Troxler 4640-B, Руководство по эксплуатации и инструкция

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SURFACE VOIDS
In cases where thin layer measurements must be taken on asphalt
mixes containing large aggregate (open mixes), the
surface voids
mode may be enabled to obtain a more accurate reading. Refer to
Figure 6–1 on the following page to aid the decision of
surface
voids mode usage.
When measuring a thin layer containing large aggregate, the gauge
bottom will not make uniform contact with the asphalt surface. The
resulting “air voids” may shift or bias the density readings. In
surface voids mode, the 1-inch magnesium reference block is placed
under the gauge to remove the air voids between the gauge and the
road surface (see Figure 6–2). The readings calculated will reflect
the bulk density of the top 3 in. (8 cm) of the material under the
block and will be unaffected by the thickness setting of the gauge.
NOTE
In most cases, a special calibration will provide
satisfactory readings on large aggregate mixes. If the
user suspects that the gauge readings are skewed,
perform a special calibration. Refer to page 5–5 for
more information.
To enable the
surface voids mode press
〈
SHIFT
〉
and
〈
SPECIAL
〉
.
Press
〈
1
〉
.
-SURFACE VOIDS-
DISABLED!
Do you want to
Enable ?
The display returns to the
Ready mode.
6–2