the asphalt, like the aggregate base and subbase. Over time, this water saturates the supporting materials until they eventually give way under load and potholes form.

These potholes, in turn, expose more of the bottom layers to the elements and make them further susceptible to water damage – leading to significant structural damage if left unchecked. So, it stands to reason that you would want to avoid water pooling on top of asphalt for extended periods, and the only way to avoid this is through proper drainage.

Drainage Prevents Freeze-Thaw Damage

Another reason why water drainage is so important for asphalt pavements is because water expands when freezing. What this means is that any water that seeps through the porous asphalt will expand once frozen, heaving the asphalt upward and causing cracks from the bottom up. Come spring, this frozen water will begin to melt and the cracks left behind become more evident, eventually turning into potholes and causing potential major issues down the line.

Protects the Layers Below the Asphalt

As we saw above, water can often find its way under an asphalt pavement’s surface, regardless of grading and surface drains. One of the main reasons for major water damage in asphalt pavements is poor subsurface drainage. This can be achieved in a number of ways, including by using a non-porous subgrade, installing drain tiles below the surface connected to a catch basin or storm pipe, and crowning the surface to direct water toward gutter systems at the sides.

Ideally, water would flow directly into a drain or gutter, but the important thing here is to get water off the pavement as quickly as possible regardless of the method used.  

Protects More than Just the Pavement

Proper asphalt pavement drainage directs water not only away from the pavement, but also from any surrounding buildings and structures. Water seeping through the asphalt pavement and eroding the subgrade beneath could potentially expose nearby foundations to water damage over time. However, proper asphalt pavement drainage prevents excessive water from accumulating around foundations and thus helps maintain their integrity.  

Asphalt Paving Services You Can Trust

Trusted for generations, Holloway Paving has been serving Calgary and the surrounding areas for over two decades. Renowned for our commitment to excellence, we take pride in offering asphalt paving services you can rely on, backed by the high standards set by our name and history. Reach out to us today at 403-975-3030 or contact us online for a free quote on any of our services.

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