What is post tensioning?

Post tensioning method refers to the construction method of pouring concrete first, and then tensioning the prestressed steel to form a prestressed concrete component after reaching more than 75% of the design strength

Fabrication of members: firstly, the members shall be fabricated, and corresponding holes shall be reserved in the members according to the position of the prestressed reinforcement. After the concrete strength of the members reaches the specified strength, the prestressed reinforcement shall be inserted into the reserved holes for tensioning;

The prestressed reinforcement after tensioning is anchored at the end of the component by the anchorage device, and the pretensioning force of the prestressed reinforcement is transmitted to the concrete by the anchorage device at the end of the component, so that the prestressed stress is generated; Finally, cement slurry is poured into the duct to make the prestressed reinforcement and concrete members form a whole.

Features

1. Good fluidity: the fluidity of discharged slurry is 18 ± 4 seconds, and after 30 minutes, the fluidity is less than 30 seconds;

2. Good stability: the slurry does not layer and precipitate, forming a stable fluid;

3. No shrinkage performance: the slurry has no shrinkage or slight expansion performance, and has good adhesion with the prestressed duct;

4. High filling degree: it has good filling performance, and can completely fill the entire channel;

5. High strength: high early strength and late strength, including flexural strength and compressive strength, which can reach 70% of the design strength in 7 days.

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The differences between post tensioning System and Pretensioning System

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