The American Concrete Institute (ACI) has released a paper called Similarities in Accelerated Chloride Ion Transport Tests for Concrete in Tidal Zones.
For the study, written by Qing-Zhang Zhang, Xiang-Lin Gu, Zhi-Lu Jiang, and Wei-Ping Zhang, the model for chloride transport in concrete was established by considering the effects of diffusion and capillary suction. Chloride penetration tests verified it under cyclic wetting and drying conditions.
ACI says: “The developed model was used to analyse similarities under different environmental conditions for accelerated tests. The results showed that the influence of external chloride concentration on chloride penetration was smaller with a larger depth.”
The investigation found when the ambient relative humidity (RH) decreased, the penetration rate increased when RH was larger than 70%. However, the penetration rate decreased when the RH was smaller than 70%.
According to ACI: “The results also indicated that when the wetting-to-drying time ratio in a cycle increased, the penetration rate increased first and then decreased after a critical ratio. When the cycle period decreased, the penetration rate first increased and then decreased during a small time period.”
