Electrochemistry in the context of cement and concrete refers to the chemical reactions that involve electron transfers, typically occurring in the presence of water and electrolytes. These reactions are fundamental in the processes of corrosion, degradation, and the longevity of concrete structures, particularly those containing metallic reinforcements. Electrochemical processes can either be naturally occurring or induced through technological applications, such as electrochemical chloride extraction and realkalization, which are used to extend the life of concrete infrastructures. Understanding these processes provides critical insights into the preventive measures and remedial actions necessary for maintaining the structural integrity of concrete in aggressive environments.