Which type of Portland cement is known for setting the quickest and hardest?

Type III Portland cement is known for its rapid setting and high early strength, making it ideal for construction projects that require fast setting times. This type of cement typically contains higher amounts of tricalcium silicate, which contributes to quicker hydration and strength development. It is particularly useful in situations where concrete needs to achieve strength rapidly, such as in cold weather constructions or when time constraints are critical.

In contrast, other types of Portland cement, such as Type I, Type II, and Type IV, provide different performance characteristics. Type I offers a general-purpose use, Type II is designed for moderate sulfate resistance, and Type IV is known for low heat of hydration, making it suitable for massive structures. However, none of these types match the quick setting and hardening properties of Type III, which is specifically formulated for applications where speed and strength are paramount.