Microstructure and texture of hydrated cement-based materials: A proton field cycling relaxometry approach

We show how the measurement of proton nuclear magnetic spin-lattice relaxation as a function of magnetic field strength (and hence nuclear Larmor frequency) can provide reliable information on the microstructure (specific surface area and pore size distribution) throughout the progressive hydration of cement-based materials. We present in details the experimental and theoretical characteristic features of the relaxation dispersion to support an interpretation in terms of coupled solid-liquid relaxation at pore interfaces, surface diffusion, and nuclear paramagnetic relaxation. The measurement does not require any drying temperature modification and is sufficiently fast to be applied continuously during the progressive hydration of the material. Coupling this method with the standard proton nuclear spin relaxation and high resolution NMR allows us to follow the development of micro-scale texture within the material.