ABSTRACT
The chloride ions within cement-based materials can be separated into two parts: free and bound chloride ions. This chapter discusses the chloride binding of cement-based materials and its effects on chloride transport and microstructure of cement-based materials. The physical and chemical interactions between chloride ions and solid phase in cement-based materials can affect the process of chloride ingress. Chloride concentration is probably one of the most important factors affecting chloride binding. Natural diffusion test and rapid chloride migration test are widely applied in evaluating the chloride penetration resistance of cement-based materials. Knowledge of water distribution of hardened cement pastes is necessary to explain the chemical and physical properties of cement-based materials. Chloride binding is a very complicated process and is affected by many factors, such as chloride concentration, cement composition, hydroxyl concentration, cation of chloride salt, temperature, supplementary cementing materials, carbonation, sulfate ions, and electrical field.
