The type of preservation treatment applied is dependent on many factors including roadway condition, location, and age. The Pavement Condition Index, or PCI, assigns a rating to each roadway based on those factors. PCIs range from 0 to 100, with higher PCI values indicative of better pavement conditions.

 

Full-Depth Reclamation is an in-place recycling method for reconstruction of existing pavement, by pulverizing the existing asphalt and portion of underlying base and using them together as the new base for the new pavement section. This process includes adding cement, foam asphalt, or other chemicals to this new base layer, therefore increasing its strength capacity.  A surface lift of asphalt is added to completes the FDR treatment. This process provides a stronger foundation for present and future traffic. This process produces a cost-effective solution that maximizes limited budgets.

 

HMA consists of mineral aggregate bound together with asphalt, laid in layers, and compacted. This treatment is regarded by most road departments as a standard for road maintenance and restoration, and has been for several decades. It produces durable, long-lasting results, and can increase pavement life by 15 years or more. Combined with other processes, such as milling or grinding of old pavement, an AC overlay can transform a tattered road surface into a like-new condition.

 

A slurry seal is the application of a mixture of water, asphalt emulsion, aggregate (very small crushed rock), and additives to an existing asphalt pavement surface. This combined mixture of the emulsion and aggregates represents “slurry.” Polymer is commonly added to the asphalt emulsion to provide better mixture properties. The placement of this mixture on existing pavement is the “seal” as it is intended to seal the pavement surface and extend its life until future reconstruction can occur.

Roadways chosen for cyclical slurry seal applications would typically be treated every five to seven years.

 

A fog seal is a light application of a diluted slow-setting asphalt emulsion to the surface of an aged pavement surface. Fog seals are low-cost and are used to restore flexibility to an existing asphalt pavement surface.

 

A Chip Seal is liquid asphalt is sprayed onto the pavement followed immediately by spreading on a thin layer of uniformly sized aggregate chips. The new surface is then rolled to embed the chips in the asphalt. Once the asphalt has cured (usually taking about 24 hours or less) any loose chips are swept up.

 

Microsurfacing is similar to slurry seal. It consists of the application of a mixture of water, asphalt emulsion, aggregate (very small crushed rock), and chemical additives to an existing asphalt concrete pavement surface. Polymer is commonly added to the asphalt emulsion to provide better mixture properties. The major difference between slurry seal and microsurfacing is in how they “break” or harden. Slurry relies on evaporation of the water in the asphalt emulsion. The asphalt emulsion used in microsurfacing contains chemical additives which allow it to break without relying on the sun or heat for evaporation to occur. Thus, microsurfacing is an application that hardens quicker than slurry seals and can be used when conditions would not allow slurry seal to be successfully placed.

While microsurfacing is a better product than slurry sealing with relatively same costs, it requires ADA upgrades (curb ramps and slip resistant warning surfaces) and can significantly impact a project’s budget, leaving slurry seals a more commonly used treatment option.

 

A cape seal is a combination of treatments, it is a chip seal followed by a slurry seal or a micro seal.

 

Dig Out Repairs - Completing small asphalt or concrete patch repairs.

 

Crack Seals - Filling cracks in the roadway with hot sealant to protect the pavement from water, which can enter the cracks and further damage the road.