In a post-tensioned prestressed concrete beam, what are the two primary time-dependent losses of prestress force, and how do they fundamentally differ in their origin?

In a post-tensioned prestressed concrete beam, the two primary time-dependent losses of prestress force originating from the concrete itself are Creep of concrete and Shrinkage of concrete. Both phenomena lead to a reduction in the initial tension applied to the prestressing tendons over an extended period. Creep of concrete is the long-term, time-dependent deformation or shortening of concrete under sustained compressive stress. Its fundamental origin lies in the viscous flow of the cement paste within the concrete, the gradual rearrangement of its internal microstructure, and the slow movement of adsorbed water under a constant load. When the concrete in the beam is subjected to the continuous compressive force from the prestressing tendons, it slowly deforms and shortens over months and years, beyond its init....