Slurry Seal Emulsions

Introduction to Slurry Seal

History

In the early 1930's, a coating consisting of a mixture of very fine aggregates, asphalt binder and water was laid out on a road in Germany. It proved to be a novel approach, a new and promising technique in maintaining road surfaces -- and marked the beginning of slurry seal development.

Later in that decade, extensive worldwide experimentation began in earnest. But it was not until the 1960's, with the introduction of improved emulsifiers and continuous flow machines, that real interest was shown in the usage of slurry seal for a wide variety of applications.

Continuing advancements in mixing methods, emulsions and machinery have made slurry seal today's choice in providing highly durable, low cost paving and surface maintenance. As a treatment for everything from residential driveways to public roads, highways, airport runways, parking lots and a multitude of other paved surfaces, slurry seal is now used extensively throughout the world. Local, state and federal agencies -- including the military -- have a growing and ongoing commitment to the use of slurry seal in their maintenance programs, attesting to its effectiveness and economy.

What is Slurry?

The principal materials used to create slurry seal are aggregate, asphalt emulsion and fillers, which are mixed together according to a laboratory's design mix formula. Water is also added for workability.

Asphalt emulsions serve as a binder, holding the crushed aggregate together and adhering the new slurry surfacing to the old surface over which it is being applied. Various emulsions and aggregates are used to meet the conditions, specifications and requirements of individual projects.

The aggregate must be clean, crushed, durable, properly graded and uniform. The asphalt emulsion is a three-part system consisting of asphalt, water and emulsifier. Fillers such as portland cement, hydrated lime or aluminum sulfate liquid are often used in small quantities as stablilizers or chemical modifiers.

How is Slurry made?

Slurry is made in specially designed equipment, either truck-mounted or self-propelled. This equipment carries a quantity of unmixed materials which are blended together in a continuous flow pugmill. The use of this technologically advanced machinery insures a smooth, consistently uniform mixture.

Slurry is made quickly and accurately at the project site. Mixing and spreading are accomplished in one continuous operation, with the surface being re-opened to travel within a few hours.