NMR for Non-Destructive Testing of Materials

Nuclear Magnetic Resonance (NMR) offers a variety of advantages for nondestructive testing (NDT) applications. With appropriate instrumentation engineering, it can be completely nondestructive and noncontacting. In the past, restrictions on sample size, operational restraints, and apparatus size, weight and cost have limited the practical utility of NMR methods. Recently, the development of a portable, one-sided access equipment (Southwest Research Institute, San Antonio, TX) has greatly expanded the potential for NMR application outside the laboratory. This new tool allows spatially resolved measurements on large objects, which are not accessible to conventional NMR. On porous building materials NMR can be used to characterise the porous structure. With the aid of the one-sided access technique moisture distribution proviles were mapped during wetting and drying to characterise the dynamics of water transport within porous materials. On crosslinking polymers but also on hydrating ceme nts, this new technique can be used to determine curing state.