DETERMINATION OF MOISTURE PROFILES IN POROUS BUILDING-MATERIALS BY NMR

Because moisture in porous building materials can give rise to several kinds of damage, a detailed knowledge of the moisture transport is es sential, For such studies it is important to measure dynamic moisture profiles quantitatively. Nuclear Magnetic Resonance (NMR) offers a pow erful technique to measure such profiles in a nondestructive way. Beca use of the large amount of paramagnetic ions present in many of these materials (0.1-5% Fe) standard NMR imaging equipment cannot be used, A NMR apparatus will be described that was especially developed to stud y the moisture transport in porous building materials. At the moment, one-dimensional moisture profiles in samples with a diameter of 20 mm can be measured with an accuracy of 1% and a resolution of 1 mm. It ta kes about 40 s to determine the moisture content at a specific positio n. Copyright (C) 1996 Elsevier Science Inc.