“Don’t Use Coal Tar on Asphalt Pavement,” Respected Asphalt Institute Recommends

The respected Asphalt Institute, which provides research and technical assistance to pavement managers and designer engineers primarily in the US, recommends against using coal tar sealants over asphalt.

This isn’t the first technical paving source to recommend against the use of coal tar sealants for non-environmental reasons. A European study showed that coal tar sealants are prone to shrinkage cracking and accelerated pavement degradation.

Interesting since the coal tar sealant industry often says “without coal tar sealants, pavements will degrade and fall apart.” Now the engineers and scientists who design these pavements say that asphalt pavements will do just fine without the application of coal tar sealant.

Here’s what the website says:

How should driveways and parking lots be sealed?


A light application of a slow-setting asphalt emulsion diluted with water should be applied. In most cases, a dilution of one part emulsion to one part water is used. SS-1, SS-1h, CSS-1, or CSS-1h asphalt emulsions are typically used. Commercial sealers are also available. Those containing coal-tar compounds are not recommended. The diluted material is sprayed or squeegeed onto the surface in a thin, uniform coating. The total quantity of diluted sealant normally applied is 0.1 to 0.15 gallons per square yard. Exact quantities should be based on the surface texture, dryness, and degree of cracking or raveling.