**3. Cement, mortar, and concrete**

The terms cement, concrete, and mortar are often used synonymously even though they are not. Cement, concrete, and mortar are actually three distinct materials [10].

**Cement:** As mentioned previously, cement turns into a gel-like material when mixed with water, having glue characteristics. Cement is never utilized alone, but it is an essential component of both concrete and mortar, binding their main components together.

**Mortar:** Mortar is a mixture of cement and fine aggregates (usually sand or other similar components) combined with water. It has the proper consistency to provide a thick, uniform lining that adheres securely to surfaces to bind materials together, for example, bricks, concrete blocks, or stones.

**Concrete:** Like mortar, concrete is composed of cement and fine aggregates mixed with water, but also coarse aggregates like graves, which makes it stronger and more durable.

Concrete has a lower water-to-cement ratio and thinner consistency than mortar, as well as more strength duo to the presence of the large aggregates.

There are three main types of concrete based on density.

**Ordinary concrete:** This is the most often utilized kind of concrete. It is employed in building construction where very high tensile strength is not required. It has moderate density around 2200–2500 kg/m3 .

**Lightweight concrete**: The single most essential characteristic of lightweight concrete is its extremely low heat conductivity. It is used for thermal insulation, construction blocks, and to protect steel buildings. It has low density less than 1900 kg/m3 [11].

**High-density concrete:** This type of concrete is also known as heavy weight concrete. High-density materials are used as fine aggregates, coarse aggregates, or both. It is typically seen in nuclear power reactors and other comparable buildings because it offers excellent protection against all types of radiation. This concrete may have very high density of 3000–4000 kg/m3 [12].
