Untersuchung von Feuchtetransport mittels numerischer Modellierung und Neutronentransmissionsanalyse / Study of Moisture Transport by Numerical Modeling and Neutron Transmission Analysis

Moisture transport in porous building materials is described by a transport model that expresses the action of the several transport mechanisms of liquid water and water vapor in the porous system by a single material specific transfer coefficient. This parameter has to be determined by experimental measurement of moisture distributions inside samples exposed to known initial and boundary conditions. Neutron radiography is employed as experimental method because of its high sensitivity and good spatial resolution. The moisture distribution is determined from the raw data obtained in the measurement by a calculation procedure based on a signal transfer model of the neutron transmission. This approach is illustrated by two examples: the drying of a plain brick sample and the drying of a composite sample consisting of two brick elements separated by a layer of mortar.