Barrier Protection of Plastic Bellows and Wiring Harness Bellows
The raw material of plastic bellows is HDPE. Its corrosion resistance is far better than that of metal, it is not afraid of acid and alkali corrosion, it does not corrode itself, and can effectively protect the tendons from corrosion. Many structures are subject to severe external influences, such as deicing salts or salt water. When the post-tensioned member collapses or fails due to the collapse of the waterproof layer, leakage of micro-cracks and drainage facilities, the tendons may be corroded. Metal pipes do not have a permanent anti-corrosion ability, which is not enough to resist water leakage and reach the slurry and tendons. The plastic bellows can provide a tendon with a barrier protection effect that is far superior to that of metal bellows. It can prevent harmful substances from penetrating the pipeline to pollute, thereby ensuring better durability of post-tensioned structures. Plastic bellows is a new type of hole-forming material based on HDPE.
It is mainly used in post-tensioned pre-stressed cement structures. The rods have holes, and have good tightness, no seepage leakage, high ring stiffness, small friction parameters, aging resistance, electrical erosion resistance, good soft elasticity, and are not easy to be punctured And the new connection method makes the construction connection more convenient. When the hole-forming material is damaged, the paddle vacuum bellows is the last protective barrier of the steel plate in the cement structure. Plastic bellows are used in post-tensioned pre-stressed concrete structures as hole-forming pipes with pre-stressed tendons.
- It has good corrosion resistance and improves the corrosion protection of tendons.
- It has good physical properties, non-conductive, can prevent stray current corrosion, good sealing performance, and does not rust; it does not penetrate under load; high strength, high rigidity, good impact resistance, not afraid to step on.
- Reduce pre-stressed friction loss during tensioning. Pre-stressed bridge bellows are a plastic bellows and a metal bellows. The performance of plastic bellows is compared with galvanized bellows. Plastic bellows galvanized bellows. Corrosion resistance polyethylene is the most stable chemical product in general plastics. It never rusts and has good rust resistance after galvanizing, but the galvanized layer easily reacts with the alkali cement slurry and precipitates hydrogen. The strength and the adhesion of the concrete have a bad effect. The aging time is up to 50 years under the condition of durable cement packages. The service life is generally about 5 years. The minimum bending radius is 0.9-1.5 (about 10-15 times the inner diameter or the long and short axis). The round pipe is greater than 30. The tube with double inner diameter is greater than 30 times the resistance of the long- or short-axis local load of the vacuum fitting in the bending direction. The load will not leak after the load is applied, and there will be no worries about bending and leakage. The pipe cannot be recovered after deformation. Capable pipe wall thickness is 1.5-2mm, arranged in a single ring, with high rigidity, not afraid to be stepped on, and not easy to be punctured by vibrators. The pipe wall thickness is 0.2mm-0.4mm, which is arranged in a spiral, with relatively small stiffness, and easy to step on. Deformation, pouring when condensing soil, the vibrating rod cannot touch the bellows. The pipe is continuously extruded without fracture. The humidity, humidity is 20 degrees, and the pressure is 50 kpa. The steel strip is 0.2-0.4 folded and engaged for 24 hours without leakage. Water will leak under the action, and cement will seep under the action of pressure.
Harness bellows is a new type of pipe with a ring-shaped outer wall and a smooth inner wall. It was first developed in Germany in the early 1980s. After more than ten years of development and improvement, it has developed from a single variety to a complete product series. At present, it is very mature in production technology and use technology. Because of its excellent performance and relative economic cost, it has been greatly promoted and applied in developed countries such as Europe and the United States. In China, the promotion and application of wire harness bellows is in the rising trend stage, and all technical indicators have reached the use standards.
