Drainage: The Key To A Quality Asphalt Road

When it comes to the quality and longevity of any asphalt road, proper drainage is essential. Water has the potential to cause permanent damage to the structure of the road itself. Engineers and construction crews must be vigilant in establishing proper drainage throughout the planning and construction phases. Moisture management will ensure that any asphalt road is built to last.

Surface Drainage

The first type of drainage that must be considered when constructing an asphalt road is surface drainage. Water from rain or melting snow will come into contact with the surface of your road. If proper surface drainage doesn't exist, this water will remain on the surface of the asphalt until it evaporates.

Standing water can reduce safety by making it difficult for a vehicle's tires to grip the road surface. If freezing temperatures exist, standing water can turn into dangerous black ice.

Eliminating standing water requires adequate surface drainage. This can be achieved by creating a slightly convex profile to the road during construction. The convex curvature encourages any moisture on the surface of the road to drain off to the shoulders, thus eliminating standing water from your road in the future.


Asphalt is a permeable material. This means that some of the water that finds its way onto the surface of your road will seep through the asphalt and into the base materials below. Water accumulation within the base materials can result in the formation of weak spots where the asphalt can collapse.

Improper subdrainage is often evident when a road begins to develop cracks or potholes. Drainage structures must be included in the design of your asphalt road to help manage subdrainage.

A layer of packed rock should lie below the asphalt to act as a drainage filter. This rock layer will prevent the potential contamination of water moving through your asphalt road. Drainage pipes can then carry any water filtering through your road to a safe discharge site.

Managing water is a critical part of any successful road design. Proper drainage will ensure not only the structural stability of the road over time, but it will increase the safety of the road's surface as well.

Be sure that you are taking the time to consider how surface drainage and subdrainage will play a role in the design of your asphalt road. Eliminating water from the surface of the road and managing water that seeps through the pavement will ensure your asphalt road remains intact over time. Contact a company, like Lien Transportation Co, for more help.