In non-freeze environments, what is a possible effect of using air-entraining admixtures on concrete strength?

• A. They greatly increase early strength.
• B. They can reduce strength slightly and may be unnecessary in non-freeze areas.
• C. They always increase strength.
• D. They have no effect on strength.

Answer: (B)

Air-entraining admixtures introduce tiny, well-dispersed air voids in concrete to improve durability in freezing conditions. In environments that aren’t exposed to freezing, that extra air void space isn’t needed and simply replaces some solid cement paste, which can cause a slight reduction in compressive strength. So in non-freeze environments, these admixtures may be unnecessary and can slightly lower strength. The other statements don’t fit because air voids don’t typically boost strength, and they do have an effect on strength, even if small.