IMPROVING THE STRUCTURE OF THE INTERFACIAL ZONE AND ITS INFLUENCE ON THE LONG-TERM BEHAVIOR OF MORTARS

The structure of the interfacial zone between cement paste and aggrega te was improved by using a pretreated quartz aggregate on whose surfac e the hydraulic mineral beta-C2S was directly formed. The composition and morphology of the structure of the interfacial zone was examined, and its influence was studied by comparisons between mortars made with pretreated quartz aggregate and with normal quartz aggregate. The res ults showed that the composition and morphology of the interfacial zon e were substantially improved by the hydration of the mineral beta-C2S of the pretreated quartz aggregate. The influence of;he interfacial s tructure on the strength of mortars was related to structural developm ent, it appears to be slight at early hydration, but significant at la te hydration.