Troxler Enhanced RoadReader Plus 3451, Manual Of Operation And Instruction

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Model 3451 4–7
PREPARING A TEST SITE
To ensure measurement accuracy, properly prepare the test site
before taking gauge measurements. This section describes how to
prepare test sites properly for
direct transmission and backscatter
measurement modes. For a description of these measurement
modes, refer to page 2–2.
DIRECT TRANSMISSION MODE
Direct transmission mode is used on materials with layers four
inches thick or more. This mode is most commonly used on soils,
but can also be used to measure asphalt and concrete.
✓
Locate a smooth site on the test material free from any large
holes, cracks, or debris.
✓
If necessary, smooth the surface by moving the scraper plate in
a back and forth motion.
✓
Fill any voids or depressions with fine sand. Strike off any
excess fill.
✓
Place the scraper plate back on the surface and press down
slightly to level the surface.
✓
Drill a hole in the test material as follows:
✓
Put the drill rod through the extraction tool and then through
one of the guides on the scraper plate (Figure 4–5).
✓
Wear safety glasses and a radiation dosimeter.
✓
Place the drill rod assembly on the test site.
✓
Step on the scraper plate.
✓
Hammer the drill rod at least fifty millimeters (2 in.) deeper
than the desired test depth. The drill rod increments include
the additional depth.
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