Freezing and melting of water in porous geomaterials studied by magnetic resonance

Abstract

We intend to study mechanical effects of freezing and thawing on bulky samples of concrete by nuclear resonance high resolution spectroscopy and imaging (MRI). Variously functionalised three dimensional images of liquid water in the porous media can be obtained by MRI. NMR spectroscopy, on the other hand, can be used to directly measure the total quantity of liquid water as a function of temperature. Moreover, measurements of magnetic spin relaxation rates and diffusion can provide information about distribution of pore sizes (see the figure below) and their connectivity as well as the flow of water through porous media. Knowledge of all these properties is required to fully understand behaviour of porous materials under freezing and thawing.