Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...

5.3.6.3 Laboratory Measurements. For determining the liner thickness in the laboratory, specimens
cut out from the liner sample for the ASTM tensile and flexural tests were used. Six specimens were used
and five readings were taken for each of the specimens using a micrometer. The average calculated
values and their standard deviations are shown in Figure 5-35. The original design thickness stated in the
figure was not known, but it was assumed to be 15 mm based on the thickness used for the adjacent liner.
The weighted average for the sample thickness measurements was calculated to be 11.9 mm and the
weighted error ±0.3 mm. The laboratory measured values were 16% lower than the field measured
values.
Figure 5-35. Laboratory Measurements of Thickness for the Columbus 36-in. Liner
5.3.7 Specific Gravity and Porosity. Seven specimens from the downstream sample were used to
determine the specific gravity of the liner. The average specific gravity for the sample was calculated to
be 1.17 with a standard deviation of 0.06.
Measurements of density and porosity of a sample from this liner specimen were made by Micrometrics
Analytical Services. In their testing (using mercury penetration for the porosity determination), the bulk
density (at 0.54 psia) was 1.0884 g/mL, the apparent (skeletal) density was 1.3233 g/mL, and the porosity
was 17.752%. The full test report is provided in Appendix C and a discussion of the specific gravity
across all the retrospective site samples is provided in Section 6.
5.3.8 Flexural Testing. Specimen cutting and preparation for testing in accordance with ASTM
D790 follows the procedures described for the other liner specimens. Table 5-13 shows the dimensions
and moment of inertia for the specimens.
Using the information in Table 5-13, the flexural stress and strain data for all samples was drawn (Figure
5-36). Peak load, peak shear stress, and flexural modulus values for each specimen, obtained using the
software ‘MtestW’, are listed in Table 5-14.
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