Moisture transport and fixation in porous materials at high moisture levels
type: CreativeWork
description: The work presented in this thesis focuses on developing methods of measuring moisture properties at high moisture levels. Paper I deal with a new method of measuring moisture diffusivity at high moisture levels. Papers II to IV present methods of measuring moisture storage capacity as well as results from such measurements. Paper V evaluates the use of thermal imaging to measure transient moisture profiles. Paper VI shows how the measured moisture properties can be used in calculations The contents of the six papers are as follows: This paper presents measured moisture diffusivities for several different porous building materials. The diffusivities were calculated from the relation between the water sorption coefficients and the initial water content. The method is based on Boltzmann transformation. Knowledge of moisture storage capacity over the hygroscopic range is essential when calculating the moisture content. Generally storage capacity is represented by water retention curves, in which suction is plotted against moisture content. The pressure plate and pressure membrane technique is often used to measure water retention curves. There are, however, various ways of carrying out such measurements. This paper compares two different methods of presaturating the specimens before testing, namely capillary and vacuum saturation. It also examines the effect of different beddings between the specimen and the ceramic plate. Sorption properties, i.e. information about how much water a porous material holds in different environments, are of interest in many applications. This paper reports on the use of four different methods to measure the sorption isotherm of sandstone. The first method involved equilibrating samples over saturated salt solutions. The second involved weighing small samples in a sorption balance as they were exposed to different relative humidity. The third method was the pressure membrane and pressure plate technique. In the fourth method a newly develop…
abstract: The work presented in this thesis focuses on developing methods of measuring moisture properties at high moisture levels. Paper I deal with a new method of measuring moisture diffusivity at high moisture levels. Papers II to IV present methods of measuring moisture storage capacity as well as results from such measurements. Paper V evaluates the use of thermal imaging to measure transient moisture profiles. Paper VI shows how the measured moisture properties can be used in calculations The contents of the six papers are as follows: This paper presents measured moisture diffusivities for several different porous building materials. The diffusivities were calculated from the relation between the water sorption coefficients and the initial water content. The method is based on Boltzmann transformation. Knowledge of moisture storage capacity over the hygroscopic range is essential when calculating the moisture content. Generally storage capacity is represented by water retention curves, in which suction is plotted against moisture content. The pressure plate and pressure membrane technique is often used to measure water retention curves. There are, however, various ways of carrying out such measurements. This paper compares two different methods of presaturating the specimens before testing, namely capillary and vacuum saturation. It also examines the effect of different beddings between the specimen and the ceramic plate. Sorption properties, i.e. information about how much water a porous material holds in different environments, are of interest in many applications. This paper reports on the use of four different methods to measure the sorption isotherm of sandstone. The first method involved equilibrating samples over saturated salt solutions. The second involved weighing small samples in a sorption balance as they were exposed to different relative humidity. The third method was the pressure membrane and pressure plate technique. In the fourth method a newly develop…
author: Janz, Mårten
language: eng
keywords: Materials Engineering, building construction, water retention curve, diffusivity, suction, Moisture transport, moisture fixation, absorption, capillary transport, byggnadsteknik
identifier: other:ISRN: LUTVDG/TVBM--00/1018--SE(1-162)
date published: 2000
date modified: 2026-07-24T03:00:02Z
provider: University of Lund
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Division of Building Materials, LTH, Lund University