Nuclear magnetic resonance study of diffusion and relaxation in hydrating white cement pastes of different water content

While the nuclear spin relaxation time changes in hydrating cement material s have been widely studied by various groups during the last 20 years, data on the self-diffusion behavior of the pore water during hydration of a cem ent paste are much scarcer. Taking advantage of improved spectrometer hardw are for pulsed field gradient diffusometry and a specialized pulse sequence which is designed to compensate the detrimental effects of inner magnetic field gradients in the sample we have studied the water self-diffusion beha vior in pastes prepared from white cement at various water/cement ratios. F or the same mixtures, studies of the transverse spin relaxation behavior we re also conducted. A comparison of the results from both techniques shows t hat the diffusion coefficient starts to decrease only much later than the r elaxation times for all pastes studied. (C) 2001 American Institute of Phys ics.