What is Prestressed Concrete?

Prestressed concrete (PSC) is the composite of concrete and prestressed high tensile tendons. In PSC, the internal stress has been introduced under controlled circumstances before loading, to improve the shrinkage resistance of concrete and avoid the tensile cracks.

High tensile strength wires are used in prestressed concrete.

Prestressed Concrete

What is Reinforced Cement Concrete?

Reinforced cement concrete is the composite of concrete and ordinary mild steel reinforcement or deformed bars that can resist the different types of load, such as compressive, tensile, and shear force. RCC is having functional resistant capacity against fire.

Reinforced Concrete Beam

Why is Prestressed Concrete Introduced?

In RCC, the concrete takes the compression load, and steel takes the tension load. The section of concrete on the tension side and steel on the compression side becomes ineffective. Though steel on the tension side takes the tensile loads, minor cracks will be introduced on the concrete.

Since prestressing has been applied in PSC, both concrete and steel will be effective in load-carrying capacity. The cracks developed due to tension will also be minimized.

Difference between Reinforced Concrete and Prestressed Concrete

Reinforced Cement Concrete Prestressed Concrete
Fatigue limit is low Fatigue Limit is high. (Fatigue – Number of stress cycles applied to the member below the permissible level without causing deformation.)
Incase of deflection it deforms more compared to PSC Incase of deflection It deforms less (¼ th of RCC Level)
Material cost is low Material cost is high
Mild steel and deformed bars are used High strength tendons are used. Tendons are made from high tensile steels in the form of a single wire or multi-wire strands.
No internal stress is induced in RCC Internal stress has been introduced prior to loading
Tensile cracks will be visible No tensile cracks
The dead load of RCC is high compared to PSC The dead load of PSC is less compared to RCC
No quality control required Requires good quality control and skilled labour
No need for any special techniques It needs a special technique to anchorage the tendons and to apply pressure.
In RCC members, the concrete of the tension area (lower) is ineffective viceversa. All sides of the prestressed concrete are effective in terms of load handling.
Needs shear reinforcement Shear tension is resisted by providing tendons.
No high strength concrete required High strength concrete is needed
RCC is preferred where dead weight is more important than strength PSC is preferred in heavy loads and longer span area
No way of testing the steel Testing of steel can be done before placing them
Steel corrosion is possible in RCC Since concrete cracks are minimized, corrosion of steel is negligible in PSC
Used in building construction Used in railways sleepers, bridges, gravity dams
Less Brittle More brittle

Happy Learning 🙂

Author

Satheesh is a Civil Engineer who has more than 9+ Years of experience in residential construction. He is the author, editor of Civil Planets

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