Asphalt yield is the tons of hot mix a job actually used, added up from the plant tickets, divided by the tons the estimate figured from area, depth and unit weight.
A yield of 1.10 means the crew placed 10 percent more mix than the formula said. The extra tons come from a short list: depth creep at the screed, ruts and low spots in the old surface, hand work at edges and structures, mix left in truck beds and the hopper, and a real unit weight that isn't the 145 you assumed.
It's often the biggest material variance on a paving job, and it's easy to miss. The tickets come in over several days, and the invoice matches the proposal no matter how many tons went down.
Work it out on every job and group it by type: overlay, mill and fill, new construction. After a season, those numbers are your waste factors, and they'll beat any rule of thumb.