What is the chemical reaction between cement and water that results in hardened cement called?

The chemical reaction between cement and water that leads to the formation of hardened cement is termed hydration. During hydration, water molecules interact with the compounds in cement, primarily tricalcium silicate and dicalcium silicate, resulting in a series of chemical reactions that produce calcium silicate hydrate and calcium hydroxide. This process is crucial because it not only strengthens the cement but also defines the durability and overall performance of concrete.

Curing, while important for maintaining moisture in the concrete after placement to ensure proper hydration, is not the reaction itself but rather a process to support it. Setting refers to the initial phase when the cement begins to harden, marking the transition from a plastic to a solid state, but it does not encompass the entire chemical process involved in hydration. Mixing is simply the process of combining cement, water, and aggregates before the hydration takes place. Therefore, hydration specifically captures the essence of the chemical transformation that leads to the hardening of the cement.