Abstract
This Guide is an introduction to the basic concepts of using 1H nuclear magnetic resonance (NMR) relaxometry to determine the state of water in cement, and hence the degree of cure of the cement and the cement microstructure, in particular the porosity. The Guide provides information on calibrating the equipment, the NMR responses that can typically be found from cement and on how to quantify the information obtained. Recommendations are made for the specification of suitable equipment, the set-up procedures required, and the experiments to be performed. Detailed results of an international round robin are included to demonstrate the usability, repeatability and accuracy of the method. The preparation of suitable non-cementitious reference materials is discussed.