Slurry Seal Best Practices

Many pavement managers use a ⅛ inch (0.3 cm) rule-of-thumb, rather than ¼ inch (0.6 cm) rule of thumb when examining crack width in the possible application of crack seal + slurry seal.

To ensure success, the laboratory performing the mix design should be aware of your project’s application and use.

Screen the material immediately prior to loading the truck mounted paver or mobile support unit. This way, there is no possibility of contamination when re-handling the material.

Require a recalibration when material changes, conveyor seals, and/or emulsion pumps have been replaced.

Require the contractor to perform a calibration with the inspector on site, with the specific materials for the job. This step has a high potential for increasing the quality of the job.

The agency can provide early notification by website, newspapers, signs and/or door hangers. The contractor can notify by signs and/or door hangers the day before and the day of the application.

Speak with nearby agencies and local contractors to determine the normal practice in the area. Note that quality can be achieved on good asphalt surfaces either way, but the mix design must be prepared knowing if the pavement will receive a tack coat.

Ensure crack sealing material is not excessive, as it can be picked up by the slurry seal paver tires and spreader box runners.

To increase the longevity of the slurry seal, roll parking lots, cul-de-sacs, and other pavements that will not receive regular traffic.

Although slurry seal is typically placed on asphalt pavements, concrete and brick surfaces can be treated as well. This requires the application of a tack coat.

Some agencies also opt for a Cape Seal in lieu of a stand-alone Chip Seal in more heavily populated areas to provide a smoother texture finish wearing surface than the Chip Seal alone can provide.

Treat vegetation with herbicide early to prevent it from growing back following the project.

Screen the material immediately prior to loading the truck mounted paver or mobile support unit if oversize is present in the aggregate. This way, there is no possibility of contamination from re-handling the material.

Inspect the loading area daily, with special emphasis on the emulsion loading area to ensure that all areas are kept clean and orderly.

In residential areas, place a cone at the end of each driveway until the new slurry seal has cured adequately to carry traffic, and to explain the reason for these cones in the public notifications.

• Spray the surface to be hand-worked lightly with water before applying the material.
• Perform handwork first, so as to have as much area as possible applied by the spreader box.
• Tar paper can be used at the beginning and end of a pull to provide a straight edge.

• Using tar paper (roofing felt) to end the first pass will provide a straight edge and eliminate handwork.
• Pulling a spreader box until empty will cause problem in the slurry seal in the future.

Temperature, humidity and wind conditions all affect slurry seal break and cure times, and an experienced contractor will take these variables into consideration when formulating the emulsion and utilizing field additives during the course of construction.

It is recommended to use a laboratory accredited by AASHTO re:source or equivalent.