Which of the following is NOT a characteristic feature of ACI recommendations for winter concrete?

The recommendation for winter concrete practices emphasizes the importance of monitoring temperature to ensure proper curing and setting conditions. During cold weather, concrete must be protected from freezing and must reach its intended strength. This involves closely monitoring the temperature of both the concrete and the ambient environment to ensure that the concrete cures adequately.

A lack of temperature monitoring could lead to improper setting or even freezing of the concrete, which could compromise its strength and durability. Therefore, this characteristic of minimal monitoring is not in line with ACI guidelines, which advocate for vigilant temperature tracking during winter placement.

The other choices reflect practices recommended by ACI for effectively managing concrete in cold weather. Low slump helps in maintaining workability without excessive water that could impair strength. Increased insulation for corners aids in protecting vulnerable areas of the pour from temperature drops. Maintaining surface temperatures is crucial to ensure that the concrete does not freeze, allowing it to cure properly.