Pore-scale Modelling of Hygric Properties of Hydrophobised Building Materials

More and more frequently, the application of a water repellent (or hydrophobic) agent is considered to be an efficient way of protecting the facade of a building from the absorption of wind-driven rain and the corresponding moisture problems. To properly evaluate the effect of water repellent agents, hygrothermal simulations of the hydrophobised facade are essential. Up until now, the hygric properties of hydrophobised materials, used as input in these simulations, are determined experimentally. However, this process is lengthy, imprecise and/or impossible with the existing methods. A pore-scale model, capable of simulating the hygric properties of hydrophobised materials, provides a way to overcome these difficulties.
This project aims at developing such a pore-scale model, which is able to determine the hygric properties of hydrophobised materials by simulating the moisture storage and transport processes in the individual pores of the pore network. To this aim, the impact of the hydrophobic agent on the moisture behaviour has to be investigated inside the pores penetrated by the water repellent agent. Once the pore-scale model is developed, its outcome is subsequently validated using experimentally determined hygric properties of the hydrophobised materials. Finally, the application potential of the pore-scale model is illustrated by performing hygrothermal simulations of hydrophobised built structures using the simulated hygric properties as input.