What is it?
Fog seal is an application of a dilute emulsion without an aggregate cover.
Its purpose is to seal and enrich an under-asphalted surface or to tighten and waterproof an open texture pavement. Fog seals can also be used as pre-seals.
How is it done?
Generally a Cationic Slow Seal (CSS-1) or CSS-1h emulsion is diluted up to 50/50 with water. The CSS-1 can be diluted by either adding the water to the emulsion or the emulsion to the water. The former method usually generates more foam, depending on the drop from the fill stem and the water pressure. It is applied at .1 to .15 gallons of dilution per square yard. (Application can vary depending on pavement texture, local conditions, and traffi c.) It is desirable to keep traffi c off the fog seal until the emulsion cures (turns black). However traffi c can use it immediately but at a reduced speed to prevent skidding and/or splashing on the cars. The skid resistance of the pavement may be reduced until traffi c wears some of the asphalt from the surface.