Cover Blocks are essentially spacer that lifts the rebar matrix off the
ground/floor to allow concrete to flow beneath rebar.

a) It protects the Reinforcement from Environment exposure or Corrosion.
b) Maintain a specific distance between the steel bars and the shuttering.
c) Give reinforcing bars sufficient embedding to enable them to be stressed without slipping.

Sizes of cover blocks of each structural element is based on the environmental exposure condition i.e. Durability Requirement & to meet Specified period of Fire resistance.

IS-456-2000-Plain & Reinforced Concrete- Code of Practice.

Table 16 Nominal Cover to meet Durability Requirement.

Table 16A Nominal Cover to meet Specified Period of Fire Resistance.

No.

Yes.

• BS-7973-1:2001-Spacers and Chairs for Steel Reinforcement and their
  Specifications – Part-I-Product Performance Requirement.

• BS-7973-2:2001-Spacers and Chairs for Steel Reinforcement and their
  Specifications – Part-II-Fixing and Application of Spacers & Chairs and tying of Reinforcement.

No.

In accordance with BS 8110-1 concrete spacers shall not be made on the construction site.

M50.

Concrete Cover Blocks are tested as per BS7973-1:2001.

No. Both are the same.

Spacing of Bar Should be 50 times Bar Diameter of Slab but not exceeding 1000mm.

Spacer blocks are placed in the Ring of Bar. Maximum spacing is 1000 mm c/c. Number of Cover blocks depends on the size of Beam.

The cover Block should be placed at the Bottom, Mid Span & Top of Each Lift. The number of Cover blocks depends on the Sizes of the Columns.