Volume: 2, 2023
2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: T038
DOI: https://doi.org/10.24326/ICDSUPL2.T038
Published online: 19 April 2023
ICDSUPL, 2, T038 (2023)
Monitoring of water flow in porous materials using TDR
Dominika Mikušová1*
1 Department of Water Supply and Wastewater Disposal, Faculty of Environmental Engineering, Lublin University of Technology, ul. Nadbystrzycka 40B, 20-618, Lublin, Poland
* Corresponding author: d583@pollub.edu.pl
Abstract
Moisture present in building porous materials affects their properties such as thermal conductivity and mechanical strength. Mechanical strength decreases due to degradation of material by moisture (crystallization of salts, freezing of water, dissolution of materials). Increased thermal conductivity is associated with higher energy consumption for heating, which has a negative ecological and economic impact. Additionally moisture present in building barriers causes many health and hygiene risks. Therefore, there is a demand for a deeper understanding of hygrothermal properties. The main prerequisite for determining properties such as hydraulic permeability, dispersion coefficients, thermal conductivity and heat transfer coefficients is to know the basic processes that occur in unsaturated media, including water flow; convection and dispersion/diffusion of heat in water; and heat conduction in the matrix. The flow of water in materials is theoretically described using the Richards equation. In practice, it is possible to monitor the flow of water into materials using Time Domain Reflectometry (TDR). TDR is an indirect method for determining humidity by measuring dielectric permittivity. The dielectric permittivity value of water equals 80 which differ greatly from the permittivity value of materials commonly used in construction (1-15) and air (1). This makes it possible to determine the moisture content in materials by the permittivity measurement and the ability of the TDR technique to automate the measurement gives this technique high potential for monitoring of isotheral moisture flow in porous building materials. For the experiment 8 channel TDR multimeter (ETest, Lublin) was applied together with the FP/mts probes that enabled constant monitoring of water content changes in the tested material samples. With the experiment a series of apparent permittivity values were read that were recalculated into moisture and material ability for isotheral water flow was determined. By using the TDR technique, it is possible to monitor the isotheral moisture flow in porous building materials.
How to cite
D. Mikušová, 2023. Monitoring of water flow in porous materials using TDR. In: 2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL2.T038