The asphalt application rate shown on the plans is intended primarily for estimate purposes. The actual application rate should be based on several design variables as discussed in Chapter 4.

If asphalt cement is to be applied at 0.36 gallons per square yard, this rate should be sprayed from the distributor. If emulsion is to be applied at a residual rate of 0.36 gallons per square yard, this is the residual amount of asphalt desired and not

the amount to be shot from the distributor.

Emulsions consist of asphalt cement, water, and an emulsifying agent. After the emulsion is sprayed on the roadway, the water evaporates (the emulsion breaks), leaving only the asphalt cement. Various types of emulsions contain different amounts of water and emulsifiers. Typically, an emulsifying agent and water are 35 to 40 percent of the total emulsion. Therefore, an emulsion to be applied at a residual rate of 0.36 gallons per square yard with 60 percent residual asphalt should be sprayed at a rate of 0.60 gallons per square yard (0.36/0.60). The percentage of residual asphalt for any emulsion can be obtained from the district asphalt laboratory or the emulsion supplier.