Concrete has a high compression strength but relatively low tensile strength. One way to overcome this shortcoming is to apply tensile load on the concrete so that even under maximum load it is still in compression or limited tension. This method is called Prestressed Concrete as the stress is intentionally applied prior to the concrete structure being put into use.
THERE TWO COMMONLY USED WAYS OF PRESTRESSING CONCRETE
In pre-tensioning method, the tendons are placed inside the ducts and then stressed. Concrete is poured and after reaching certain strength tendons are loosened. This method is generally adopted in specialized plants outside the construction site to build precast elements which are then transported to site and assembled.
In post-tensioning method, concrete is poured first and stressing is conducted after the concrete reaches a certain strength. This method is applied on site and upon completion of stressing of tendons, concrete based grout is injected inside the ducts to provide protection against corrosion.
Post-tensioning can be adopted in many different types of structures such as bridges, slabs, silos, etc. This method offers numerous advantages in terms of cost, construction speed, structural performance and material usage.
Intac, with its competitive approach, offers savings on material costs, faster construction and wider spans. Moreover, additional advantages like reduced height and weight of the structure and deflection control also come with post-tensioning.