ESTIMATION OF THE POROSITY OF PORTLAND CEMENT PASTES USING BACKSCATTERED ELECTRON IMAGE

Microscopy plays an important role in the examination of cementitious materials. Electron-optical techniques allowexamination of microstructural details. The increased application of scanning electron microscopy in cement and concreteinvestigations has brought attention to the estimation of the porosity. Backscattered Electron image has been established as amethod for quantitative analysis of hardened cement paste. This paper describes work and its application to Ordinary Portlandcement paste. Results show that the technique can be used to determine the porosity of Portland cement pastes. The success ofthese investigations is, influenced by the type and quality of specimen preparation. In particular, backscattered electron and Xrayimaging modes are influenced by the specimen surface characteristics, with the ideal surface being highly polished. Thetechnique can be a powerful tool to determine this essential factor of durability in concrete materials.Keys words: porosities, cement paste, strength, Scanning electron microscope, methanol exchange