Public Works -Road Funding Programs

What Are Slurry Seals? Why Use Them?

A Slurry Seal is:

A road wearing surface treatment that seals, protects and can restore asphalt pavement

A mixture of small, graded aggregates (sand and rock), asphalt emulsion, cement and other additives, usually including polymers

Applied using a special combined pugmill (mixer) and spreader/paver unit that is mounted on a truck or self-propelled

Why Use A Slurry Seal?

A Slurry Seal extends pavement life at a low cost by:

ü Sealing asphalt pavements to protect them from oxidation much like paint is used to seal and protect wood.

Sealing minor cracks and improves traffic safety by:

Restoring surface texture and skid resistance
Correcting raveling

Isn’t A Slurry Seal just another kind of overlay? No. A slurry seal is a surface treatment that looks much like an asphalt concrete overlay, but is very different in some key aspects:

Slurry seals generally cost about ten times (10x) less than the simplest, structural asphalt concrete overlays and can be in the range of twenty times (20x) less than more involved rehabilitative overlays when all costs are accounted.

An overlay adds significant thickness and strength to the pavement to reduce the amount of flexing of the pavement under traffic loads. A slurry seal coats, seals, and in some cases even restores the surface of the existing asphalt pavement to protect the existing strength in the pavement, but does not add any strength.

Slurry can be placed more quickly, but may take several hours to “set” or “break” before traffic can be allowed to use it. Overlays and the associated work can take significantly longer, but are generally ready to take traffic within an hour of placement.

Slurry is placed at ambient “cold” temperatures, while overlays are placed hot (generally 260ºF-300ºF) and can burn people or pets that walk on or touch the fresh, hot surface.