Understanding Asphalt Sealcoat

In order to get the longest possible lifespan from an asphalt surface, it is necessary to apply sealcoat on a periodic basis. Of course, not all sealcoats will offer the same benefits. If you would like to learn more about the kinds of sealcoat currently on the market from paving services, read on. This article will discuss two of the most widely used types.

The Basics

First, it will help to understand a bit about the makeup of sealcoat in general. All sealcoats contain the same key ingredient, which is known as asphalt emulsion. This simply designates a diluted solution of asphalt and water. In order to boost the stability of this mixture, surface-active agents are sometimes added. Likewise, a given sealcoat may incorporate other modifiers and/or binding agents like latex, chemical polymers, and rejuvenators.

The diluted quality of a sealcoat means that it can easily be sprayed onto an asphalt surface. Once in place, the water and asphalt undergo a splitting process commonly referred to as breaking. The water molecules are then able to begin evaporating, allowing the asphalt portion of the sealcoat to bond with the pavement. This acts to refresh those aspects of the asphalt that have been lost to wear and degradation.

Fog Seal

This is perhaps the most basic of all forms of sealcoat. It contains very little aside from the diluted asphalt emulsion discussed above. This dilution is thinned to a consistency that allows it to be easily applied and spread across the pavement, while avoiding the pitfall of excessive thickness, which would result in a slippery finish.

The purpose of fog seal is to protect the asphalt against premature aging. Likewise, it acts to boost the flexibility of the pavement, while also adding a waterproof element to the surface. This helps to protect the asphalt deeper down from water--one of its most significant enemies.

Fog seal is at its most effective when being used to sealcoat coarse asphalt pavement--in other words, asphalt pavement constructed using a relatively large spectrum of crushed stone aggregate. The larger size of the aggregate allows the fog seal to puddle up, thus giving it the time it needs to thoroughly soak into the surface. Smooth asphalt surfaces, on the other hand, tend to see fog seal evaporate before it has effectively penetrated.

Sand Seal

Sand seal represents a variation of fog seal in which the application of sealcoat is followed up by a fine layer of sand. This sand is then rolled into the asphalt, where it acts to fill in small cracks or potholes, while also increasing the traction provided by the pavement. This makes sand seal a popular choice for use on roadways--especially those located in precipitation prone parts of the country.