What is the role of cement in concrete?

Cement plays a crucial role in concrete primarily as a bonding agent. When mixed with water, cement undergoes a chemical reaction known as hydration, which allows it to bind together aggregates such as sand and gravel to form a solid mass. This bonding capability is essential because it gives concrete its strength and durability, enabling it to withstand tensile and compressive forces.

The bond that cement creates among the various components of concrete ensures that the mixture maintains its integrity over time, preventing separation of the materials under load. Additionally, this bonding process is what allows concrete to achieve its strength characteristics as it cures and hardens. The other options, while they may describe some qualities of concrete or its uses, do not capture the fundamental role of cement as effectively as its function as a bonding agent does.