Portland cement, a fundamental ingredient in concrete, is manufactured by heating limestone and clay minerals in a kiln to form clinker, which is then ground with gypsum to produce the final product. This hydraulic cement is characterized by its ability to set and harden through a chemical reaction with water, known as hydration. This process forms a stone-like substance, making Portland cement essential for building durable structures. Under severe environmental conditions, such as exposure to high sulfates, freeze-thaw cycles, and corrosive environments, the hydration mechanism and the resultant microstructure of the cement can be significantly altered. These changes affect both the physical and chemical properties of the cement, impacting its durability and functional lifespan.