Evaluation of the physical, chemical, mechanical, and thermal properties of steam-cured PET/polyester cured-in-place pipe

Cured-in-place pipe (CIPP), a popular trenchless technology, has gained wide attention for drinking water, sewerage and storm water pipe rehabilitation because of its ease of installation. Here, the physical and thermal properties of steam-cured PET felt/polyester resin CIPPs were studied. ¹H NMR and GC-MS analysis was performed to identify the unreacted volatile organic compounds in cured CIPPs and results were compared to uncured resin and laboratory cured liner characterizations. Results indicated that organic chemicals in cured CIPP altered the mechanical properties and may be leached out with water. Significantly, lower porosity, density and amount of unreacted volatile organic compounds were much less in the CIPP's inner layer as compared to its outer layer. Water conditioning was conducted to investigate the influence of water on CIPP physical and mechanical properties. No changes were observed for density and porosity for either the CIPP's inner and outer layer; however, the flexural modulus increased slightly due to unreacted organic chemical leaching from the CIPPs.