Basics of Slurry Surfacing With Asphalt Emulsions

What is slurry surfacing?

Slurry surfacing is a thin dense-graded cold mixed overlay. Slurry seals are thin layers rich in asphalt used for residential streets, airports and in some countries for sidewalks and parking lots. Microsurfacing is a premium product based on specially selected aggregates and polymer modified asphalt emulsion. Microsurfacing is designed to be applied in thicker lifts for high trafficked areas.

How is a slurry seal or microsurfacing applied?

Normally, aggregate, emulsion, water and filler such as cement are mixed in a mobile mix paver and the mixture which has a slurry like consistency is allowed to fall into a ‘spreader box’ which distributes it over the road surface to a predetermined thickness. Slurry surfacings may also be hand applied. The slurry cures rapidly (typically within 1 or 2 hours) and traffic can be allowed on it.

What type of asphalt emulsion is suitable?

Cationic slow-setting emulsions are used. They are selected on the basis of a laboratory mix design process, which involves tests on the compatibility of the aggregate and the emulsion, and on the durability of the cured seals.

Where can I go for further information?

The International Slurry Surfacing Association provides detailed advice on the design and application of slurry surfacings. Their web address is

Where else can I learn more about slurry surfacings using asphalt emulsions?

You can order AEMA’s Basic Asphalt Emulsion CD-Rom right here on this web site – just click here.

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Asphalt Emulsion Manufacturers Association
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Glen Ellyn, IL 60137

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