Concrete Cover for Reinforcements – Its Types and Importance

Concrete cover is much necessary to protect the steel against corrosion (rusting) and to provide resistance against fire. Concrete cover can be made with either Plastic or Mortal of at least 1:3 mix ratio, this will make it strong and should be immersed in water for 28 days to get the maximum strength. All structural parts that required reinforced concrete were checked to ensure adequate concrete cover also cover block are provided to the bottom and sides of the reinforcement. Main bars of the columns were adjusted to ensure the covering requirements before concreting. Stools of correct height were used to maintain the require gap between top and bottom reinforcement nets and cover blocks were also provided to bottom reinforcement.

CONCRETE COVER SIZES FOR REINFORCEMENTS ON SITE

FOOTINGS – 50 mm

RAFT FOUNDATION (TOP) – 50 mm

RAFT FOUNDATION (BOTTOM/SIDES) – 75 mm

STRAP BEAM – 50 mm

GRADE SLAB – 20 mm

COLUMN – 40 mm

SHEAR WALL – 25 mm

BEAMS – 25 mm

SLABS – 15 mm

FLAT SLAB – 20 mm

STAIRCASE – 15 mm

RETAINING WALL – 20 / 25 mm on earth

WATER RETAINING STRUCTURES – 20/30 mm

DIFFERENT TYPES OF CONCRETE COVER FOR REINFORCEMENT

[1] PLASTIC SPACER

This technique is assumed to be the most practical one compare with other methods. Not only does the cost of plastic pieces is low but also it executes the cover thickness accurately since it can bear great loads due to its high strength. That is why the application of these plastics has recently been increased.

Various types of plastics are produced based on the diameter and forms of the bar, thickness of concrete cover, and the location of steel bars.

[2] CONCRETE CUBOID ( BISCUITS )

This technique is one of the most well known practical methods used to execute concrete cover. Commonly, the dimension of biscuit is 50x100mm and its thickness varies based on the concrete cover thickness requirement.

IMPORTANCE OF CONCRETE COVER

[1] Concrete cover is much necessary to protect the steel against corrosion (rusting).

[2] Concrete cover provide resistance against Fire.

[3] Concrete cover prevent deterioration of reinforcement steel bars.

[4] Concrete cover help in maintain the cover between shuttering boards and the mesh of the reinforcement.

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