State the term - Post-tensioned concrete

In Post-tensioned concrete construction, as shown in Figure,  tendons are placed inside concrete and stretched after concrete has attained sufficient strength. In this form of  construction, ducts are made inside concrete with the help of  tubes or pipes, which are provided in the forms at the time of casting of concrete. After sufficient hardening of  concrete, tendons are placed in these ducts, stretched from both ends from outside with the help of jacks or other suitable devices and anchored at the ends of  the concrete member. After the anchorage of  tendons, tensile force of tendons is transferred to the concrete in the form  'of an equal compressive force. This compressive force, upto its capacity, reduces or eliminates the tensile stresses (produced due to external loads) in concrete.