What is the main advantage of using a hydraulic cement like Portland cement?

The main advantage of using a hydraulic cement, such as Portland cement, is that it sets and hardens even under water. This property is particularly beneficial in construction and rescue operations where conditions may be wet or submerged, allowing for structural integrity in situations where traditional cement might fail due to lack of proper curing conditions. Hydraulic cements can react chemically with water to form strong bonds, making them indispensable for applications like foundations, repairs, and structural supports in challenging environments.

While some options may present valid points about other types of cement or economic considerations, they do not highlight the unique and critical capability of hydraulic cement to perform effectively in adverse conditions, which is a fundamental aspect of its usage in construction and rescue operations.