Uniform Model for Moisture Transport in Porous Materials and Its Application to Concrete at Selected Chinese Regions

Abstract

The present study investigates the mechanisms of moisture transport in porous materials. For partially saturated porous materials, moisture transport relies on both the Darcian flow by capillary pressure gradient and the Fickian flow by gas concentration gradient. Taking into account the capillary curves that are associated intimately with the pore structure and play crucial roles on both drying and wetting processes, a uniform model that only depends on one variable, the saturation degree, is established. The isothermal adsorption/desorption method and the Kelvin equation are used to evaluate the capillary curve that obeys the van Genuchten form equation. The established model is applied to characterize the moisture distribution in four (near) coastal regions of China (Guangzhou, Hangzhou, Jinan, and Shenyan). Wetting time is shown to be a dominant factor influencing the stable saturation degree and the influence depth.