Which type of Portland cement is used where an early strength gain is important?

Type III Portland cement is specifically designed to achieve high strength at an accelerated rate compared to other types. This is particularly beneficial in situations where early strength is critical, such as in cold weather concreting, precast concrete products, and rapid repair work. The formulation of Type III cement allows for quicker hydration and faster development of compressive strength, making it ideal for applications that require the structure to be load-bearing sooner than the typical curing process would allow.

In contrast, Type I is a general-purpose cement with a standard setting time, Type II has a lower heat of hydration suitable for massive structures, and Type IV is formulated to minimize heat generation and is used in large constructions where reducing temperature rise is essential. None of these alternatives provide the same early strength capabilities as Type III, which is why Type III is the best choice in scenarios where an early strength gain is paramount.