When paving with asphalt, you normally purchase liquid asphalt and mix it with an aggregate such as gravel or crushed rock before laying it down. Liquid asphalt is commonly sold in tons or pounds. If you are purchasing large quantities of asphalt, you often will have to convert the tonnage or poundage into gallons to get the correct amount for your project.
Find out the specific gravity of the liquid asphalt. Your supplier should be able to give you this information. It also should be listed on the delivery ticket when you buy the asphalt. The specific gravity of a substance shows how dense it is compared to water, which has a specific gravity of 1. Liquid asphalt is denser than water, so its specific gravity will be greater than 1.
Divide the specific gravity of the liquid asphalt into 8.328 (pounds of water per gallon) to get the pounds of asphalt per gallon. For example, if the specific gravity of the asphalt is 1.03, divide 8.328 by 1.03 to get a result of 8.085 gallons of asphalt per pound.
Multiply the gallons of asphalt per pound by 2,000 to get the gallons of asphalt per ton. For example, if the particular liquid asphalt gives 8.085 gallons per pound, multiply 8.085 by 2,000 to get 16,170 gallons of asphalt per ton.
Multiply the gallons of asphalt per ton by the number of tons to get the tonnage in gallons.