You may not realize it, but when it comes to asphalt maintenance, there is a difference between "slurry" and "sealcoating." While both slurry and sealcoating are preventative maintenance tasks that extend the life of your asphalt, there are key differences that you should be aware of. We'll outline those differences below:
1) What is the difference between a slurry and a sealcoat?
The main difference between a slurry and a sealcoat is that a slurry is thicker than a sealcoat. A slurry uses larger aggregates in its mix while sealcoats contain smaller, or in some cases; no aggreagates, in its mix.
2) When should you use slurry? When should you use a sealcoat?
While both slurry and a sealcoat protect your asphalt, they are best used in different situations.
A slurry is best for heavier traveled roadways and streets where vehicles travel at higher speeds. Since slurry uses larger aggregates, it provides a tougher surface that can withstand heavier and more constant traffic loads.
A sealcoat is best used in low traffic, low speed areas, such as parking lots and driveways. You'll generally have smaller, lighter vehicles traveling/parking on the asphalt.
3) How long does slurry last? How long does a sealcoat last?
The longevity of a slurry seal and sealcoat depends on traffic loading and weather. In general terms, you should reapply slurry every 6-9 years. You should reapply a sealcoat every 3-6 years.
4) How long does a slurry take to cure? How long does a sealcoat take to cure?
A slurry will take longer to cure than a sealcoat. In ideal conditions, a slurry will take 8-10 hours to cure while a sealcoat will take 2-4 hours to cure.
5) Which costs more, a slurry seal or a sealcoat?
A slurry seal is about twice as costly as a sealcoat. One reason why slurry is more expensive than a sealcoat is that the slurry is mixed on site and spread in a large machine. On the other hand, a sealcoat can be applied using a spray or squeegee.
6) Which makes your asphalt look "nicer," a slurry or sealcoat?
This can go either way. Both give your asphalt a rich, black color, as if the asphalt were brand new.
But a sealcoat provides a smoother surface than a slurry because it contains smaller (or has no) aggregates. If your pavement has unraveled and is rough, then a slurry may help in filling in surface voids (because it contains larger aggregates) and correct rough spots on the pavement.
However, if your pavement is bad and has structural damage, neither a slurry nor a sealcoat will help resolve the issue. Both would only provide a superficial, cosmetic "fix," in terms of appearance.
Should I use a slurry, or sealcoat, for asphalt maintenance?
For most property managers and home owners, the most cost-effective way to extend the life of your asphalt is to sealcoat (instead of slurry). A slurry would be "overkill" for a parking lot if the parking lot is in good condition and structurally sound.
But the most important step is having your pavement inspected by an expert. An expert will help you determine the best course of action to extend the life of your pavement.
Cole is the Manager of GP Maintenance Solutions. He’s been involved in the asphalt paving/maintenance industry since 2006 and has experience in both estimating and project management for City, State, Federal, and Private projects. Connect with Cole on LinkedIn.