X-ray diffraction (XRD) is a powerful analytical technique widely used in the study of cement and concrete to determine the phase composition and crystallinity of materials. XRD works by directing X-rays toward a material and measuring the intensity and angles of the rays that are scattered by the material’s atomic lattice. This method allows for the identification of crystalline phases present in the cement, such as calcium–silicate–hydrate (C-S-H), ettringite, and calcium hydroxide, among others. Understanding these phases is crucial for assessing the material’s quality, durability, and reaction processes, especially under severe environmental conditions such as extreme temperatures, moisture, and corrosive environments, which can alter the hydration products and overall material behavior (Snellings et al. 2012).