The influence of dynamic environmental conditions on capillary water uptake of building materials

Water capillary absorption is one of the main water uptake mechanisms in building materials, affecting their overall durability. Thus, the investigation of their capillary rise kinetics can be very useful as regards understanding buildings behavior, contributing to the increase of their durability and their service life. For this reason, a first_order mathematical model was used describing the capillary water uptake under dynamic environmental conditions (different air velocity, air temperature, and relative air humidity) for various natural and artificial building materials. This model successfully fits the experimental data. From the results, it was found that both building materials’ intrinsic characteristics and environmental conditions influence the capillary rise kinetics. In order to assess the validity of the proposed model, a comparison with a similar model was performed. The fitting of the utilized model was more accurate because of the incorporation of the environmental parameters into it. Finally, the proposed model was utilized in order to predict the capillary water uptake under hypothetical extreme weather real-case scenarios. It was found that the proposed model can successfully predict the capillary water uptake under different real-case environmental conditions. The applicability of this semi-empirical model, using parameters with physical meaning, could make it suitable for use in building simulators. This model can contribute to risk assessment tools, dealing with various challenges related to climate change and its effect upon built environment.