Energy-filtered transmission electron microscopy (EFTEM) is an advanced analytical technique that enhances the capabilities of conventional transmission electron microscopy by incorporating an energy filter to select electrons of specific energies. This method allows for detailed imaging and analysis of the elemental and chemical composition at the nanoscale. In the context of cement and concrete, EFTEM is particularly valuable for investigating the microstructural changes, hydration products, and failure mechanisms that occur at these extremely small scales. Understanding these aspects is crucial for improving the durability and performance of concrete structures under severe environmental conditions, such as exposure to corrosive agents, freeze-thaw cycles, and high temperatures.