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.
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.
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.
The International Slurry Surfacing Association provides detailed advice on the design and application of slurry surfacings. Their web address is http://www.slurry.org/
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Asphalt Emulsion Manufacturers Association