The Transition Zone between the Cement Paste and the Normalweight and the Lightweight Aggregates

In this study, the influence of aggregates on the aggregate-cement interfacial zone of concrete mixtures were discussed. Lightweight concrete can be produced with a combination of fine and coarse lightweight aggregate or coarse lightweight aggregate and normalweight fine aggregate. In this study, coarse lightweight aggregates were fully replaced with normalweight aggregate in concretes. In order to investigate the aggregate-cement matrix interfacial transition zone (ITZ), SEM observations were performed. The interface zone was in tight and locking bond between the two phases of all concretes. Cold bonded lightweight aggregates strengthened and narrowed the transition zone because of consuming the calcium hydroxide.

Keywords:

Interfacial zone , Aggregate , SEM.