Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...
Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...
Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...
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4.3.6 Specific Gravity and Porosity<br />
4.3.6.1 Introduction. Specific gravity was measured by the displacement method <strong>in</strong> accordance with<br />
ASTM D792. The standard specifies that any convenient size specimen can be used for this test<strong>in</strong>g. A<br />
weigh<strong>in</strong>g scale (Figure 4-30) fitted with a hook at the bottom was placed on a bench hav<strong>in</strong>g a circular<br />
hole <strong>in</strong> the middle. A small wire basket was hung from the hook (Figure 4-31). A thermometer to<br />
measure the water temperature was hung from the bottom <strong>of</strong> the bench.<br />
Figure 4-30. Weigh<strong>in</strong>g Scale, Model<br />
Mettler PM200<br />
50<br />
Figure 4-31. Wire Basket and Thermometer<br />
A bucket full <strong>of</strong> water was placed on top <strong>of</strong> a screw jack. The screw jack helped <strong>in</strong> elevat<strong>in</strong>g the bucket<br />
and immers<strong>in</strong>g the specimen <strong>in</strong> water. A s<strong>in</strong>ker was also used to s<strong>in</strong>k the specimens. Details <strong>of</strong> the<br />
<strong>in</strong>strumentation are shown <strong>in</strong> Figure 4-32.<br />
Thermometer<br />
Bucket<br />
Screw<br />
jack<br />
Scale<br />
Figure 4-32. ASTM D792 Setup<br />
Bench<br />
The weight <strong>of</strong> each specimen was measured <strong>in</strong> air and water. The weight <strong>of</strong> the wire basket was also<br />
measured <strong>in</strong> water. Each time the immersed depth for the wire basket was kept identical. Specific gravity<br />
was calculated for each specimen us<strong>in</strong>g the equation provided <strong>in</strong> ASTM D792.<br />
The bulk specific gravity <strong>of</strong> the l<strong>in</strong>er comprises a mixture <strong>of</strong> res<strong>in</strong>, fabric, coat<strong>in</strong>g, and air. It is a useful<br />
measure to check whether the l<strong>in</strong>er meets the theoretical specific gravity based on the weighted<br />
contribution <strong>of</strong> its components. Low specific gravities typically <strong>in</strong>dicate higher porosities <strong>in</strong> the l<strong>in</strong>er.<br />
The results <strong>of</strong> the specific gravity measurements across all <strong>of</strong> the l<strong>in</strong>ers tested are discussed <strong>in</strong> Section 6.