Model 3440 4–29
Lift the gauge from the test site by the source rod handle.
This returns the source rod to the SAFE position, where it
should stay when not taking readings.
Asphalt Mode
The Asphalt mode is automatically selected when a Gmb value is
enabled (see page 3–9).
To measure the density of asphalt (and hardened concrete of 4
inches or more), follow the steps below:
Select the Asphalt mode (see page 3–14).
Enter or enable the Marshall value and/or voidless density
value (see Chapter 6).
Prepare the test site as described on page 4–22.
Place the gauge on the test area.
Lower the source rod to the backscatter position (just below
the SAFE position). Release the trigger.
Gently push the handle down to lock the source rod into
position. You should hear a click when the source rod locks
into position.
Press the ¢START² key.
f In the Manual depth mode (see page 5–3), the gauge
prompts for the source rod depth. Enter the source rod
depth using the number keys. For example, with the
source rod in the backscatter position, press ¢0², and
then press ¢ENTER/START².
f In the Automatic depth mode, the gauge software
determines the source rod depth automatically.
After the count time has elapsed, the gauge displays the
measurement results in a series of three screens, Use the up
and down arrows to scroll through the various screens.
%Gmb= ###.# ↨
WD= ###.#
M= ##.# %M= ##.##
%Voids= ###.#