INTERFACIAL TRANSITION ZONE MODIFICATION OF SULPHOALUMINATE CEMENT MORTAR

The effects of the interfacial transition zone (ITZ) of sulphoaluminate cement mortar on the properties of the mortar were studied. In order to improve the strength and impermeability of concrete, the surfaces of aggregates were coated with fine cement particles before the concrete was mixed, which decreased the thickness and the connectivity of the ITZ. The quantity of fine cement particles were calculated approximately with mathematical models. The structure of ITZ was studied by scanning electron microscope, mercury intrusion porosimetry. The results indicate that the pre-coated aggregates decrease the porosity and improve the compression strength and impermeability of sulphoaluminate cement mortar. In addition, ettringite is the main hydration product in the ITZ.