How is the spread rate for BASE asphalt calculated?

The calculation of the spread rate for BASE asphalt involves determining how much asphalt is needed to achieve a specified thickness over a given area. The formula used combines the thickness of the asphalt layer, the specific gravity of the mix (gmm), and a conversion factor. In this case, the correct formula multiplies the thickness by the gmm and uses 43.3 as the conversion factor to yield the spread rate.

Introducing the value of 43.3 relates to how asphalt density is considered in the context of paving applications, ensuring accurate material estimation for surface coverage. The choice utilizes established industry standards for asphalt density and reflects typical practice for ensuring that the coverage is not only effective but also minimizes waste.

The other options present various incorrect forms or factors. For instance, different multipliers like 40.5, 50.0, or 45.0 do not correspond to the accepted industry standards or calculated values for the specific density and thickness combination. Therefore, the choice that utilizes 43.3 effectively and accurately addresses the calculation needs for BASE asphalt spread rate is the most appropriate answer.