Quantitative X-ray diffraction (XRD) is a powerful analytical technique used to determine the phase composition of crystalline materials, such as those found in cement and concrete. By measuring the intensity and position of diffracted beams, XRD can identify the crystalline phases present in the material and quantify their proportions, providing vital data for understanding the chemistry and mineralogy of cementitious materials. This technique is particularly useful under severe environmental conditions, such as high temperatures, corrosive environments, or high pressures, where the durability and integrity of materials are critically tested. XRD helps in monitoring changes in the crystalline structure of cement, aiding in the development of formulations that can withstand these harsh conditions.