Building materials studied by MRI

Salt weathering of porous media is widely recognized as one of the primary causes of irreversible damage to many cultural objects such as wall paintings, sculptures, historic buildings, and other artwork. Moreover, contemporary buildings and civil constructions also suffer from salt-related deterioration processes. In all these cases, moisture transport forms the catalyst for these processes. To obtain information about the mechanisms underlying deterioration processes, one has to study the moisture and ion transport in building materials. Nuclear magnetic resonance (NMR) offers the only technique with the possibility to image simultaneously moisture and ion transport in these materials. Moreover, it can give insight into the transport at various length scales from micro to macro. However, serious complications occur if the materials under investigation contain large amounts of paramagnetic ions, as is the case for many common building materials. These complications for NMR will be discussed both for moisture and ion measurement and some examples of moisture and ion transport will be presented.