What type of Portland cement is recommended when moderate heat of hydration is required?

When moderate heat of hydration is required in concrete applications, Type II Portland cement is the recommended choice. This type of cement is specifically designed to produce lower heat during hydration compared to Type I cement, while still achieving adequate strength and durability.

Type II cement contains moderate levels of tricalcium silicate, which reduces the heat of hydration compared to Type I, making it suitable for structures that are prone to thermal cracking due to significant temperature changes during the setting and curing process. Furthermore, it can also provide resistance to moderate sulfate attack, which adds to its applicability in various environments.

Other types of Portland cement serve different purposes; for instance, Type I is a general-purpose cement with a standard heat of hydration, Type III is formulated for rapid strength gain and produces higher heat, and Type IV has very low heat of hydration but is not typically used for moderate conditions due to its slower strength development. Therefore, Type II is the ideal option for scenarios where controlled heat generation is important to maintain structural integrity and prevent damage during curing.