QUANTITATIVE BACKSCATTERED ELECTRON ANALYSIS OF CEMENT PASTE

Procedures are developed to obtain reproducible quantitative data from polished specimens of cement paste using automated backscattered electron imaging. Signal production, contrast, image resolution, and imaging techniques are discussed. Preparation of a silicon-magnesium standard is described. Typical results and a statistical basis for establishing the number of frames required to provide confidence in the results are presented. The silicon-magnesium standard provides an objective method for setting both a scanning electron microscope and an image analysis system for quantitative backscattered electron analysis of phases within cement paste. The number of frames required for a selected degree of confidence decreases, but the total area required increases as magnification decreases. The number of frames is also a function of the specific phase, being greatest for unhydrated cement particles and least for inner product and calcium silicate hydrate.