The degree of hydration in cement and concrete refers to the extent to which the cementitious materials have reacted with water. This parameter is critical because it directly influences the material’s properties such as strength, durability, and porosity. Under severe environmental conditions, such as extreme temperatures, high humidity, or exposure to corrosive agents, the degree of hydration can be significantly affected. The hydration process begins when water is added to cement, initiating a series of chemical reactions that transform the dry cement particles into a hardened, cohesive mass. The complete hydration of cement is a theoretical ideal; in practice, the degree of hydration typically ranges between 70% and 90% depending on the mix design, curing conditions, and age of the concrete.