How is the spread rate of tack calculated?

The spread rate of tack is calculated by taking the number of gallons used at a temperature of 60°F and dividing it by the square yards covered. This specific temperature is significant because it is often considered the standard for many paving applications, ensuring that the tack coat adheres properly to the underlying surface.

Using 60°F allows for consistent behavior of the tack coat material, as temperatures can impact the viscosity and spreading characteristics of the asphalt. Therefore, standardizing the measurement at this temperature provides more reliable and reproducible results, which is crucial in ensuring that paving operations are effective and meet quality control standards.

In essence, calculating the spread rate at 60°F helps establish a baseline for assessing the proper application of tack coat materials, ensuring optimal bonding between layers in the asphalt paving process.