About

Concrete in which permanent internal stresses are deliberately introduced, usually by tensioned steel, to counteract the desired degree of the stresses caused in the member in service is called prestressed concrete. The method of prestressing concrete in which prestressing steel is tensioned against the hardened concrete is called "Post-Tensioning".

Post-tensioning is a method of reinforcing (strengthening) concrete or other materials with high-strength steel strands or bars, typically referred to as tendons. The materials used to post-tension concrete members are ultra-high-strength steel strands and bars. The steel reinforcing strands are installed in a way that protects them from bonding with the concrete.

A mono-strand tendon consists of a seven-wire strand that is coated with a corrosion-inhibiting grease and encased in an extruded plastic protective sheathing. The anchorage consists of an iron casting and a conical, two-piece wedge which grips the strand.