What does the term ‘hydraulic cement’ refer to?

The term ‘hydraulic cement’ specifically refers to cement that sets and hardens through a chemical reaction with water, making option B the correct choice. This process occurs even in the presence of water, which distinguishes hydraulic cements from non-hydraulic cements that require air to harden.

Hydraulic cement reacts chemically with water to form compounds that eventually lead to the formation of a solid structure, providing strength and stability to various construction materials. This capability allows for use in a wide range of environmental conditions, including underwater applications or in damp environments, making hydraulic cement a versatile choice in construction and civil engineering projects.

The other options mention different characteristics that do not accurately define hydraulic cement. For example, cement that sets and hardens with exposure to air is indicative of non-hydraulic type. Similarly, the mention of additives concerns modifications to cement composition rather than defining the fundamental nature of hydraulic cement. Lastly, while some hydraulic cement products may be used underwater, they are not exclusively limited to that application, further separating them from the description in the incorrect option.