Corrugated Plastic Duct for Post Tensioning
Prestressed plastic corrugated duct is a single-wall corrugated duct extruded from high-density polyethylene (HDPE), which is used for post-tensioned prestressed concrete structures and is a new type of prestressed pore-forming material. It is an ideal product to replace the original metal ducts in bridge and building construction.
Plastic corrugated ducts are divided into two categories: round ducts and flat ducts. In actual use, it is supplemented by various plastic couplers to connect.
The raw material of prestressed plastic corrugeted ducts is HDPE. Compared with other ducts, prestressed plastic corrugated ducts have many advantages.
The corrosion resistance of prestressed plastic corrugated ducts is far superior to that of metal, and it is not afraid of acid and alkali corrosion. It does not corrode itself, and can effectively protect the prestressed tendons from corrosion. Many prestressed structures are subjected to severe external influences, such as deicing salt or salt water. Prestressed tendons may be subject to corrosion when the post-tensioned member is subject to corrosion due to the collapse of the waterproof layer, the leakage of micro-cracks and the blockage or failure of the drainage facilities. Grouting of Tendons in Prestressed Concrete in FIP Construction points out that metal ducts have no permanent corrosion resistance and are not enough to resist water leakage and reaching the grout and prestressing tendons. The prestressed plastic corrugated ducts can provide a barrier protection far superior to the metal ducts for the prestressed tendons. It can prevent the pollution of harmful substances penetrating the channel, thus ensuring the resistance of the post-tensioned prestressed structure.
Under the same conditions, the friction coefficient of the reserved hole of the prestressed plastic corrugated ducts is obviously smaller than that of the reserved hole of the metal ducts, which reduces the friction loss of the prestressing during the tensioning process. Generally, the friction coefficient of plastic corrugated ducts is 0.14, and the friction coefficient of metal ducts is 0.25.
The prestressed plastic corrugated duct has high strength, is not afraid of stepping on it, and is not easy to be broken by vibrating and holding. Its sealing performance is also relatively good, and it does not penetrate under a certain load.
Prestressed plastic corrugated ducts have good physical properties, are non-conductive, prevent stray current corrosion, and do not rust.