Moisture transport in concrete cover under drying-wetting cycles: Theory, experiment and modeling

The moisture transport processes in concrete cover under drying-wetting actions through modeling and experiments was investigated. The moisture transport processes during drying and wetting in concrete cover were analyzed, and the main mechanism leading to different moisture transport rates for drying and wetting was indicated. Based on the analysis, a diffusion-type model was proposed for the global moisture transport process under drying-wetting actions. The different diffusivities were assigned to drying and wetting phases. The drying and wetting tests on concrete specimens were performed and the basic moisture transport parameters were obtained. The evolution of internal relative humidity was recorded for concrete specimens under drying-wetting cycles with different schemes. The internal humidity evolution of concrete specimens was simulated by the proposed model at various transport parameters. The simulated results were consistent with the experimental data, indicating that the proposed model could be used to predict the moisture transport processes in concrete cover under dry-ing-wetting actions.