Most typically utilized in traditional road design, prime coat bonds loose material particles on the surface of the base before applying a following layer of asphalt. In doing so, the fine particles in the base are critical to developing the structural integrity of the entire cross section and eliminate costly base repairs due to moisture.
Prime coat can also be used in waterproofing the base during construction. This allows increased traffic flow and minimal delays to taxpayers.
Prime coat penetrates the surface of a base 1-2 centimeters deep, plugging capillary voids from the surface and preventing water from entering the base layer. In bases with fine particles, prime coat serves as a strengthening barrier to effectively prevent base failure caused by moisture.