Micro Surfacing 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 and micro surfacing.

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

In residential areas, place a cone at the end of each driveway until the new micro surfacing 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.

• A variable width spreader box eliminates the need for half passes.
• Using tar paper (roofing felt) to end the first pass eliminates handwork.
• Pulling a spreader box until empty will cause problems in the micro surfacing in the future.

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

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

Do not specify an application rate for rut filling or a leveling course, as it is impractical to measure the ruts and low spots to know how much material will be required.  Rut filling is typically paid by the ton.

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 micro surfacing paver tires and spreader box runners.

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

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

Screen the material immediately prior to loading the nurse truck/mobile support unit. This way, there is no possibility of contamination when 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.

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