Characteristics of lightweight aggregate concrete interfacial transition zone

The paper presents the characteristics of the interfacial zone between the lightweight aggregate produced on the basis of waste materials and binder matrix with the application of the methods SEM, EDS and the Vickers micro hardness test. On the basis of the SEM and EDS analysis, as well as the criteria for the atomic ratio of elements which compose some products of hydration, we can gain insight into the dominant composition of the interfacial zone. The values of the Vickers micro hardness test for four kinds of tested concrete after seven days of hydration is impossible to correlate with the composition of the interfacial zone in reliable way, whereas after twenty eight days the differences in values are insignificant.