Asphalt is a material that is perfect for paving because of its high level of durability. It can last two decades or even longer if properly cared for. However, if it isn’t protected, it will be vulnerable to damage by use and the elements. The sun’s UV rays and water from the environment can wear on asphalt and cause it to oxidize on the surface. This oxidation can make the asphalt more vulnerable to developing structural problems. You may need a slurry seal or a seal coat to protect your paved surface. There are a lot of differences between a slurry seal and a seal coat, and you may need one more than the other.
What Is a Slurry Seal?
A slurry seal is much like a seal coat, but there are some technical differences between a slurry seal vs seal coat. The composition of a slurry seal is different from a seal coat. Slurry seals have an extra ingredient in them, and that is aggregate. The elements both types of seals have in common are asphalt emulsion and various additives. Seal coats may also contain mineral fillers. A slurry coat is a thick cold treatment often used on paved areas to fix certain problems and prevent others.
When asphalt gets older, the binder in it will get weaker. When this happens, the binder allows chunks of aggregate to disappear from the surface. A seal coat can’t replace the lost aggregate, which can mean that the surface develops small depressions that can then take on water. As water pools in those depressions, it can cause a lot of damage to the asphalt.
With the aggregate-containing composition of a slurry seal, the gaps and cracks in the surface can be filled in and prevent further damage from those small depressions. With a slurry seal, the surface of the asphalt is made smoother, making it easier to walk on and drive on. It can help to prevent tripping accidents on the property by filling in those gaps.
Slurry Seal Application and Uses
There are three types of slurry seals that are classified based on their aggregate size that is in them. Various slurry seal types are used for different paving projects based on the use of the asphalt and the amount of damage to it. Slurry seal with a smaller aggregate size is often used for parking lots and other areas that don’t get much traffic.
The type with medium-sized aggregate particles is often used for roads because frequent use often damages them. The larger size is often used for asphalt that has a lot of damage and needs a lot of divots and pond areas filled in from lost aggregate.
Every type of slurry seal requires about eight to 10 hours to cure fully. The exact time will depend on the specific mixture and how it was applied. Slurry seal has a rough texture that is good for safety and can last for up to eight to 10 years once applied.
However, it generally costs more than getting a seal coat. It requires using specialized equipment that will mix the compound and a specialized applicator that is a part of the mixer. Slurry seal is thicker than a seal coat, and the ingredients are brought to the site and then cold mixed and applied. Once it has been applied, it is a layer that is highly similar to the asphalt under it.
What Is a Seal Coat?
A seal coat is also used to treat asphalt, but it has a different texture and uses. A seal coat is made to rejuvenate the surface of the asphalt. Asphalt that gets older can oxidize and lose its water resistance, which can lead to a lot of damage to the surface. When a seal coat is applied to the asphalt, it adds more protection to the asphalt to prevent further damage.
This coat will make the asphalt more resistant to water by making the top layer more waterproof and harder for water to get through to the lower layers of the asphalt. It also protects the asphalt paving from UV exposure and the oxidation it can cause. A seal coat will also make the pavement more resistant to damaging chemicals like oil. In addition, it adds a darker, more lustrous look.
A seal coat can be made from an asphalt emulsion or coal tar. Better results are often achieved using a seal coat made from coal tar because they are generally more consistent. The seal coats made with asphalt emulsion can vary significantly between manufacturers and batches. However, the asphalt emulsion varieties are less expensive and more commonly used because of their cost and availability. Some manufacturers are now making seal coats made from both of these ingredients.
Seal Coat Application and Uses
Seal coats are thinner protectants than a slurry seal. A seal coat uses water to dilute the consistency and is applied to the asphalt with sprayers. Seal coats use a lot of secondary additives such as polymers and mineral fillers that make the coating more consistent and tougher and increase the resistance to chemicals and UV rays. Before it can be applied, though, the asphalt has to be thoroughly cleaned to get rid of debris and oil so that the seal coat can bind to the asphalt below it.
Curing can take longer than a slurry coat, but the exact curing time will depend greatly on the weather, humidity, and temperature. It may take as little as two to four hours to cure or as long as two days. It’s best to apply it during times of year that are drier and warmer for this reason. Seal coats don’t last as long as slurry seals, so they should be applied every two years.
Whether a slurry seal vs seal coat is used depends a lot on the condition of the asphalt, its location, and how much traffic it gets. Both techniques are helpful to asphalt and can make it last longer, resist damage, and look better.