Sealcoating Materials

Asphalt Sealcoating Materials Explained

There are several types of asphalt sealcoating materials that contractors can apply to asphalt. These materials include Coal Tar Emulsion, Asphalt Emulsion, and Oil Based sealers. This article will cover the different types and the benefits of each.

Coal Tar Emulsion

The first asphalt sealcoating material that will be discussed is Coal Tar Emulsion. This material is created as a result from the “coking process” in steel manufacturing. It is comprised of a mixture of thousands of chemicals that are different in molecular structure than asphalt itself. This allows Coal Tar Emulsion to protect the asphalt from the harsh effects of UV rays, petroleum based products and water.

Coal Tar Emulsion is the most durable sealer on the market. The natural life span of an asphalt sealcoating job performed with Coal Tar Emulsion is approximately 5 years. This time estimate depends on the traffic volume that the asphalt experiences on a daily basis. In comparison, the other sealers typically last 2-3 years maximum for the same traffic volume. Currently, Coal Tar Emulsion is the sealer of choice for the vast majority of Federal Airport sealcoating projects, due to its ability to protect againt the ill effects of Jet Fuel.

The other asphalt sealers are petroleum based in chemical structure and the Coal Tar Emulsion is not. This is the biggest advantage that Coal Tar Emulsion has over the other sealers. When gasoline and oil disperse over the asphalt pavement, it has a natural tendency to bond with the asphalt due to the similarities in chemical structure. This bonding process deterioration in the asphalt leads to raveling, which is when the stones start to separate from the asphalt.

Coal Tar Emulsions’ down side is its odor and blueish/blackish gray color. Many contractors will mix the darker Asphalt Emulsion with the Coal Tar Emulsion sealer to create a darker sealer and get the best of both worlds, superior durability and dark color. Contractors tend to use their own mix rates. General mixing guidelines are 60-90% Coal Tar Emulsion to 10-40% Asphalt Emulsion.

Coal Tar Emulsion is a water based sealer. Water is used to enable the contractor to use it in a workable state. After the sealer has been applied, the water evaporates, which leaves a durable film. Many people have a tendency to ask if an Coal Tar sealer is latex or oil based. The answer is neither. Instead its main composition is Coal Tar itself.

Asphalt Emulsion

The next sealcoating material is Asphalt Emulsion. This material is fairly new to the asphalt sealcoating world. It was created because the supplies of Coal Tar Emulsion have been diminishing in recent years.

Asphalt Emulsion is an asphalt sealer that is derived from asphalt itself. The main benefit of an Asphalt Emulsion based sealer is the dark black color. Asphalt Emulsion restores the original color to the asphalt. As previously mentioned, Asphalt Emulsion is blended with Coal Tar Emulsion to take advantage of the color and durability of both asphalt sealers. Contractors have the ability to determine the percentage of each sealer used in the mix design.

Asphalt Emulsion’s biggest down fall is the fact that it does not hold up well against the effects of  petroleum products such as gasoline and oil. Although there are some decisive limitations in Asphalt Emulsion sealers, there have been great strides in correcting the composition and effectiveness of Asphalt Emulsion sealers in recent years. 

Polymer Modified MasterSeal (PMM) is a high performance mineral reinforced asphalt emulsion sealcoat blended with polymers and special surfactants for superior adhesion, flexibility, and durability with a deep black color.

Oil Based Asphalt Sealer

The last asphalt sealcoat material that will be discussed is the oil based asphalt sealer. This sealer is primarily used by asphalt paving contractors because it is located at the asphalt plants. Not many professional sealcoating companies use this type of sealer due to the inherent limitations.

An oil based asphalt sealer, also known as “asphalt rejuvenator”, is comprised of asphaltic chemicals based with an oil composition. This asphalt sealing material has the same limitations as Asphalt Emulsion sealer. Because it is a  petroleum based product, it does not protect against petroleum products. Also, this material has a distinct odor that last for days. Another limitation to oil based sealers is that it takes a week to cure properly before line painting can be accomplished. Commercial property owners considering oil based sealer must take this into account.

Conclusion

A property owner or manager must take into account the pro’s and con’s of each asphalt sealer when selecting a asphalt maintenance contractor. Every contractor uses different material and mix design. No matter what asphalt sealing material is used, always make sure that the contractor is using sand in the material. The sand helps to restore traction to the surface that is lost from the sealcoating process.