Hydroxide (OH −) ions are a fundamental component in the chemistry of cement hydration, playing a crucial role in setting and hardening processes. Originating from the dissociation of water and the hydration reactions of Portland cement, OH − ions help form calcium hydroxide, a byproduct that significantly influences the pH levels and durability of concrete. Understanding the role of hydroxide ions is essential, especially under severe environmental conditions that can alter their concentration and impact on concrete properties.