Direct measurement of water self-diffusion in hardening blast furnace slagcement pastes by means of nuclear magnetic resonance techniques

Recently, we have reported the unusual nuclear spin relaxation behavior of water in hardening blast furnace slag mixtures and suggested an explanation for the observed changes in the spin relaxation times based on diffusion e ffects in inner magnetic field gradients in the paste. Meanwhile, we have s ucceeded in measuring the self-diffusion coefficient of water in the harden ing pastes directly by means of a special pulsed field gradient technique i n which the effects of internal magnetic field gradients in a sample can be compensated for. Compared to water self-diffusion in ordinary cement mater ials, we find a much stronger decrease of the self-diffusion coefficient in the slag based cements. (C) 2001 American Institute of Physics.