Cold asphalts for slurry surfacing

Cold asphalts for slurry surfacing are commonly used worldwide for surface maintenance, for surface maintenance prevention and, above all, for the restoration of surface skid resistance of highways, city streets and airport pavements. 

Slurry surfacing is surface treatment consisting of a mixture of aggregates, bituminous emulsion, water and additives, which are mixed and laid in-place. A slurry surfacing product may consist of one or more layers. 

The slurry surfacing in which the bituminous emulsion is polymer modified is known as micro-surfacing. Micro-surfacing is normally made with larger-sized aggregates and is considered as high-performance surfacing material. 

When slurry surfacing is made of small-sized aggregates and the bituminous emulsion is not modified, it is called slurry seal. 

The thickness of the single layer of slurry surfacing ranges from 4 to 12 mm. The cold asphalt mixture for slurry surfacing is produced and laid in situ with a purposely built travel plant. 

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Cold asphalts for slurry surfacing are specified by international standards, specifications and guidelines, such as CEN EN 12273 (2008) for slurry surfacing, ASTM D 3910 (2011) or International Slurry Seal Association (ISSA) A105 (2010) for slurry seals and ASTM D 6372 (2010) or ISSA A143 (2010) for micro-surfacing. 

Materials used for the production of cold asphalts for slurry surfacing are bituminous emulsion, graded aggregates (medium and fine size), water and additives. The additives may be mineral filler, added to the aggregate mix, or chemicals, diluted to water, to improve mixture consistency and to adjust mixture breaking and curing properties. 

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