Lesson 6/Learning Event 4
FIGURE 23. SCREEN OPENING SIZE VERSUS CAPACITY
Step 5. Determine the Plant Output.
In most cases, the dryer capacity will determine the plant output. Other considerations
include ability of laydown crew to handle anticipated tonnage, number of haul units available,
distance of haul, dryer capacity, and screening capability of the gradation unit.
To determine the plant output, the percentage of dried aggregate that will be used in the
total mix must be determined. If no mineral filler is added at the fines feeder, the percentage of
bitumen subtracted from 100% will give the percent of dried aggregate.
Example: Percent bitumen 6.0%
Therefore: Percent aggregate = 100 - 6 = 94% dried aggregate
total mix
If mineral filer is added after drying, subtract the percent bitumen from 100% to get the
percent of total aggregate. Subtract the percent of mineral filler (expressed as a percent of total
aggregate) from 100%. Multiply the two results to obtain the percent of dried aggregate in the
total mix.
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