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Non-destructive testing and mechanical characterization of thermosetting polymers used in pipeline rehabilitation

: Manavipour, Maryam
: Boller, Christian

Saarbrücken, 2018, 155 pp.
Saarbrücken, Univ., Diss., 2018
Fraunhofer IZFP ()
cured-in-place pipe (CIPP); PET; unsaturated polyester resins (UPR); thermogravimetric analysis (TGA); dynamic mechanical analysis (DMA); Fourier Transform Infrared (FTIR); Differential Scanning Calorimetry (DSC); aging; curing

Cured in place pipe (CIPP) is one of the trenchless methods of pipe rehabilitation, by inserting a new polymeric liner inside the host pipe. Different abnormalities may occur during manufacturing, curing, inserting and operation in CIPP, which may reduce its efficiency; therefore regular inspection is necessary. Nowadays these inspections are only through destructive methods. In this thesis, the non-destructive testing (NDT) is applied, such as microwaves, terahertz and ultrasound immersion techniques for investigation these abnormalities. As the CIPP is exposed to water after installation, the effect of hydrothermal aging was investigated here. The aging was performed by immersion of CIPP samples in double distilled water at 65 °C until the samples get saturated. The saturation process was controlled through weighing. The inspection of aging was performed via comparison of optical microscopic images before and after aging and also through nanoindentation tests. It was shown that the mechanical aging is the reason of the mechanical properties degradation. Moreover, microwaves and terahertz techniques could distinguish aged samples from the unaged ones. These methods and ultrasound technique could detect the insufficient curing and geometrical defects in CIPP. Besides, the thickness measurement through these methods was possible. In summary NDT has a good outlook for analysis of CIPP and in the future it can be an alternative to destructive testing in this region.