Abstract
A realistic understanding of the microstructure of freshly-mixed mortars (and concretes) is needed to provide a framework for visualizing and quantitatively modeling the patterns of cement hydration and space filling that are developed during hydration. In this paper the author discusses (a) postulated cement particle arrangements that have been used as starting assemblages in computer models of cement hydration, and their shortcomings; and (b) prospective experimental methods to assess the actual starting arrangements of particles in real freshly-mixed mortars and concretes. Scanning electron microscope investigations of fast-frozen fresh mortars suggest that the starting states assumed in current mathematical modeling for cement pastes are far from realistic. Several possible methods are discussed that may be capable of obtaining three-dimensional information on the actual starting states in fresh mortars or concretes.
