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Nov 30, 2018 / By System Admin / in TMT Steel
A cover block is basically a spacer that is used to lift the rebar matrix off the ground so that concrete may flow below the rebar.
In order to prevent corrosion of the rebar, it has to be totally sheathed in concrete. It usually needs about 2 to 3 inches of coverage on all sides. So the cover block lifts the rebar up by about 2 to 3 inches and becomes a permanent and integral part of the poured concrete, make certain that no part of the rebar sags and minimizes that required concrete coverage throughout the pour.
While doing RCC work it is important to embed the steel in the concrete (also known as cover) so that the Rebar doesn't corrode and to provide fire protection to the Rebar. If the cover is not recommended the Rebar will corrode with time and will ultimately result in premature failure of the structure. Thus using cover blocks enhances the life of the structure significantly without adding much to the cost.
As plastic is a different material than concrete and has a different coefficient of thermal expansion than concrete, it does not bond properly with concrete. It is observed that hair cracks develop between plastic and concrete surface, which allow ingress of corrosive gases, which in turn accelerates corrosion.
While concrete spacers are made from high strength concrete, these concrete spacers bond perfectly with the surrounding concrete.
Parameter | PVC/Plastic Spacer | Concrete cover blocks |
---|---|---|
Strength | Cannot be designated | M30 and more |
Wastage | 10% to 15% - minimum | No Damages |
Area Coverage | 150 to 200 Sq. Ft per 100 Nos. | 300 to 400 Sq. Ft per 100 Nos. |
Finishing | NIL | Concrete Finish |
Bondage | No bondage | As good as concrete |
Mix | Plastic Waste | Design Mix |
Concrete Spacers prevent rebars from corrosion, protect them from fire to certain length of time and help to provide proper transfer of stresses from concrete to steel rebars, by helping provide proper cover to rebars.
The right amount of cover is determined by the application and the environment (e.g., is the RCC underwater, etc.)
In normal environments, the following are typical covers recommended.
Application | Cover (In mm) |
---|---|
Slab | 20 mm |
Beam | 25 mm |
Column | 40 mm |
Foundation | 50 mm |
Click here to buy highly reliable and resistant concrete cover block at materialtree.com, we have a different range of concrete cover blocks in various sizes.
Available sizes
-20 mm x 40 mm x 50 mm
-20 mm x 30 mm x 25 mm
Dec 13, 2022 by System Admin
Dec 13, 2022 by System Admin