Ion transportation properties of cement-based material under standard curing and steam curing

Abstract

In coastal and saline environments, the infiltration of chloride and sulfate ions into cementitious materials can result in erosion and deterioration. This research focuses on the impact of temperature-related curing methods on the ion transport properties and microstructure of these materials. The results show the curing method does not alter the hydration products of cementitious materials. High-temperature curing reduces the content of ettringite, resulting in decreased Friedel's salt and gypsum after chloride ion corrosion. Meanwhile, high-temperature curing reduces the content of calcium hydroxide (Ca(OH)2) and silicon dioxide (SiO2), decreasing the content of gypsum after sulfate ion erosion. This indicates that high-temperature curing reduces the binding capacity of both chloride ions and sulfate ions. High-temperature steam curing also deteriorates the pore structure compared to standard curing. As a result, the resistance of concrete to ion corrosion is reduced under high-temperature steam curing. In addition, the surface ion concentration and binding capacity of chloride ions and sulfate ions both increase with the duration of erosion. At the same erosion age, the binding capacity of sulfate ions is significantly higher than that of chloride ions. This research provides new insights into the transport characteristics of eroding ions under high-temperature steam curing.