In cold weather, using a rich mix serves to

• A. Increase early strength of concrete in cold weather.
• B. Increase overall strength at later ages.
• C. Decrease heat of hydration.
• D. Increase curing time.

Answer: (A)

In cold weather, hydration proceeds slowly, so getting early strength quickly is crucial to prevent freezing and to enable safe handling and form removal. A rich mix—having more cement content—produces more heat of hydration and provides more binding material early in the curing process. That extra heat helps raise the concrete temperature and accelerates early strength gain, which is why this approach is used in cold conditions.

The other ideas don’t match the practical goal here: more cement doesn’t decrease the heat generated; it increases it. It isn’t primarily about extending curing time, and while long-term strength can be influenced by mix, the key benefit in cold weather is faster early strength development.