For sand-clay and shell stabilized bases, what is the minimum application rate for a prime coat?

The minimum application rate for a prime coat on sand-clay and shell stabilized bases is established to ensure optimal bonding and performance of the asphalt layer that will be applied above it. The selected application rate of greater than or equal to 0.15 gallons per square yard is determined based on industry standards and best practices, which take into account factors such as the texture and porosity of the base material, environmental conditions, and the overall intended performance of the pavement structure.

Applying the prime coat at 0.15 gal/syd or more ensures adequate penetration into the base material, which promotes adhesion between the prime coat and the asphalt layer. Insufficient application rates can result in poor adhesion, leading to premature failure of the asphalt surface, such as cracking or raveling.

While the other rates mentioned in the options provide varying levels of coverage, the standard is firmly set at a minimum of 0.15 gal/syd to ensure that the essential characteristics of the prime coat can effectively fulfill its purpose in the paving process. This careful calibration of application rates allows for the best preparation of the base, thereby enhancing the longevity and performance of the complete pavement system.