For a prime coat to be effective it must be able to penetrate into the base course. Usually a light grade of medium curing cutback such as an MC-30 will work well. However, in a lot of areas air quality is of concern and the EPA has restricted or eliminated the use of cutbacks. In such areas the use of an emulsified asphalt is necessary. There are several ways to accomplish a prime when using an emulsion:

Most emulsion manufacturers make proprietary products, ONE of which is an emulsion specifically designed for use in prime coats.

If the granular base material has a gradation that is somewhat porous, placing a prime coat can often be affected by placing a slow-setting emulsion (SS-1, SS-1 h, CSS-1, CSS-1 h) diluted 5 PARTS water to 1 part emulsion. By applying several (4 or 5) light applications (0.10 gal/sy), a waterproof surface can be obtained on the base course.

Incorporate an emulsion into the COMPACTION water while placing the last 2 to 3 inches of the base course. Use a dilution and application rate which will provide 0.1 to 0.3 gallon per square yard (3:1 dilution; 4 applications; 0.15 gal/sy rate).

Complete placement of the base course material, then scarify up about 3/4 inch. Apply about 0.20 gal/sy 2 of straight emulsion (undiluted) and blade mix it with the scarified material. Then RELAY the mixed material and compact.

For a prime coat to be effective it must be able to penetrate into the base course. Usually a light grade of medium curing cutback such as an MC-30 will work well. However, in a lot of areas air quality is of concern and the EPA has restricted or eliminated the use of cutbacks. In such areas the use of an emulsified asphalt is necessary. There are several ways to accomplish a prime when using an emulsion:

Most emulsion manufacturers make proprietary products, one of which is an emulsion specifically designed for use in prime coats.

If the granular base material has a gradation that is somewhat porous, placing a prime coat can often be affected by placing a slow-setting emulsion (SS-1, SS-1 h, CSS-1, CSS-1 h) diluted 5 parts water to 1 part emulsion. By applying several (4 or 5) light applications (0.10 gal/sy), a waterproof surface can be obtained on the base course.

Incorporate an emulsion into the compaction water while placing the last 2 to 3 inches of the base course. Use a dilution and application rate which will provide 0.1 to 0.3 gallon per square yard (3:1 dilution; 4 applications; 0.15 gal/sy rate).

Complete placement of the base course material, then scarify up about 3/4 inch. Apply about 0.20 gal/sy 2 of straight emulsion (undiluted) and blade mix it with the scarified material. Then relay the mixed material and compact.