A superplasticizer admixture used to increase the workability of concrete has a short-lived time window of how many minutes?

A superplasticizer admixture used to increase the workability of concrete has a short-lived time window of how many minutes?

• A. 15 to 30 minutes
• B. 30 to 45 minutes
• C. 30 to 60 minutes
• D. 45 to 90 minutes

Answer: (C)

Ultra-smooth, high-workability concrete from a superplasticizer is temporary—the dispersion it provides loosens as cement hydrates. In practice, you have a relatively short window to place and finish the concrete, typically about 30 to 60 minutes after mixing. This range covers common field conditions: at higher temperatures the window shrinks toward the 30-minute end, while cooler conditions or certain retarder adjustments can push it toward the 60-minute mark. The other options are outside what’s normally expected for standard superplasticizers, so 30 to 60 minutes is the best general match.

Ultra-smooth, high-workability concrete from a superplasticizer is temporary—the dispersion it provides loosens as cement hydrates. In practice, you have a relatively short window to place and finish the concrete, typically about 30 to 60 minutes after mixing. This range covers common field conditions: at higher temperatures the window shrinks toward the 30-minute end, while cooler conditions or certain retarder adjustments can push it toward the 60-minute mark. The other options are outside what’s normally expected for standard superplasticizers, so 30 to 60 minutes is the best general match.