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

3.4.1 Additional Testing Concepts. As the protocols were further developed in discussion with
the City of Denver and the City of Columbus, some additional avenues for testing or evaluation were
proposed either by the City or the research team. These are listed in Table 3-4 together with comments on
the potential value of the testing, expected difficulties in testing or interpretation, and the use of the
testing in the current pilot project. The main area of interest was to try to identify potentially useful new
approaches that could provide an indication of any liner deterioration – either NDT methods that could be
deployed within a pipeline or destructive methods that only required a small sample of liner material.
Such tests could then be correlated with the standard tests in this study to see if a relationship appeared to
resist. If so, then the promising tests could be evaluated further in future projects to fully establish the
validity of the approach.
Table 3-4. Additional Testing/Evaluation Concepts Considered
Test Description Potential Value Difficulties Application for pilot study
Thermo-
Gravimetric
Analysis
(TGA)
Fourier-
Transform
Infrared
(FTIR)
Spectroscopy
Compression
Strength
Testing
Measures the
weight loss of
the sample as it
is heated to show
the temperatures
at which
degradation
takes place.
Identifies the
nature of
chemical bonds
and the
crystalline
phases that
formed in the
material.
Provides a
material strength
parameter.
Fractography Examines
fracture surfaces
under a
Rebound
(Schmidt)
Hammer
Chemical-
Resistance
microscope.
Data on surface
properties and
shallow
delaminations.
Used principally
for concrete
materials.
Measures the
strength loss of
samples that
have been
exposed to
chemicals.
This provides information
about the organic
components and could
identify degradation of the
CIPP material. Again,
comparison of surface
material versus core
material and/or control
samples would be useful.
If the resin is known, or if
samples of the resin are
available, spectra from the
field samples can be
compared to the resin. If
controls are not available,
spectra can be examined
for signs of degradation
such as oxidation products.
Would provide values for
comparison with flexural
and tensile test values.
Gain insight into what type
of failures are occurring in
liner materials.
Might provide insight into
surface deterioration of
liner materials and/or
evidence of delamination
in thin liners.
Would determine if the
specimens were still in
compliance with the
chemical-resistance
requirements of Table X2.1
of ASTM F1216.
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The challenge is
developing a
testing protocol
that accounts for
the VOCs
common to many
resins used in
CIPP
installations.
Preliminary tests during this
study did not yield
interpretable data,
potentially due to too high
temperature gap
None. Not used. One challenge for
a retrospective evaluation is
obtaining good control
samples for virgin materials
that may no longer be on the
market. Raman
spectroscopy was used for
the purposes of this study.
Liner thickness
and curved shape
not suitable for
compression test.
Complement to
other testing to
failure.
Current
equipment too
large to use in
small dia. pipes.
Value of
measurements
unclear.
Not used.
Not used.
None. Not used.
Not followed up at this time.
Shore and Barcol surface
hardness measurements
made instead.