Treatment Resource Center

Asphalt Distributors

Asphalt distributors are the most common piece of equipment used to apply prime coat to the base.  All distributors consist of several basic components including the material holding tank, a tank heating device, the distributor bar with nozzles, a network of pumps and valves to control material flow, and a computer to maintain constant shot rates.  To achieve a uniform distribution of the prime coat several factors must be controlled:

• speed of the distributor in feet per minute (ft/min or FPM)
• the flow rate from the pump in gallons per minute (gal/min or GPM)
• the spray width in feet and the nozzle type

All of these work together to achieve the desired application rate.  Fortunately, most modern distributors have an integrated flow rate computer that manages all of this information and maintains the proper application rate even if the speed of the distributor changes.  If the granular base is very dense or has been stabilized, the use of a scarification device, such as a field cultivator or dirt track grooming attachment, is recommended to allow the prime material to penetrate the surface of the granular base.  After scarification, the asphalt distributor is used to apply the prime coat and then a roller is needed to compact the scarified and primed surface.