04/04/2025
Pre-stressed concrete is a type of concrete in which internal stresses are introduced to counteract the external loads that will be applied during its use. The primary goal of pre-stressing is to improve the concrete’s performance, especially under tension, by preventing cracks and minimizing bending or deformation.
There are two main types of pre-stressed concrete:
1. Pre-tensioned Concrete:
• In this method, steel tendons (wires or cables) are stretched (pre-tensioned) before the concrete is poured. These tendons are anchored to a frame and stretched, and the concrete is then poured around them. Once the concrete hardens, the tendons are released, transferring the stress to the concrete.
• This method is typically used in precast concrete elements, like beams or slabs, that are produced in a factory setting.
2. Post-tensioned Concrete:
• In this approach, tendons are placed in ducts or sleeves within the concrete slab or beam, but they are not pre-stressed during the pouring of concrete. After the concrete has set, the tendons are pulled (tensioned) and anchored at the ends. This creates compressive stresses in the concrete, counteracting the tensile stresses due to external loads.
• This method is often used for cast-in-place concrete, like in foundations, bridges, or large slabs.
