Transtech PQI 301, Operator'S Handbook Manual

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3.6 Calibration
Calibration is necessary for accurate and consistent readings. The PQI must
be calibrated for each asphalt mat at each job site. The PQI determines
HMA density by measuring a property of the HMA mat and comparing it
to a measurement of that property at a known density. The property that the
PQI measures varies for different HMA mixes. Therefore, to obtain accurate
density readings, the PQI must be calibrated for the mix that is currently being
measured. Once calibrated for a specific mix, the calibration factors (called
slope and offset) will remain valid and can be reused at a later date if that mix is
used again.
The PQI provides a number of different calibration methods which can be used
under different circumstances. The following table briefly describes the different
methods:
Method Description
Normal Convenient method for adjusting offset after
PQI readings have been taken and cores have
been obtained from those reading areas. Simply
enter the amount that the PQI is reading too
high or low relative to the core readings.
One Point Method Quick calibration estimate that can be used by
(Factory Use Only) taking a reading of the unrolled mat and
entering the expected percent compaction at
that point.
Two Point Method Quick calibration estimate that can be used
(Factory Use Only) by taking readings of the unrolled mat and a
peaked area of the finished mat entering the
expected percent compaction at those points.
Manual Slope Allows you to type in a numeric value for the
(Factory Use Only) slope calibration constant.
Calibration Menu
1) Normal
2) Special (Factory use only!)
ENT) Exit
To access the calibration methods, press the “CAL” key while the PQI is
operating in one of its run modes. The following screen will appear:
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