Calcium ions (Ca 2+) play a pivotal role in the chemistry of cement and are fundamental to the process of hydration, which is crucial for the setting and hardening of concrete. These ions are predominantly derived from calcium oxide (CaO) present in the cement clinker and react with other components, such as silicates and aluminates, to form calcium silicate hydrate (C-S-H) and calcium aluminate hydrate phases. These hydration products are responsible for the development of strength and durability in concrete. Understanding the behavior of Ca 2+ ions is especially important in severe environmental conditions where the integrity and longevity of concrete structures are challenged by factors such as chemical attack, freeze-thaw cycles, and corrosion.