Among polymer materials, high-density polyethylene (HDPE) is one of the most demanded polymers for packaging as well as in sectors with higher material requirements, such as the plastic pipe industry. The extensive use of HDPE means it is often present in municipal waste. Therefore, there is a high potential for reprocessing and exploring new applications for recycled HDPE, aiming for a circular economy. In the plastic pipe industry, recyclates have found practical use in non-pressure applications. However, the high structural and loading requirements do not allow using it for pressurized pipes yet. The presented study is focused on the possible utilization of recycled HDPE in pressurized pipes in the form of a layer in a multi-layer pipe with two protective layers made of virgin HDPE. The performance of the pipes is assessed based on numerical simulations, coupled with lifetime estimations. The lifetime assessment is based on linear elastic fracture mechanics using experimentally measured slow crack growth (SCG) rates in the virgin and recycled HDPE grades. Thanks to the numerical models, it was possible to describe damage by SCG of the multi-layer pipe as well as to find the dependency of the pipe performance on the thickness ratio and material properties of the layers.
Bibliographical noteFunding Information:
This work was supported by University Specific Research, project CEITEC VUT/FSI-J-23-8289 and by Polymer Competence Center Leoben GmbH (PCCL, Austria) within the framework of the K1 COMET-program, which is funded by the Federal Ministry for Transport, Innovation and Technology (Austria) and Federal Ministry for Economy.
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- High-density polyethylene (HDPE)
- Lifetime estimation
- Multi-layer pipe
- PE100 grade
- Recycled polyethylene
- Slow crack growth (SCG)