MRI: A complementary tool for imaging cement pastes

This study examined the advantages and limitations of imaging cement paste with magnetic resonance imaging (MRI) using the single point imaging (SPI) sequence. Cement paste samples made with low water to cement (w/c) ratios were examined. The resolutions that could be attained in the images depended on the sizes of the samples. This technique, however, proved to be sensitive to water concentration gradients and allowed monitoring of water diffusion into the paste samples. In order to calibrate the features of the MR image, a comparison was made between electron micrographs and MR images of the same specimens. This revealed that the former could produce higher resolution images, however, considerable time was needed for sample preparation, the sample integrity was not guaranteed and only a small area of the sample could be viewed. In contrast, MRI offered in situ images which were three-dimensional and took less time to obtain than the electron micrographs but were of lower resolution. It is concluded that MRI could be a valuable tool for imaging cement pastes provided the features of the images have been “calibrated” by comparison with other, better known, techniques.