Model 3440-L 5–3
5. 3440 OPERATIONS
OFFSETTING A READING
The Troxler 3440-L Gauge is factory calibrated for soils, asphalt, and
concrete. The operator can adjust gauge readings based on other
performance test, such as control strip results, core samples, or sand cones.
This adjustment, or shift, is known as an offset.
NOTE
When an offset has been enabled, all future readings will
automatically be adjusted with the offset factor regardless of
the test site. It is very important that the operator DISABLE
the offset function prior to taking readings on materials that
do not require an offset
. Offset functions will be disabled if the
gauge is turned off for more than 10 seconds.
The 3440-L gauge provides offsets for the following measurement types:
♦ Wet density measurements
♦ Moisture measurements
♦ Trench measurements
Offsets may be required for an accurate measurement if the material to be
measured meets any of the following conditions:
♦ Has a density outside the range of 70 to 170 pcf (1100 to 2700 kg/m
3
)
♦ Has a high concentration of elements with atomic numbers greater
than 20 (such as concrete, some coals, or ferrous soils)
♦ Is high in a hydrogen-rich material (such as gypsum, coal, or lime).
The 3440-L gauge also requires an offset if measurements are to be taken
inside a trench or close to a structure. The walls of the trench or structure
may scatter the gamma photons and neutrons back to the gauge, resulting
in inaccurate density or moisture readings.
To enable the Offset function, press 〈OFFSET〉 to display:
-OFFSET- Select:
1-Dens. -OFF-
2-Moist. -OFF-
3-Trench -OFF-
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