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The calibration samples can be mixed after preparing the blank
sample. For the best measurement accuracy, each sample of
asphalt mixture (calibration and production testing samples)
should be the same weight (4 g).
After determining the % asphalt content (%AC) for the known
calibration sample (see example below), prepare the highest
%AC sample first. Fill the pan as full as possible, determine the
weight and prepare all samples at this weight (4 g).
Calibration samples are prepared by mixing a known weight of
hot, dry aggregate with a known weight of hot, liquid asphalt.
The number of calibration samples is optional and may vary
from two to twelve, with twelve providing the best accuracy.
Calibration samples should be prepared with the asphalt content
above and below the design content.
Example: If the Design Mix is 5.5% asphalt content and five
calibration samples are to be used, then the asphalt content of
the calibration samples should be 4%, 4.8%, 5.5%, 6.2%, and 7%.
Two methods for expressing the asphalt content percentage:
Method 1: % Asphalt by Aggregate Dry Weight
Method 2: % Asphalt by Total Mix Weight
where: A = % Asphalt Content
C = Dry Aggregate Weight
D = Weight of Mixing Bowl + Dry Aggregate
E = Total Design Weight
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