Why are rebar chairs and spacers important during concrete placement?

• A. They accelerate curing
• B. They are decorative only
• C. They hold bars in proper position and maintain required cover and spacing
• D. They increase corrosion rate

Answer: (C)

Keeping reinforcing bars in the right position during concrete placement is essential for the member to behave as designed. Rebar chairs and spacers hold each bar at the correct height and maintain the required clear distance between bars. This ensures the concrete cover around the steel is sufficient, which protects against moisture and aggressive chemicals that can cause corrosion and reduces fire exposure risks. Proper placement also lets concrete flow and be properly vibrated around the bars, improving compaction, bond, and overall strength. In short, these devices ensure the bars stay where they belong, maintain the needed spacing and cover, and contribute to long-term durability. They are not used to speed up curing, they aren’t decorative, and when used correctly they help reduce corrosion risks rather than increase them.