Nothing is capable of extending the lifespan of asphalt pavement quite as well as sealcoat. But when it comes time to select the ideal sealcoat for their project, many people struggle to understand the differences between the different varieties available. If you would like to increase your knowledge about the range of sealcoats, read on. This article will distinguish between two of the most common types available today.
Sealcoat: An Introduction
Many people are surprised to learn that the main ingredient in sealcoat is actually asphalt--specifically, a mixture of asphalt and water known as asphalt emulsion. To make this mixture more stable, substances known as surface-active agents are often added. Likewise, a range of binding agents are used in sealcoat. These may include:
When sealcoat is introduced to pavement, it undergoes a process often referred to as "breaking." This simply means that the asphalt and the water separate. The water evaporates, whereas the asphalt is absorbed into the pavement, thereby adding an extra layer of protection.
Perhaps the most basic form of sealcoat, fog seal is composed of a simple asphalt emulsion. This mixture is diluted to a very thin consistency so that it can be spread over the surface without resulting in a slippery layer on top. Fog seal is best suited for the following applications:
- as a means of delaying aging
- increasing flexibility
- providing a waterproof barrier
Fog seal is most commonly applied to surfaces composed of coarse aggregate. Because such surfaces contain relatively larger chunks of gravel, the fog seal is able to pool up in between them. Smooth surfaces made up of smaller aggregate, on the other hand, are not as well suited to fog seal. This is because the fog seal will remain on the surface, thereby reducing traction.
The primary distinction between sand seal and fog seal has to do, not with the sealcoat itself, but with the post-application process. With sand seal, once the asphalt emulsion has been spread across the pavement, a covering of sand is placed on top. This layer of sand is then rolled smooth.
Sand seal has numerous benefits. To begin with, it can help to fill in problematic cracks that may be forming on the pavement's surface. The sand also acts to increase traction and skid resistance. Thus, while fog seal is perfectly appropriate for a residential driveway, sand seal is by far the better option when sealcoating a high-traffic road.
For more information, seek out services such as paving by Pavement Solutions Inc.