Moisture Diffusion in Cementitious Materials: Adsorption Isotherm

This article describes an improvement on a previous model proposed by Ba~ant and Najjar, in which moisture diffusivity and moisture capacity are treated as separate parameters. These parameters are evaluated from independent test results, and are shown to depend on the water:cement ratio, curing time, temperature, and cement type. The moisture capacity is obtained as theslope of the adsorption isotherm. A mathematical model is developed and is shown to pre-dict experimental dsorption isotherms of Portland cement paste very well. In the present form, the model is not applicable to hig