Building materials characterization with a portable Nuclear-Magnetic-Resonance device

Type: Experimental and modelling-oriented

Language: German or English

Start: from september 2022

Duration: ca. 6 - 12 months

Supervision: Priv.-Doz. Dipl.-Ing. Dr. Michele Bianchi Janetti; Prof. Peter Gamnitzer (Arbeitsbereichs für Festigkeitslehre und Baustatik)

Prerequistes: Building physics and/or heat and mass transfer, interest for experimental work, material characterization and numerical modelling 

Description

The availability of experimental techniques for the reliable assessment of the moisture distribution in porous materials is crucial in many fields of engineering such as concrete technology, soil science and building physics. Nuclear magnetic resonance (NMR) has been shown to be a powerful technique for non-invasive moisture content measurements. While conventional non-movable NMR devices are limited to laboratory applications, single-sided NMR based on open magnets are portable sensors suitable also for in situ measurements. However, the application of such devices to building materials requires further investigation. This Master Thesis aims at performing a step forward on this front. The following tasks are defined:

  1. Familiarization with the theoretical background on nuclear magnetic resonance and its application to porous materials characterization.
  2. Determination of pore size distribution as well as moisture distribution in material samples subject to water uptake and drying.
  3. Comparison with results by different experimental techniques (e.g. gravimetric analysis) and evaluation of the measurements accuracy.
  4. Derivation of the moisture retention curve and moisture diffusivity curve for the application in moisture transfer models.
Drying of a material sample - Measurement of water content via NMR
The figure shows the sensor starting at the lowest position of the scanning range (left). By moving the sensor upwards, the position of the sensitive volume is shifted to profile the water content as a function of the position. Right: exemplary water content profiles in a drying sample.

In case of interest please contact:

Priv.-Doz. Dipl.-Ing. Dr. Michele Bianchi Janetti
Fakultät für technische Wissenschaften, AB Energieeffizientes Bauen
Michele.Janetti@uibk.ac.at

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