Which type of Portland cement should be used in hot conditions or if extra working time is required?

The appropriate choice for use in hot conditions or when extended working time is necessary is Type IV Portland cement. This type of cement is specifically designed to produce low heat of hydration, making it suitable for large-scale construction projects where managing temperature fluctuations is crucial, such as when concrete is placed in high ambient temperatures.

Using Type IV cement helps mitigate the risk of thermal cracking that can occur when concrete hydration generates excessive internal heat, thus allowing for a longer time to work with the mixture before it sets. Its slower rate of strength development compared to other types means that it remains workable for a more extended period, allowing for careful placement and finishing.

Type III is intended for quick setting and higher early strength, making it unsuitable for hot weather needs where longer workability is preferred. Type I is a general-purpose cement without the specific modifications for handling heat. Type V is designed to resist sulfate attack and does not address the concerns associated with working time or hot weather conditions. Therefore, Type IV is the optimum choice in these scenarios.