This section will define the hydration process in the context of cement chemistry. It will describe how water interacts with cement particles to initiate chemical reactions that lead to the setting and hardening of concrete. The key compounds involved, such as tricalcium silicate (C3S) and dicalcium silicate (C2S), will be discussed, along with their respective roles in the formation of calcium silicate hydrate (CSH) and calcium hydroxide, which are crucial for the development of strength and durability.