Asphalt Seal Coating & Asphalt Maintenance

Questions & Answers

What is Seal coat?

Seal coats serve to seal the top of the asphalt, preventing water from penetrating the surface of the pavement and protecting the top layer of asphalt from oxidation and wear caused by exposure to the sun and air. Seal coats also beautify the pavement by providing a smooth, black, even surface ideal for painting and sweeping. Seal coats are designed for off highway use where there are low traffic speeds and tight turning radiuses such as parking lots, mobile home parks, schools, churches, driveways and road shoulders.

How Does Sealcoating Help?

Seal coating seals the asphalt pavement, preventing the oxidation and erosion of the top layer of asphalt. On older pavements seal coating replaces the fine particles lost from the asphalt surface due to oxidation. Seal coating also seals the small cracks that can turn into large cracks and prevents water from seeping down to the base material. Seal coating helps protect the asphalt from the sun as well as the harmful effects of chemical spills such as oil and gasoline.

What causes asphalt pavement to fail?

Assuming that the initial asphalt pavement was designed and constructed properly, the primary cause of failure is the penetration of water into the asphalt base. This process begins with the oxidation of the pavement surface which causes the asphalt to dry and become brittle. This leads to the erosion of the top layer of fine particles and the appearance of larger stones and small cracks on the surface.

If left untreated, these cracks expand and eventually allow water to penetrate through to the base of the pavement. When this occurs, the base material moves and settles, leading to an “alligator hide” appearance. When the pavement reaches this stage, the only option is removal and replacement of the old asphalt.

When should seal coating be done?

Generally you should wait a few months before sealing new pavement to allow it time to cure. After a surface has been sealed it should be resealed every 3-4 years or as necessity dictates.

What are seal coats?

Seal coats generally consist of a mixture of emulsified asphalt, water, mineral fillers and various other admixtures. They are applied directly to the surface of an asphalt pavement with a rubber squeegee, broom or mechanical spray.