Troxler 3411-B, Manual Of Operation And Instruction

Page: 38 / 109

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Density Correction
The 3400 series is calibrated for soils, aggregates, concrete, and
asphalt with a density range of 1100 to 2700 kg/m
3
(70 to 170
pcf). Corrections to the density calibrations are only necessary
in rare conditions such as work involving industrial waste, mine
tailings, and coal. For a general discussion of calibration, see
page A-10. If working with coal, see page 5-14. For other
applications, contact your Troxler representative.
Moisture Correction
The 3400 series measures moisture by determining the
hydrogen (H) content of the soil and relating this to water (H
2
0)
content. In some soils there are compounds other than water
that contain hydrogen. There are also elements in some soils
that absorb neutrons, thereby lowering the count rate.
The 3400 series gauges are calibrated for soils without neutron-
absorbing elements or components other than water containing
hydrogen and need not be adjust for most soils.
To determine a correction factor, use the following procedure:
1.
Take five or more oven dry and gauge sample pairs. Be sure
oven dry samples are at least 1000-2000 grams taken under
the center of the gauge to a depth of 15-20 cm (6-8 in.). Be
sure nuclear tests are taken with the Moisture Correction
set at 00 on the 3411-B keypad.
2.
Prepare a chart as shown below.