The Department of Transportation and Mobility uses a variety of asphalt treatments for street repair as well as preventative pavement maintenance, which helps preserve the condition of the roadway and extend the life of the asphalt.
There are several treatment types, or combination of treatment types, that can be applied depending on the roadway condition, traffic volume and available funding.
Fog Seal
A thin layer of asphalt emulsion, applied to the street surface, that helps cover small roadway imperfections, cracks or other small voids and seals existing asphalt to preserve and rejuvenate the asphalt.
Slurry Seal
A mixture of water, asphalt emulsion, aggregate (very small crushed rock), and additives applied to an existing pavement surface. A slurry seal is similar to a fog seal with the exception of the aggregate added to the mixture. This treatment is used to seal the pavement surface and extend the life of the asphalt.
Micro Surface
A thin layer of asphalt emulsion applied to the pavement surface and mixed with aggregate. Vehicles can usually begin driving on the road a few hours following the application of a micro surface treatment. The micro surface can remain flexible and may be subject to temporary markings caused by sudden turning movements. Over time, seasonal weather and traffic will smooth out these pavement impressions.
Cool Pavement
A top surface treatment to help preserve and extend the life of the asphalt. Cool pavement is a Titanium Dioxide (TiO2) based emulsion that is solar-reflective designed to reduce roadway temperature and neutralize vehicle emissions. The treatment application absorbs within minutes and does not change the appearance of the roadway.
Chip Seal
Asphalt emulsion applied to the pavement surface, then covered with aggregate ("chips") to seal the roadway surface. The chip seal may require several days to cure. After the curing process, any excess aggregate chips will be swept from the roadway. A micro surface treatment may be applied on top of the chip seal to cover the aggregate chips.
Mill and Pave
The top layer of asphalt is removed (milled) and repaved with new asphalt.
Reconstruction
All existing asphalt and subgrade is removed, replaced with new subgrade to strengthen the base, and repaved with new asphalt. This is the most extensive and expensive treatment type.
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