What is the purpose of cover blocks or spacers in rebar placement?

• A. Increase strength
• B. Facilitate curing
• C. Maintain concrete cover and spacing
• D. Reduce steel weight

Answer: (C)

Maintaining proper placement of rebar inside concrete is the key idea. Cover blocks and spacers hold the bars at the exact distance from forms and from each other so the concrete can envelope the reinforcement by the required amount. That concrete cover protects the steel from corrosion and fire and helps the bond between steel and concrete develop as designed. Spacers also keep uniform gaps between bars and other embedded items, aiding concrete flow and consolidation and preventing bars from shifting during pouring and vibration. So the purpose is to ensure the required cover and spacing for durability and proper structural performance.