Comprehensive Understanding of Corrugated Plastic Duct

Comprehensive Understanding of Corrugated Plastic Duct

Summary

Prestressed plastic corrugated pipes are widely used in the construction of railways, bridges, etc. due to their advantages of aging resistance and electrical corrosion resistance. The following briefly introduces the advantages and precautions of corrugated plastic ducts.

The corrugated plastic duct is HDPE as raw materials, mainly used in the posterior prestressed cement structure, pull the hole, with good sealing, no seepage leakage, high ring stiffness, small friction parameters, aging resistance, electric corrosion resistance, flexible elastic, not easy to be smashed and new connection way to make the construction connection more convenient.

Corrugated plastic ducts are mainly used in highways, railways, bridges, slopes, high-rise buildings, and other large-span tension project construction. The following briefly introduces the advantages of the corrugated plastic ducts and how to prevent wear.

What are the advantages of corrugated plastic ducts?

A circular corrugated plastic duct is a new type of hole-forming material. Compared with metal duct, it has the following advantages:

1. The raw material of corrugated plastic duct is HDPE. Its corrosion resistance is far superior to that of metal, it is not afraid of acid and alkali corrosion 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 saltwater.

When the post-tensioned members are due to the collapse of the waterproof layer, the leakage of micro-cracks, and the blockage or failure of the drainage facilities, the prestressed tendons may suffer from corrosion effects. The corrugated plastic duct can provide a barrier maintenance effect far superior to the metal bellows for the prestressed tendons, which can avoid the pollution of harmful substances penetrating the pipeline, thus ensuring better durability of the post-tensioned prestressed structure. Bridge prestressed corrugated plastic duct.

2. The corrugated plastic duct is non-conductive, which can avoid stray current corrosion, and metal is a good conductor of electricity;

3. Under the same conditions, the conflict coefficient of the reserved hole of the prestressed plastic corrugated pipe is significantly smaller than that of the reserved hole of the metal corrugated pipe, which reduces the conflict loss of prestress in the tensioning process.

In general PVC corrugated plastic duct, the conflict coefficient of the corrugated plastic duct is 0.14, and the conflict coefficient of the metal corrugated duct is 0.25; the strength of the corrugated plastic duct is high, and it is not afraid of stepping on, and it is not easy to be vibrated. Prestressed corrugated ducts, whose sealing function and anti-leakage function are higher than metal corrugated ducts and plastic corrugated ducts, are more suitable for vacuum grouting;

Fourth, the prestressed corrugated duct has better durability and can greatly improve the fatigue resistance of the components.

How do prestressed corrugated ducts prevent wear?

Prestressed corrugated duct after welded corrugated pipes produces great thermal stress in the weld area. It can prevent the precipitation of carbide along the austenite crystal boundary, and the formation of chromium-poor areas. In order to eliminate and redissolve the precipitated carbide, high-temperature tempering disposal is necessary.

The addition of titanium to the alloy tube can prevent the precipitation of carbides along the grain boundary, and then make it precipitate along the grain boundary, without causing the precipitation of ChQ along the grain boundary, and without the appearance of chromium-poor areas. It can be eliminated by stabilization treatment such as solution normalizing.

The choice of ignition temperature should meet two conditions: the dissolution temperature higher than chromium carbide and lower than that of titanium carbide; the temperature of Cr23C6 all dissolved in the alloy tube, as much as possible, thus not forming a chromium poor zone, greatly reducing the tendency of intercrystalline corrosion.

Matters needing attention when tensioning prestressed plastic corrugated duct.

When the prestressed plastic corrugated duct is stretched, the concrete will be deformed. Therefore, the amount of deformation and the direction of deformation must be fully grasped during tensioning, and it is necessary to strictly check whether the template and the bracket have places that restrict the deformation. 

Check the supporting equipment for tensioning work to ensure that there are no problems and errors in all supporting facilities. Develop safety measures for the tensioning process of the plastic corrugated duct. Check whether the specifications and varieties of steel bars and anchor fixtures conform to each other.

According to the site and construction method, the prestressed plastic corrugated pipe decides whether to use two-end tensioning or one-side tensioning, and the method of tensioning and prestressing should be clearly planned in advance and then implemented.

If the order of tensioning cannot be determined, follow the uniform countermeasures and the principle of small eccentric load, which can be determined by the following methods: 

First tension the steel bundles close to the section to avoid excessive tensile stress in the concrete, and then tension from top to bottom For the steel bundles at the beam end, in order to prevent the beam end from generating a large eccentric load, after stretching one end, the other end must be stretched. If there are three rows of steel bundles at the beam end, the steel bundles in the middle row should be stretched first, and then tensioned. The left and right steel bundles are crossed for tensioning.

The above introduces the benefits of prestressed plastic corrugated ducts and the problems that need attention. If you have any questions or want to buy prestressed plastic corrugated ducts, please contact us.

CHENPENG is a China custom pc stranded wire and post-tension tube supplier. Our company was established in 1994, specializing in the production of the following products: Air Ducts: Metal and HDPE types, 4 production lines, with an annual output of 6 million meters. PC stranded wire: 2/3/7/19 wire PC stranded wire, diameter from 4.85mm to 23mm, 13 production lines, annual output of 220,000 tons. Anchors: round and flat anchor heads, load-bearing plates, wedges and spiral reinforcements, 3 production lines, with an annual output of 7 million holes, etc. 

With our 26 years of production and export experience, Chunpeng has become a major partner for government projects at home and abroad.