Prestressed concrete
is not a genuine building material but a way of manufacturing posts in order to use the qualities of compression in the application of the concrete.
The post is prestressed in the manufacturing process. There are several ways to prestress the post: the most common is based on the following procedure and is performed in a factory.

The prestressed concrete posts are produced on a 60 metre long frame using the “pre-tensioned” braid technique.
Before the liquid cement is added, the frame is prepared with braids held in position by an external machine making it very strong - close to the steel safety threshold.
These braids are specifically made of harmonic steel in order to improve cohesion.

At this point the concrete is added to the frame and the cast is left to partially solidify (usually only a few hours with the use of steam). Once the concrete is strong enough, the machine holding the braids gradually releases them and they return to their original form (which of course, under traction had been stretched from a few millimeters to some metres in length) thereby translating the force of the traction received by virtue of compression to the concrete.

The posts are then removed from the frame.

Prestressed Cement Post Production

Prestressed CEMENT POSTS production