Difference between Reinforced concrete and Prestressed concrete

Both the reinforced concrete and prestressed concrete structures employ two materials, that is, concrete and steel. Besides these two materials, there is nothing common between them and their structural behavior is quite different.

RC structures

Steel is an internal part and resists the force of tension that concrete cannot resist. The tension force develops in steel when concrete begins to crack and the strains of concrete are transferred to steel through bond. The stress in steel should be limited in order to control cracking in reinforced concrete. In fact, steel acts as a tension flange of a beam. Steel plays a passive role in RCC.

Prestressed concrete

Steel is primarily a means of including a force of prestressing that is applied at the ends of a beam. If this force of prestressing could be induced by some other means then there is no need of steel. There is no necessity for a bond between steel and concrete and the stress in steel does not depend on the strain in concrete. Practically no variation in the stress in steel along the length of a beam. There is no need to limit the stresses in steel in order to control the cracking of concrete. In fact, steel does not act as a tension flange of a beam. Steel plays an active role in RCC.

Advantages of prestressed concrete

• The cross-section is more efficiently used in fully prestressed concrete.
• Dead loads are reduced considerably.
• Improved shear resistance, due to the effect of compressive prestressed, which reduces the principal tensile stress.
• More resistance for impact and vibration.
• Prestressed concrete is more predictable than RCC.
• Prestressed concrete has more fatigue resistance.
• It is more effective for water retaining structures.
• Deflections are less in prestressed structures and hence stiffer.

Check this post to read more about prestressed concrete.