Reinforced concrete components, e.g. ceilings, can be slackened or prestressed. For installation on site, slack reinforcement is mainly used, with the reinforcing steel being inserted "limply" into the formwork. Only after the concrete has hardened, when the component is loaded after stripping, does the steel take over the tensile force.
Prestressed reinforcement is distinguished by a planned pre-tensioning or pre-stretching of the steel members in the unloaded state. The concrete is "compressed" in this way. In the loaded state, the longitudinal clamping force leads to a reduction in the compressive load in the concrete. Tensile forces acting on the concrete do not occur or are absorbed by the prestressing steel.
Source: bauwion
