Benefits of concrete covers blocks in RCC work

This construction video tutorial will guide you to make concrete cover block or rebar spacer at a reasonable cost.

A rebar spacer belongs to a object that fastens the reinforcing steel or "rebar" in reinforced concrete structures since the rebar is amassed in place before the pouring of final concrete. The spacers are remained in place for the pour to set the reinforcing in place, and turn into a permanent part of the structure.

When RCC work is going on, implanting steel in concrete (called as cover) is a vital process for resisting rebar from decaying as well as arranging fire protection to the rebar. If the proposed cover is not arranged, the rebar will start to decay in due course of time and will lead to collapsing of the structure beforehand. So, cover blocks can extend the life of the structure considerably without incurring so much expenses.

The exact amount of cover is set by the application and the environment (e.g., is the RCC under water, etc.)

In India, following are considered as the standard size for the covers :

Slab : 20 mm
Beam : 25 mm
Column : 40 mm
Foundation : 50 mm

Concrete covers ensure the accurate position of steel, thus allowing in the practical application of the theoretical specifications of concrete construction. The cover of the steel concerning a specific construction component (for instance in a concrete slab or a beam) should be usually constant inside the element.

The application of covers can be beneficial to the areas where high earthquake activity along with corrosive environment (like proximity to salt water of sea) occurs.

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Published By
Rajib Dey
www.constructioncost.co

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Different types of clear cover in reinforcement concrete

This construction video tutorial provides brief instructions on how to arrange clear cover in different areas in proper quantities in reinforcement concrete. It is dependent on the exposure condition and fire resistance.

Clear Cover stands for the minimum distance among the surface of embedded reinforcement and the exterior surface of the concrete (ACI 130). The depth of clear cover is calculated with a cover meter.

Given below the details of clear cover :-

For water retaining structures – The clear cover should vary from 20 mm to 30 mm
For flat slab – The clear cover should be 20 mm
For slab – The clear cover will be 15 mm
For column – The clear cover should have been 40 mm
For strap beam – The clear cover should be 50 mm

For raft foundation at bottom – The clear cover should be 75 mm
For shear wall – The clear cover should be 25 mm
For footing – The clear cover should be 50 mm
For staircase – The clear cover should be 15 mm

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Published By
Rajib Dey
www.constructioncost.co

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Some useful construction tips to provide clear cover for reinforced concrete structure

This construction video tutorial will provide detailed guidelines on how to provide perfect clear cover in reinforcement concrete structure.

With the intension of safeguarding the reinforcement from corrosion as well as arranging fire resistance to bars implanted in concrete, clear cover is set for Reinforced Concrete Structures.

Clear cover stands for the distance among C.G of reinforcement bars and bottom most point of concrete.

The thickness of cover is dependent on ecological conditions and nature of structural member.

The depth of concrete cover is calculated by applying a cover meter.

The clear cover that should be provided is determined by Indian Standards. IS 456:2000.

Watch following youtube video to learn the complete process :-

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Published By
Rajib Dey
www.constructioncost.co

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Specification Of Concrete Cover For Concrete Slab Design

Concrete cover for reinforcement is essential for safeguarding the rebar against erosion as well as fire. The depth of the cover is based on ecological conditions and type of structural member. The slightest thickness of reinforcement cover is specified in the drawings, or achieved from the related code of practice. The specifications for reinforcement cover for various structural members in diverse conditions are explained below :-

a) To each end of reinforcing bar, not below 25 mm or below twice the diameter of the bar.

b) In case of a longitudinal reinforcing bar in a column, not under 40 mm not less than the diameter of such bar. For columns of least dimension of 20 cm or below, whose reinforcing bards should not surpass 12 mm, a cover of 25 mm should be applied.

c) For longitudinal reinforcing bars in a beam, not under 30 mm or below the diameter of the bar.

d) For tensile, compressive shear or other reinforcements in a slab or wall not below 15 mm, not less than the diameter of such bar.

e) For any other reinforcement not below 15 mm, not less than the diameter of such bar.

f) For footings and other major structural members in which the concrete is placed directly alongside the ground, cover to the bottom reinforcement must be 75 mm. If concrete is discharged on a layer of thin concrete, the bottom cover is curtailed to 50 mm.

g) For concrete surfaces uncovered to the weather or the ground once forms are separated - like retaining walls, grade beams, footing sides and top etc. below 50 mm.

h) Expanded cover thickness is offered as specified on the drawings, for surfaces uncovered to the action of injurious chemicals (or uncovered to earth polluted by such chemicals), acid, alkali, saline atmosphere, sulphorone, smoke etc.

For more information, visit this link.

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Published By

Rajib Dey

www.constructioncost.co

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