People outside the paving industry know little about the materials and processes available for installing, maintaining, and repairing pavement. Fortunately, our experts do and are always excited to share their knowledge with consumers to keep them educated and up to date on the world of asphalt paving. Today, we want to share some information on a little-known asphalt maintenance and improvement process: fog seals.
A fog seal applies a thin, specially formulated liquid asphalt emulsion to an existing asphalt pavement structure, like a residential street or highway. The process gets its name because of the application process, which involves spraying the emulsion mixture onto the asphalt surface in a process called 'fogging.'
The emulsion used for fog seal applications contains an emulsifying agent (surfactant), water, globules of paving asphalt, and occasionally a rejuvenator. For a deeper understanding, a surfactant you are familiar with is soap. When used for washing dishes or clothing, a surfactant will help remove dirt by suspending dirt particles in the water used for washing. Similarly, in an asphalt emulsion, the surfactant suspends the asphalt paving globules until the application, when the emulsion's water will begin evaporating. In addition, the rejuvenator is an asphalt additive that will help soften the existing pavement slightly when the fog seal is applied to promote improved bonding between the paving and the sealer.
As asphalt paving ages and is subjected to heavy traffic, it oxidizes, causing cracks to develop on the surface that can partly be attributed to the paving becoming brittle. Oxidation is one of the primary reasons that asphalt paving fades from the rich ebony color present when an asphalt surface is initially installed or resurfaced. Fog seal applications are designed to seal narrow cracking, restore slight flexibility to the paved surface, provide the rich, deep ebony-colored pavement surface, and help preserve the pavement's structural integrity.
This maintenance and improvement process is usually added to existing asphalt pavement on a cyclical or intermittent basis. Pavement conditions, traffic loads, weather, and location are the factors used to determine whether a fog seal application is appropriate for a specific paved surface. Roadways approved for fog seal treatments commonly have minor cracks and color fading. However, they are in a condition where the fog seal will help extend the pavement's life until resurfacing is necessary. For optimal protection, roadways chosen for intermittent fog seal applications are usually treated every three to five years. In addition, fog seal applications are often applied to new pavement in desert areas to retain flexibility and protect it from oxidation.
Fog seals in Gainesville, Texas, are applied with a distributor truck that heats the emulsion slightly before spraying it onto the pavement surface. The application leaves the paved surface with the appearance of being spray painted black.
We are glad to share some of our industry knowledge to keep you up to date on asphalt processes and materials. Please call us if you need asphalt installation, maintenance, or repairs. We want to be your paving contractor.