The corrugated hose made of plastic is a recently developed material that offers several advantages over the traditional metal corrugated pipe. High-density polyethylene (HDPE) is the primary raw material used in making the plastic corrugated pipe, which boasts excellent corrosion resistance properties compared to metal. Unlike metal, plastic does not corrode on its own nor does it get affected by acidic or alkaline substances, thereby providing a much stronger protective layer to prestressed tendons from corrosion. This is especially important for prestressed structures that could be exposed to harsh external conditions like seawater and deicing salts that may cause micro-crack leaks or drain blockages leading to corrosion. Plastic bellows are particularly useful in these environments since they provide a robust barrier against harmful substances. Moreover, the plastic wave tube's friction coefficient is much lower than that of the metal bellows, reducing the friction loss of prestress during the tensioning process. This, in turn, enhances the durability and performance of post-tensioned prestressed structures.
The friction coefficient of plastic bellows typically measures at 0.14, whereas metal bellows measure at 0.25. Nevertheless, plastic bellows present higher strength compared to the metal version, making them resistant to trampling, chiselling, and vibration. They also exhibit superior sealing property and are less prone to leakage, thus proving to be excellent for vacuum grouting. Besides, plastic bellows are non-conductive, which makes them ideal for preventing stray current corrosion. In contrast, metal bellows is an efficient conductor of electricity. Additionally, plastic bellows' fatigue performance is better, providing improved resistance to the component's eventual fatigue.