The use of the hot-ball method for observing the transport of moisture in porous stones

Abstract

The effect of moisture on materials leads to changes in their physical and chemical properties. Materials with different porosities are saturated by various mechanisms. This paper is focused on water transport or diffusion in various porous structures. The Hot-Ball Method is used for determining the water content in certain parts of a specimen. The process of water transport or water diffusion is closely related to a porous structure. Porosity affects the transport properties of a material; therefore, knowledge of the mechanisms distributing the water in materials with different porosities is very important. The measurements were carried out by thermal conductivity sensors (hot-ball sensor) located in different positions along the path of the water’s movement. The principle of the hot-ball sensor (thermal conductivity sensor) is based on the Hot-Ball Method for measuring thermal conductivity. The local moisture content and local temperature of a porous stone is inspected using the Hot-Ball Method, where the measured values of the thermal conductivity are correlated with the water content. The experimental set up for the investigation of the water diffusion in stones is described.