3.11.5
Mean Absolute Deviation
An example of the computation of mean absolute deviation for laboratory air
voids is as follows: Assume that the laboratory air voids are determined
from 4 random samples of a lot (where 3 specimens were compacted from each
sample). The average laboratory air voids for each sublot sample are
determined to be 3.5, 3.0, 4.0, and 3.7. Assume that the target air voids
from the JMF is 4.0. The mean absolute deviation is then:
Mean Absolute Deviation = (|3.5 - 4.0| + |3.0 - 4.0| + |4.0 - 4.0| + |3.7 -
4.0|)/4
= (0.5 + 1.0 + 0.0 + 0.3)/4 = (1.8)/4 = 0.45
The mean absolute deviation for laboratory air voids is determined to be
0.45. It can be seen from Table 7 that the lot's pay factor based on
laboratory air voids, is 100 percent.
Table 7.
Pay Factor Based on Laboratory Air Voids
Mean Absolute Deviation of Lab Air Voids from JMF
Pay Factor, %
O.60 or less
100
0.61 - 0.80
98
0.81 - 1.00
95
1.01 - 1.20
90
Above 1.20
reject (0)
3.11.6
In-place Density
3.11.6.1
General Density Requirements
For determining in-place density, one random core (100 mm 4 inches or 150 mm
6 inches in diameter) will be taken by the GovernmentEngineer from the mat
(interior of the lane) of each sublot, and one random core will be taken
from the joint (immediately over joint) of each sublot. Each random core
will be full thickness of the layer being placed. When the random core is
less than 25 mm 1 inch thick, it will not be included in the analysis. In
this case, another random core will be taken. After air drying in
accordance with ASTM D 2726 for laboratory-prepared, thoroughly dry
specimens, cores obtained from the mat and from the joints will be used for
in-place density determination.
3.11.6.2
Mat and Joint Densities
The average in-place mat and joint densities are expressed as a percentage
of the average TMD for the lot. The average TMD for each lot will be
determined as the average TMD of the two random samples per lot. The
average in-place mat density and joint density for a lot are determined and
compared with Table 8 to calculate a single pay factor per lot based on
in-place density, as described below. First, a pay factor for both mat
density and joint density are determined from Table 8. The area associated
with the joint is then determined and will be considered to be 3 m 10 feet
wide times the length of completed longitudinal construction joint in the
lot. This area will not exceed the total lot size. The length of joint to
be considered will be that length where a new lane has been placed against
an adjacent lane of hot-mix asphalt pavement, either an adjacent freshly
paved lane or one paved at any time previously. The area associated with
SECTION 02749
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